Startseite Naturwissenschaften Synthesis and optimization of long-chain fatty acids via the oxidation of long-chain fatty alcohols
Artikel Open Access

Synthesis and optimization of long-chain fatty acids via the oxidation of long-chain fatty alcohols

  • Pengfei Shi , Wensen Liu , Hui Su , Yan Li und Zhaowu Zhu EMAIL logo
Veröffentlicht/Copyright: 16. September 2024
Artikel downloaden (PDF)
Veröffentlichen auch Sie bei De Gruyter Brill
Manuskript einreichen Informationen für Autor*innen
Green Processing and Synthesis
Aus der Zeitschrift Green Processing and Synthesis Band 13 Heft 1

Abstract

The oxidation of long-chain fatty alcohols with Jones reagent to prepare long-chain fatty acids is an efficient and economical method. The by-product of chromium sulfate is electrolyzed and oxidized to hexavalent chromium, which is recycled to avoid the emission of toxic by-products. In this article, the process conditions for the preparation of carboxylic acid by chromium reagent oxidizing alcohol are optimized, and the effects of various reaction conditions on the experiment are explored. Innovatively, the reaction was optimized by reverse addition. The two synthesis methods are compared by orthogonal experiments, and the optimal reaction conditions for oxidation are determined: the organic solvent of alcohol is added to the acidified Jones reagent by reverse addition; the amount of chromium reagent is 1.5 times the required stoichiometry; the chromium concentration in chromium reagent is 2.5 mol·L−1; the reaction temperature was lower than 30°C and the reaction time was 4 h. Under the optimized reaction conditions, the formation of by-products was effectively inhibited, and the conversion rate of alcohol oxidation to carboxylic acid was increased from 80% to more than 90%.

Graphical abstract

Keywords: Jones reagent; long-chain fatty alcohol; long-chain fatty acid; orthogonal experiment

1 Introduction

Long-chain fatty acids are important and abundant organic compounds [1] that are widely used in food, medicine [2], plastics, surfactants [3], extractants [4], lubricants [5], and other industries. Therefore, the production and preparation of long-chain fatty acids has always been the research hotspot of the chemical industry.

The synthesis methods of carboxylic acids mainly include the catalytic oxidation of alcohols or aldehydes [6,7,8,9], the hydrolysis of nitriles or lipids [10], etc. The hydrolysis of nitrile is generally carried out in the water solvent of concentrated sulfuric acid, but in some cases, the hydrolysis of nitrile will stay in the amide step, which is difficult to further hydrolyze, and the production process is complex [11]. The hydrolysis of esters requires reflux in an aqueous solution of KOH or NaOH, and this reaction also produces by-products that are difficult to separate, which makes it difficult to satisfy the needs of industrial production [12]. One-step catalytic oxidation of primary alcohols to carboxylic acids can be completed at room temperature using oxygen in the air as an oxidant using noble metal catalysts. This method has a wide range of applicability and selectivity, and the yield of carboxylic acids is more than 80%. However, the price of the catalyst is extremely expensive and difficult to recover, and some catalysts will also lead to the deactivation of the oxidant in the reaction [13]. Therefore, the preparation of carboxylic acids remains a great challenge, and more efficient and economical methods are needed to synthesize organic carboxylic acids.

Among the methods for preparing carboxylic acids, preparing carboxylic acids by oxidation of alcohols is one of the most basic chemical methods [14]. Long-chain fatty alcohols are difficult to oxidize owing to their stable properties and, like most organic matter, are insoluble in water. Therefore, it needs to be achieved by stoichiometric and efficient oxidants. The preparation of carboxylic acid by alcohol oxidation is generally achieved by stoichiometric high-efficiency oxidants, and common inorganic oxidants include potassium permanganate [15], chromate [16], ruthenium tetroxide [17], and others [18]. One of the reagents mentioned above is chromium(vi)-based reagents that are widely utilized in the oxidation of alcohols to carbonyl compounds, and Jones reagent is the most commonly used reagent in these chromium(vi)-based reagents. During the Jones oxidation of primary alcohols, aldehydes react with water and alcohols under acidic aqueous media to produce hydrates and hemiacetals [19], which are then oxidized to carboxylic acids and by-product dipolyesters, respectively, resulting in a low conversion rate [20]. Therefore, this study innovatively uses the “reverse addition” Jones oxidation method to prepare long-chain fatty acids with long-chain fatty alcohols as raw materials. The orthogonal experiment was designed to compare the two experimental methods of reverse addition and forward addition, and it was confirmed that this method can effectively inhibit the production of polyester by-products. The reaction time, the amount of Jones reagent, the concentration of chromium in Jones reagent, the concentration of sulfuric acid in Jones reagent, and other conditions were optimized, and finally, the optimal process conditions for the preparation of long-chain fatty acids by this method were obtained. For the chromium by-products produced by Jones oxidation, trivalent chromium was oxidized to hexavalent chromium by electrolysis and reused to avoid the harm of toxic by-products to the environment.

2 Principles and methods

2.1 Experimental principles

The reaction of the chromium reagent oxidizing alcohols is performed in an aqueous solution, starting with the reaction of chromium trioxide with water under acidic conditions, resulting in a balanced mixture containing chromic acid and its oligomers [21], as shown in Scheme 1. Chromic acid first reacts with the primary alcohol to form chromate, which gradually evolves into an intermediate aldehyde. This aldehyde is in equilibrium with its hydrate, after which further the reaction of the aldehyde water mixture with chromic acid results in the formation of a new chromate [22,23], which is decomposed into a carboxylic acid as in Scheme 2.

Scheme 1 Synthesis of Jones’ reagent.
Scheme 1

Synthesis of Jones’ reagent.

Scheme 2 Mechanism of oxidation of primary alcohols to carboxylic acids.
Scheme 2

Mechanism of oxidation of primary alcohols to carboxylic acids.

The by-product reaction is expressed in Scheme 3. In the process of dropping Jones reagent to primary alcohol, a large amount of alcohol is first contacted with a small amount of Jones reagent to form a large amount of intermediate aldehyde. The alcohol in the system reacts with an aldehyde to form a hemiacetal by-product, and then a dipolyester by-product is formed under the reaction of chromic acid [24].

Scheme 3 Mechanism of by-product reaction.
Scheme 3

Mechanism of by-product reaction.

2.2 Experimental method

The normal addition of the Jones oxidation method: An appropriate amount of chromium trioxide was placed in a 500 ml beaker, and an appropriate amount of deionized water was added and stirred to dissolve. A certain concentration of sulfuric acid solution was prepared and slowly added to the chromium oxide solution, stirred to cool to room temperature to obtain the chromium reagent. Then, a certain amount of long-chain fatty alcohol was taken in a 1 L three-necked flask, and three times the quality of dichloromethane was added to it as a solvent. The prepared chromium reagent was slowly added dropwise to the dichloromethane solution of long-chain fatty alcohol below 20°C. After the chromium reagent was added dropwise, it was allowed to stand for a certain time to stop the reaction. The liquid organic matter, which was the crude product, was separated.

The reverse addition of the Jones oxidation method: The configuration method of the Jones reagent and dichloromethane solution of long-chain fatty alcohol is the same as that of the previous process. The difference is that the chromium reagent solution was slowly added to the dichloromethane solution of the long-chain fatty alcohol rather than slowly adding the chromium reagent to the dichloromethane solution of the long-chain fatty alcohol. Similarly, after the reaction was complete, the crude product was separated.

2.3 Characterization and measurements

2.3.1 Determination of the conversion rate

The reaction conversion rate is calculated by the acid value of the product. The acid value is a measurement standard for the number of free carboxylic acid groups in the product. The higher the acid value, the more alcohol hydroxyl groups are converted into carboxyl groups, and the higher the conversion rate. The determination of acid value was carried out in a 250 ml conical flask. The sample with a mass of m (g) was added and dissolved in 20 ml deionized water and 10 ml ethanol. After shaking well, four to five drops of phenolphthalein were added dropwise. The titration was carried out with KOH standard solution at a concentration of c 1 (mol·L−1). When the sample solution was slightly red, and there was no significant fading within 15 s, the titration endpoint was determined. The volume of the standard titration solution consumed is recorded as V (ml). Blank experiments were performed according to the above steps, and the volume of the standard titration solution consumed was recorded as V 1 (ml). The iodine value was calculated using Eq. 1, where X av is the acid value (mg·g−1).

(1) X av = ( V − V 1 ) × c 1 × 56.1 m

In this study, the product is a mono-saturated carboxylic acid, so the conversion rate of the reaction can be calculated according to Eq. 2 according to the acid value. Among them, X av is the acid value of the product, M r is the relative molecular mass of the carboxylic acid product, and Conv. is the reaction conversion rate (%).

(2) Conv . = X av × M r 56.1 × 1 , 000 × 100

2.3.2 Determination of the iodine value

The iodine value is an indicator of the degree of unsaturation in fatty acid organic compounds. The iodine value was determined in a 250 ml conical flask. The sample with a mass of m (g) was weighed using an analytical balance, and the sample was dissolved with 40–60 ml alcohol. The pipette was accurately moved into 10 ml Wechsler’s reagent (iodine chloride–acetic acid mixed solution). After shaking, the conical flask was sealed in the dark for 0.5 h, and then the excess concentration of 15% potassium iodide solution was added. The sodium thiosulfate standard solution with a calibrated concentration of c 2 (mol·L−1) was titrated. When the yellow color of iodine was close to disappearing, the excess starch solution was added to continue the titration until the blue just disappeared at the titration endpoint. The volume of the standard titration solution consumed is recorded as V 2 (ml). Blank experiments were performed according to the above steps, and the volume of the standard titration solution consumed was recorded as V 3 (ml). The iodine value X iv (g/100 g) was calculated using Eq. 3,

(3) X iv = ( V 2 − V 1 ) × c 2 × 12.69 m

3 Results and discussion

3.1 Jones oxidation under normal addition

3.1.1 Effect of chromium reagent dosage

Jones reagent is an important oxidant in the reaction of alcohol oxidation to prepare carboxylic acid. The amount of Jones reagent in the reaction directly affects the conversion rate of carboxylic acid. The effect of the amount of Jones reagent on the conversion rate of carboxylic acid was investigated under the following conditions: temperature was <30°C, the holding time was 4 h, and the chromium concentration in the chromium reagent was 2.5 mol·L−1. The results are presented in Figure 1.

Figure 1 Effect of chromium reagent dosage.
Figure 1

Effect of chromium reagent dosage.

The conversion rate of carboxylic acid increased with the increase of the amount of Jones reagent. When the amount of Jones reagent reached three times, it was stable at about 90%. When the amount of Jones reagent reached four times of stoichiometry, the acid value of long-chain fatty acids was the highest, which was 91.7%, while the iodine value was always at 3 g/100 g, indicating that the content of unsaturated by-products in the product was low. When the amount of Jones reagent increased five times, the conversion rate of carboxylic acid decreased to a certain extent. This may be because when the amount of Jones reagent reaches a certain amount, the strong oxidation of Jones reagent will lead to the cleavage of the carbon–carbon bond of the intermediate chromate, which in turn produces some by-products. The broken carbocation group R+ has strong stability, which further strengthens the side reaction. Therefore, the optimized Jones reagent dosage is selected at 3.5 times of stoichiometry.

3.1.2 Effect of the reaction time

The effect of the reaction time on the conversion rate of carboxylic acid was investigated by controlling the stoichiometric amount of Jones reagent to 3.5 times, the reaction temperature to be lower than 30°C, and the concentration of chromium in Jones reagent to be 2.5 mol·L−1.

As presented in Figure 2, at 0.5 h, the acid value of carboxylic acid is low, while the iodine value is high. This is because, in the initial stage of the reaction, chromic acid reacts with primary alcohol to form intermediate products such as chromic acid ester and aldehyde, and the intermediate product is converted into carboxylic acid as the reaction proceeds. After 1 h of reaction, the acid value of carboxylic acid almost no longer increases, indicating that the Jones oxidation reaction is relatively rapid, and the conversion rate of carboxylic acid is stable at more than 85%. This is because as the reaction proceeds, a large number of carboxylic acids and some intermediate aldehydes and esters are produced in the system. The presence of these by-products inhibits the conversion of alcohols to carboxylic acids, and the reaction system tends to be stable. However, the conversion rate of carboxylic acid decreased after 6 h of reaction time, which may be due to the esterification reaction between the raw material primary alcohol and the product carboxylic acid in the presence of sulfuric acid. The appearance of the ester was confirmed by the mass spectrum of the product carboxylic acid. Under the limitation of sulfuric acid concentration and temperature, the esterification reaction was not complete, so the conversion rate of carboxylic acid did not decrease significantly. Considering comprehensively, the optimal reaction time was determined to be 4.5 h.

Figure 2 Effect of the reaction time.
Figure 2

Effect of the reaction time.

3.1.3 Effect of concentration of Jones reagent

Jones reagent is an aqueous solution composed of chromium trioxide, sulfuric acid, and water in a certain proportion, in which the stoichiometric ratio of chromium trioxide and concentrated sulfuric acid is 2:3. The maximum concentration of chromium in the chromium reagent is not more than 3 mol·L−1. By controlling the reaction temperature below 30°C, the amount of chromium reagent is three times the stoichiometry, and the reaction time is controlled at 4 h. The influence of the concentration of chromium in the chromium reagent on the oxidation reaction is explored, and the results are presented in Figure 3.

Figure 3 Effect of the concentration of the chromium reagent.
Figure 3

Effect of the concentration of the chromium reagent.

When the concentration of chromium in the Jones reagent is lower than 1.5 mol·L−1, the conversion rate of the product carboxylic acid is significantly lower than that when the concentration of chromium in the Jones reagent is higher than 1.5 mol·L−1. This is because the presence of a large amount of water reduces the oxidation of the Jones reagent and limits the oxidation reaction. When the concentration of chromium in the Jones reagent is higher than 1.5 mol·L−1, the oxidation of the Jones reagent is sufficient to meet the requirements of the reaction. This experiment shows that the oxidation of the Jones reagent increases with an increase in chromium concentration. However, the volume proportion of the Jones reagent with higher concentration in the reactor is smaller, and the reaction efficiency is higher when other reaction conditions are consistent. Therefore, the higher chromium concentration in the Jones reagent is beneficial to the oxidation reaction.

3.2 Jones oxidation under reverse addition

In this study, the method of reverse addition is used to carry out the experiment, and the two addition programs are compared. The results are shown in Figure 4.

Figure 4 Comparison of two oxidation methods.
Figure 4

Comparison of two oxidation methods.

Through the comparison of histograms, it was found that under the same oxidation conditions, the reverse addition method effectively improved the conversion rate of the reaction. This is because, in the process of slowly adding alcohol to the Jones reagent, the alcohol first comes in contact with a large amount of excess chromic acid and is quickly converted into carboxylic acid [25]. In this way, the accumulation of high-concentration intermediate aldehydes is effectively prevented, and the contact reaction with the starting alcohol is avoided to form a large number of hemiacetals, which reduces the concentration of hemiacetals formed in the reaction and increases the conversion rate of carboxylic acids [26]. With an increase of the amount of Jones reagent, the conversion rate of primary alcohol to carboxylic acid did not increase significantly, which indicated that the amount of Jones reagent had little effect on the conversion rate of the reaction. Therefore, the effect of feeding time and sulfuric acid concentration on the reaction was investigated under the condition that the amount of Jones reagent was 1.5 times stoichiometric.

3.2.1 Effect of the feeding speed

Feeding speed is an important factor affecting the conversion of the intermediate aldehyde to carboxylic acid. Controlling the feeding speed can avoid contact between the intermediate aldehyde and alcohol. Therefore, we investigated the effect of the feeding rate of alcohol on the reaction results by adding quantitative alcohol to the Jones reagent by fixing the amount of Jones reagent to be 1.5 times of the stoichiometry, the reaction time to be 4 h, and the chromium concentration in the Jones reagent to be 2.5 mol·L−1.

As presented in Figure 5, the feeding rate is reflected by changing the time when the quantitative alcohol is completely added to the Jones reagent. The change in the feeding rate has no significant effect on the conversion rate and iodine value of the product carboxylic acid, which indicates that the intermediate aldehyde is not easy to accumulate in the system. The mixture of aldehyde and water is converted into carboxylic acid at an extremely fast rate in the system. The faster the feeding rate, the higher the temperature of the reaction system, which also has a certain effect on the conversion of aldehydes into carboxylic acids. However, a very fast feeding speed will make it difficult to control the temperature of the system. When the reaction temperature reaches above 40°C, the solvent loss is large. Therefore, 3 h is the optimized reaction condition.

Figure 5 Effect of the feeding speed.
Figure 5

Effect of the feeding speed.

3.2.2 Effect of sulfuric acid concentration

The higher concentration of sulfuric acid will improve the oxidation ability of the Jones reagent, which in turn makes the high concentration of intermediate aldehydes convert into carboxylic acids faster. In order to investigate the effect of sulfuric acid concentration in the Jones reagent on the experiment, the reverse feeding method was used. The amount of Jones reagent was 1.5 times the stoichiometric amount, the reaction holding time was 4 h, and the chromium concentration in the Jones reagent was 2 mol·L−1. The experiment was carried out with the concentration of sulfuric acid in the Jones reagent as a variable. The experimental results are shown in Figure 6.

Figure 6 Effect of sulfuric acid concentration.
Figure 6

Effect of sulfuric acid concentration.

The results show that the concentration of sulfuric acid in the Jones reagent is smaller than that below 3.92 mol·L−1 when the concentration of sulfuric acid is above 3.92 mol·L−1. This is because with the increase of sulfuric acid concentration, the oxidation ability of the Jones reagent increases, which increases the conversion rate of carboxylic acid. When the concentration of sulfuric acid in the Jones reagent reaches 5.31 mol·L−1, the conversion rate of carboxylic acid begins to decrease. This is because when the concentration of sulfuric acid is too high, the oxidation of Jones’ reagent is too strong, which may cause the cracking of long-chain fatty alcohols, which in turn produces other by-products. This can be seen from the increase of iodine value. Although the higher concentration of sulfuric acid in the Jones oxidation reaction system has higher oxidizability, this may cause the reaction of acid-sensitive functional groups or protective groups in the reactants. In this case, when the reaction substrate is in contact with a large amount of excessive oxidants, the sensitive functional groups will be destroyed, and the target product will not be obtained, resulting in a decrease in the conversion rate of carboxylic acids. Although the increase of sulfuric acid concentration can increase the oxidizability of Jones reagent, the concentration of chromium in the system is relatively reduced, and the volume of Jones reagent required is relatively increased, thus reducing the production efficiency. Therefore, it is not an ideal method to increase the conversion rate of carboxylic acid by increasing the concentration of sulfuric acid.

3.3 Comparison of orthogonal experiments

Under the condition that the amount of Jones reagent is 1.5 times stoichiometric, the concentration is 2.5 mol·L−1, and the reaction holding time is 4 h, the conversion rate of carboxylic acid obtained by the oxidation method under normal addition is about 80%. The conversion rate of carboxylic acid can reach more than 90% when the oxidation method under reverse addition is used, which indicates that the oxidation method under the reverse procedure can effectively inhibit the formation of by-products, thereby increasing the conversion rate of carboxylic acid.

In order to analyze the influence of the two methods on the oxidation results more comprehensively, reagent concentration, reagent dosage, and holding time were selected as variables to design orthogonal experiments. In this experiment, an L9 (33) orthogonal experiment table was selected. Among them, the Jones reagent concentration factor setting level was 2.5, 2, and 1.5 mol·L−1; the level of Jones reagent dosage factor setting was two, three, and four times stoichiometry; the levels of reaction time factors of normal addition were 3, 4.5, and 6 h; and the levels of reaction time factors of reverse addition were 2, 3.5, and 5 h. The orthogonal experimental design schemes of forward addition and reverse addition with three factors and three levels were obtained, respectively. The specific parameter settings are shown in Table 1.

Table 1

Orthogonal experimental design table

Method Level Experimental factors
Cr6+ (mol·L−1) Dosage (stoichiometric multiples) Time (h)
Normal addition 1 2.5 2 3
2 2 3 4.5
3 1.5 4 6
Reverse addition 1 2.5 2 2
2 2 3 3.5
3 1.5 4 5

According to the design of the orthogonal experiment table for experimental analysis, the acid value results of the product carboxylic acid in an orthogonal experiment are shown in Table 2 (normal addition) and Table 3 (reverse addition).

Table 2

Orthogonal experimental results (normal addition)

Number Cr6+ (mol·L−1) Dosage (stoichiometric multiples) Time (h) Acid value (mg·g−1)
1 2.5 2 3 181
2 2 3 3 181
3 1.5 4 3 159
4 2.5 3 4.5 188
5 2 4 4.5 185
6 1.5 2 4.5 179
7 2.5 4 6 196
8 2 2 6 178
9 1.5 3 6 187
Table 3

Orthogonal experimental results (reverse addition)

Number Cr6+ (mol·L−1) Dosage (stoichiometric multiples) Time (h) Acid value (mg·g−1)
1 2.5 2 2 167
2 2 3 2 183
3 1.5 4 2 169
4 2.5 3 3.5 195
5 2 4 3.5 193
6 1.5 2 3.5 159
7 2.5 4 5 199
8 2 2 5 171
9 1.5 3 5 174

The range analysis was carried out according to the acid value of the product carboxylic acid obtained by the orthogonal experiment. The analysis results are listed in Table 4 (normal addition) and Table 5 (reverse addition). The order of the factors affecting the acid value in the forward addition method is chromium reagent concentration > chromium reagent dosage > reaction time, and the order of the factors affecting the acid value in the reverse addition method is chromium reagent dosage > chromium reagent concentration > reaction time.

Table 4

Range analysis of the orthogonal experiment (normal addition)

Level Concentration Dosage Time
K1j 565 540 521
K2j 544 556 552
K3j 524 538 560
Rj 14 6 13
Table 5

Range analysis of the orthogonal experiment (reverse addition)

Level Concentration Dosage Time
K1j 560 497 519
K2j 547 551 547
K3j 502 561 543
Rj 19 21 9

From the data in the table, it can be found that the optimum acid value of the carboxylic acid obtained by the two experiments is above 200 mg·g−1, and the conversion rate of alcohol oxidation to carboxylic acid is about 91%. It is difficult to further improve the conversion rate of carboxylic acid. It may be because, in most cases, Jones oxidation is carried out by mixing the chromic acid solution with the acetone solution of the alcohol at room temperature, and a solvent other than acetone is rarely used. Because acetone is a polar organic solvent, when acetone is used as an organic solvent, the reaction intermediate, aldehyde–water mixture, can be better produced in the system and then converted into carboxylic acid. As an organic solvent with less polarity than acetone, dichloromethane can inhibit the formation of a high concentration of aldehyde–water mixture to a certain extent, so the conversion rate of alcohol oxidation to prepare carboxylic acid has a limit. This factor, together with various by-products and other factors, makes it difficult for the conversion rate of alcohol to carboxylic acid in this system to reach more than 95%. However, since dichloromethane is easier to separate and recycle, it can simplify the process and save costs in industrial production. Therefore, dichloromethane was selected as the organic solvent.

The optimized Jones oxidation conditions are as follows: the oxidation method of the reverse process is adopted, the solvent is dichloromethane, the dosage of Jones reagent is 1.5 times of stoichiometry, the concentration of Jones reagent is 2.5 mol·L−1, the feeding time is 3 h, and the reaction time is 4 h. Under these reaction conditions, the conversion rate of long-chain fatty alcohol to long-chain fatty acid was more than 90%.

3.4 Treatment of chromium sulfate by-product

In order to deal with chromium by-products and avoid serious pollution to the environment, the electrolytic method is used to oxidize the chromium sulfate solution to hexavalent chromium for recycling. In this study, the process conditions of electrolysis were explored by using chromium sulfate solution produced after the oxidation reaction as raw material.

The effect of electrolysis time on the concentration of Cr6+ was investigated by using 30% sulfuric acid at 20°C and 40°C. As shown in Figure 7, at 20°C, the conversion rate is stable at 24.64% after 6 h of electrolysis time, and the concentration of hexavalent chromium generated by electrolytic oxidation is about 0.62 mol·L−1. At 40°C, the conversion rate can reach 24.3% after 6 h of electrolysis time and keeps increasing. However, with an increase of hexavalent chromium concentration, the damage of its strong oxidation to the equipment also increases. Therefore, the reaction ends after 8 h, and the hexavalent chromium concentration is about 0.86 mol·L−1. By comparing the results at different temperatures, it can be found that increasing the temperature can effectively increase the electrolysis efficiency. It should be noted that the residual organic matter in the solution during the electrolysis of chromium sulfate solution may form a polymer on the electrode surface, which hinders the occurrence of the oxidation reaction on the electrode surface, thus affecting the current efficiency of Cr3+ electrolytic oxidation. The organic matter in the chromium sulfate solution can be extracted before the electrolysis operation to avoid the influence of the organic matter content on the electrolytic oxidation efficiency.

Figure 7 The effect of time on the electrolysis results at 20°C (a) and 40°C (b).
Figure 7

The effect of time on the electrolysis results at 20°C (a) and 40°C (b).

On the other hand, the concentration of sulfuric acid has a great influence on the electrolysis efficiency. As shown in Table 6, when the concentration of sulfuric acid increases from 20% to 40%, the concentration of hexavalent chromium increases first and then decreases. When the concentration of sulfuric acid is 30%, the concentration of hexavalent chromium produced by electrolysis is up to 0.855 mol·L−1. This is because the addition of sulfuric acid is beneficial to reduce the resistance, improve the conductivity of the solution, increase the current density, and shorten the reaction time. However, on the other hand, sulfuric acid is one of the products of the electrolysis reaction, and the excessive concentration of sulfuric acid is unfavorable to the oxidation reaction. In this experiment, when the amount of sulfuric acid added exceeds 30%, the hindering effect of sulfuric acid is greater than its promoting effect, so the concentration of sulfuric acid needs to be maintained within a certain range.

Table 6

Effect of sulfuric acid concentration on electrolysis

Sulfuric acid concentration (%) Time (h) Cr6+ (mol·L−1) Concentration (%)
20 6 0.807 30.8
30 6 0.855 32.7
40 6 0.821 31.4

The long-chain carboxylic acid was prepared from long-chain primary alcohol using the Jones oxidation method. The whole oxidation process and by-product electrolysis process were designed, as shown in Figure 8. The oxidation process was carried out in an oxidation reactor. The reaction products were carboxylic acid (oil phase) and chromium sulfate (aqueous phase). After separation, the crude product of the oil phase was separated and purified to obtain carboxylic acid, and the by-product chromium sulfate was used as the electrolyte. After preliminary treatment, Cr3+ was oxidized to Cr6+ by electrolysis, and then the primary alcohol was oxidized as an oxidant.

Figure 8 Schematic representation of the experiment.
Figure 8

Schematic representation of the experiment.

4 Conclusions

In summary, long-chain fatty carboxylic acids were prepared using two different methods of Jones oxidation, using long-chain fatty alcohols as raw materials. The preparation process of carboxylic acids was optimized by single-factor experiments, and orthogonal experiments were designed to compare the two methods. The results showed that the optimal production conditions for the preparation of long-chain fatty acids by the oxidation of long-chain fatty alcohols by Jones reagent were as follows: the organic solvent of alcohol was added dropwise to the Jones reagent for production, the amount of the Jones reagent required was 1.5 times of stoichiometry, the concentration of the Jones reagent was 2.5 mol·L−1, the feeding time was 3 h, and the reaction time was 4 h. Under the optimal conditions, the conversion rate of primary alcohol to carboxylic acid was more than 90%. Chromium sulfate is electrolyzed and oxidized to form hexavalent chromium for recycling, which meets the requirements of a green, clean, and environmentally friendly synthesis process.

Acknowledgment

This work was supported by the Major Research Plan of the National Natural Science Foundation of China (No. 92262305). The authors also thank Institutional Center for shared Technologies and Facilities of Institute of Process Engineering, Chinese Academy of Sciences.

  1. Author contributions: Pengfei Shi: writing – original draft, investigation, resources, data curation, validation, and formal analysis. Wensen Liu: methodology, validation, investigation, and data curation. Hui Su: conceptualization, validation, formal analysis, and project administration. Yan Li: investigation, resources, and data curation. Zhaowu Zhu: writing – review and editing, conceptualization, supervision, and funding acquisition.

  2. Conflict of interest: Authors state no conflict of interest.

  3. Data availability statement: The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

References

[1] Hong YK, Hong WH, Han DH. Application of reactive extraction to recovery of carboxylic acids. Biotechnol Bioprocess Eng. 2001;6:386–94.10.1007/BF02932319Suche in Google Scholar

[2] Asare-Addo K, Walton K, Ward A, Totea AM, Taheri S, Alshafiee M, et al. Direct imaging of the dissolution of salt forms of a carboxylic acid drug. Int J Pharmaceutics. 2018;551:290–9.10.1016/j.ijpharm.2018.09.048Suche in Google Scholar PubMed

[3] Herrera AG, Schmitt E, Panossian A, Vors JP, Leroux FR. New synthetic access to 3-fluoroalkyl-5-pyrazolecarboxylates and carboxylic acids. J Fluor Chem. 2018;214:17–23.10.1016/j.jfluchem.2018.07.010Suche in Google Scholar

[4] Sharaf M, Yoshida W, Kubota F, Goto M. Selective extraction of scandium by a long alkyl chain carboxylic acid/organophosphonic ester binary extractant. Solvent Extr Ion Exch. 2018;36:1–11.10.1080/07366299.2018.1532139Suche in Google Scholar

[5] Oshio T, Minfray C, Dassenoy F, Galipard J, Yagishita K. Dialkyl phosphonate with carboxylic acid as antiwear additives for ester-base lubricants. Wear. 2023;530:205042.10.1016/j.wear.2023.205042Suche in Google Scholar

[6] Ghafouri M, Moghadam M, Mehrani K, Daneshvar A. Supported ruthenium hydride catalysts for direct conversion of alcohols to carboxylic acids using styrene oxide as oxidant. Appl Organomet Chem. 2018;32:e4048.10.1002/aoc.4048Suche in Google Scholar

[7] Ruiz-Sanchez AJ, Vida Y, Suau R, Perez-Inestrosa E. Cation template assisted oligoethylene glycol desymmetrization by intramolecular Cannizzaro reaction of topologically remote aldehydes. Tetrahedron. 2008;64:11661–5.10.1016/j.tet.2008.10.015Suche in Google Scholar

[8] Ishikawa F, Yamaguchi H, Saegusa J, Inamura K, Mimura T, Nishi T, et al. Cyclic guanidines. XVI. Synthesis and biological activities of tetracyclic imidazo[2,1-b]quinazolinone derivatives. Chem Pharm Bull. 1985;33:3336–48.10.1248/cpb.33.3336Suche in Google Scholar PubMed

[9] Koshikari Y, Sakakura A, Ishihara K. N,N-Diarylammonium pyrosulfate as a highly effective reverse micelle-type catalyst for hydrolysis of esters. Org Lett. 2012;14:3194–7.10.1021/ol301290cSuche in Google Scholar PubMed

[10] Brown HC, Kulkarni SV, Khanna VV, Patil VD, Racherla US. Organoboranes for synthesis. 14. Convenient procedures for the direct oxidation of organoboranes from terminal alkenes to carboxylic acids. J Org Chem. 1992;57:6173–7.10.1021/jo00049a024Suche in Google Scholar

[11] Khurana JM, Sehgal A. An efficient and convenient procedure for ester hydrolysis. Org Prep Proced Int. 1995;26(5):580–3.10.1080/00304949409458062Suche in Google Scholar

[12] Singh A, Singh SK, Saini AK, Mobin SM, Mathur P. Facile oxidation of alcohols to carboxylic acids in basic water medium by employing ruthenium picolinate cluster as an efficient catalyst. Appl Organomet Chem. 2018;32:e4574.10.1002/aoc.4574Suche in Google Scholar

[13] Jiang X, Zhang J, Ma S. Iron catalysis for room-temperature aerobic oxidation of alcohols to carboxylic acids. J Am Chem Soc. 2016;138:8344–7.10.1021/jacs.6b03948Suche in Google Scholar PubMed

[14] Caron S, Dugger RW, Ruggeri SG, Ragan JA, Ripin DH. Large-scale oxidations in the pharmaceutical industry. ChemInform. 2006;106:2943–89.10.1021/cr040679fSuche in Google Scholar PubMed

[15] Nai-Ju H, Xu-liang-heng. A Novel method for preparation of hydroxyalkyl carboxylates by potassium permanganate oxidation of cyclic acetals. Synth Commun. 1990;20:1563–7.10.1080/00397919008052874Suche in Google Scholar

[16] Mahmood A, Robinson GE, Powell L. Improved oxidation of an alcohol using aqueous pemanganate and PTC. Org Process Res Dev. 1999;3:363–4.10.1021/op990021hSuche in Google Scholar

[17] Marshall AJ, Lin JM, Grey A, Reid IR, Cornish J, Denny WA. Long-chain triazolyl acids as inhibitors of osteoclastogenesis. Bioorg Med Chem. 2013;21:4112–9.10.1016/j.bmc.2013.05.013Suche in Google Scholar PubMed

[18] Bowden K, Heilbron IM, Jones ERH, Weedon BCL. 13. Researches on acetylenic compounds. Part I. The preparation of acetylenic ketones by oxidation of acetylenic carbinols and glycols. J Chem Soc. 1946;39–45.10.1039/jr9460000039Suche in Google Scholar

[19] Tojo G, Fernández M. Oxidation of primary alcohols to carboxylic acids. Springer; 2006.10.1007/0-387-35432-8Suche in Google Scholar

[20] Paquette LA. Encyclopedia of reagents for organic synthesis. Wiley; 2009.Suche in Google Scholar

[21] Bekish AV. Carbon–carbon bond fission on oxidation of primary alcohols to carboxylic acids. Tetrahedron Lett. 2012;53:3082–5.10.1016/j.tetlet.2012.04.035Suche in Google Scholar

[22] Mosset P, Grée R, Falck JR. Synthesis of two intermediate phosphonium salts for 5,20 and 15,20-DiHetes. Synth Commun. 1989;19:645–58.10.1080/00397918908050711Suche in Google Scholar

[23] Marples BA, Saint CG, Traynor JR. Regiochemistry of nucleophilic opening of β-substituted styrene oxides with thiolate anions: model experiments in the synthesis of leukotriene analogues. Chemischer Informationsdienst. 1986;17:567–74.10.1039/P19860000567Suche in Google Scholar

[24] Hunter AC, Priest SM. An efficient one-pot synthesis generating 4-ene-3,6-dione functionalised steroids from steroidal 5-en-3beta-ols using a modified Jones oxidation methodology. Steroids. 2006;71:30–3.10.1016/j.steroids.2005.07.007Suche in Google Scholar PubMed

[25] Dong J, Chen W, Wang S, Zhang J, Li H, Guo H, et al. Jones oxidation and high performance liquid chromatographic analysis of cholesterol in biological samples. J Chromatogr B. 2007;858:239–46.10.1016/j.jchromb.2007.08.038Suche in Google Scholar PubMed

[26] Holland, BC, Gilman, NW. An improved procedure for the oxidation of alkvnols to alkynoic acids. Synth Commun. 1974;4:203–10.10.1080/00397917408062073Suche in Google Scholar
Received: 2023-11-20
Accepted: 2024-04-28
Published Online: 2024-09-16

© 2024 the author(s), published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Artikel in diesem Heft

  1. Research Articles
  2. Green polymer electrolyte and activated charcoal-based supercapacitor for energy harvesting application: Electrochemical characteristics
  3. Research on the adsorption of Co2+ ions using halloysite clay and the ability to recover them by electrodeposition method
  4. Simultaneous estimation of ibuprofen, caffeine, and paracetamol in commercial products using a green reverse-phase HPTLC method
  5. Isolation, screening and optimization of alkaliphilic cellulolytic fungi for production of cellulase
  6. Functionalized gold nanoparticles coated with bacterial alginate and their antibacterial and anticancer activities
  7. Comparative analysis of bio-based amino acid surfactants obtained via Diels–Alder reaction of cyclic anhydrides
  8. Biosynthesis of silver nanoparticles on yellow phosphorus slag and its application in organic coatings
  9. Exploring antioxidant potential and phenolic compound extraction from Vitis vinifera L. using ultrasound-assisted extraction
  10. Manganese and copper-coated nickel oxide nanoparticles synthesized from Carica papaya leaf extract induce antimicrobial activity and breast cancer cell death by triggering mitochondrial caspases and p53
  11. Insight into heating method and Mozafari method as green processing techniques for the synthesis of micro- and nano-drug carriers
  12. Silicotungstic acid supported on Bi-based MOF-derived metal oxide for photodegradation of organic dyes
  13. Synthesis and characterization of capsaicin nanoparticles: An attempt to enhance its bioavailability and pharmacological actions
  14. Synthesis of Lawsonia inermis-encased silver–copper bimetallic nanoparticles with antioxidant, antibacterial, and cytotoxic activity
  15. Facile, polyherbal drug-mediated green synthesis of CuO nanoparticles and their potent biological applications
  16. Zinc oxide-manganese oxide/carboxymethyl cellulose-folic acid-sesamol hybrid nanomaterials: A molecularly targeted strategy for advanced triple-negative breast cancer therapy
  17. Exploring the antimicrobial potential of biogenically synthesized graphene oxide nanoparticles against targeted bacterial and fungal pathogens
  18. Biofabrication of silver nanoparticles using Uncaria tomentosa L.: Insight into characterization, antibacterial activities combined with antibiotics, and effect on Triticum aestivum germination
  19. Membrane distillation of synthetic urine for use in space structural habitat systems
  20. Investigation on mechanical properties of the green synthesis bamboo fiber/eggshell/coconut shell powder-based hybrid biocomposites under NaOH conditions
  21. Green synthesis of magnesium oxide nanoparticles using endophytic fungal strain to improve the growth, metabolic activities, yield traits, and phenolic compounds content of Nigella sativa L.
  22. Estimation of greenhouse gas emissions from rice and annual upland crops in Red River Delta of Vietnam using the denitrification–decomposition model
  23. Synthesis of humic acid with the obtaining of potassium humate based on coal waste from the Lenger deposit, Kazakhstan
  24. Ascorbic acid-mediated selenium nanoparticles as potential antihyperuricemic, antioxidant, anticoagulant, and thrombolytic agents
  25. Green synthesis of silver nanoparticles using Illicium verum extract: Optimization and characterization for biomedical applications
  26. Antibacterial and dynamical behaviour of silicon nanoparticles influenced sustainable waste flax fibre-reinforced epoxy composite for biomedical application
  27. Optimising coagulation/flocculation using response surface methodology and application of floc in biofertilisation
  28. Green synthesis and multifaceted characterization of iron oxide nanoparticles derived from Senna bicapsularis for enhanced in vitro and in vivo biological investigation
  29. Potent antibacterial nanocomposites from okra mucilage/chitosan/silver nanoparticles for multidrug-resistant Salmonella Typhimurium eradication
  30. Trachyspermum copticum aqueous seed extract-derived silver nanoparticles: Exploration of their structural characterization and comparative antibacterial performance against gram-positive and gram-negative bacteria
  31. Microwave-assisted ultrafine silver nanoparticle synthesis using Mitragyna speciosa for antimalarial applications
  32. Green synthesis and characterisation of spherical structure Ag/Fe2O3/TiO2 nanocomposite using acacia in the presence of neem and tulsi oils
  33. Green quantitative methods for linagliptin and empagliflozin in dosage forms
  34. Enhancement efficacy of omeprazole by conjugation with silver nanoparticles as a urease inhibitor
  35. Residual, sequential extraction, and ecological risk assessment of some metals in ash from municipal solid waste incineration, Vietnam
  36. Green synthesis of ZnO nanoparticles using the mangosteen (Garcinia mangostana L.) leaf extract: Comparative preliminary in vitro antibacterial study
  37. Simultaneous determination of lesinurad and febuxostat in commercial fixed-dose combinations using a greener normal-phase HPTLC method
  38. A greener RP-HPLC method for quaternary estimation of caffeine, paracetamol, levocetirizine, and phenylephrine acquiring AQbD with stability studies
  39. Optimization of biomass durian peel as a heterogeneous catalyst in biodiesel production using microwave irradiation
  40. Thermal treatment impact on the evolution of active phases in layered double hydroxide-based ZnCr photocatalysts: Photodegradation and antibacterial performance
  41. Preparation of silymarin-loaded zein polysaccharide core–shell nanostructures and evaluation of their biological potentials
  42. Preparation and characterization of composite-modified PA6 fiber for spectral heating and heat storage applications
  43. Preparation and electrocatalytic oxygen evolution of bimetallic phosphates (NiFe)2P/NF
  44. Rod-shaped Mo(vi) trichalcogenide–Mo(vi) oxide decorated on poly(1-H pyrrole) as a promising nanocomposite photoelectrode for green hydrogen generation from sewage water with high efficiency
  45. Green synthesis and studies on citrus medica leaf extract-mediated Au–ZnO nanocomposites: A sustainable approach for efficient photocatalytic degradation of rhodamine B dye in aqueous media
  46. Cellulosic materials for the removal of ciprofloxacin from aqueous environments
  47. The analytical assessment of metal contamination in industrial soils of Saudi Arabia using the inductively coupled plasma technology
  48. The effect of modified oily sludge on the slurry ability and combustion performance of coal water slurry
  49. Eggshell waste transformation to calcium chloride anhydride as food-grade additive and eggshell membranes as enzyme immobilization carrier
  50. Synthesis of EPAN and applications in the encapsulation of potassium humate
  51. Biosynthesis and characterization of silver nanoparticles from Cedrela toona leaf extracts: An exploration into their antibacterial, anticancer, and antioxidant potential
  52. Enhancing mechanical and rheological properties of HDPE films through annealing for eco-friendly agricultural applications
  53. Immobilisation of catalase purified from mushroom (Hydnum repandum) onto glutaraldehyde-activated chitosan and characterisation: Its application for the removal of hydrogen peroxide from artificial wastewater
  54. Sodium titanium oxide/zinc oxide (STO/ZnO) photocomposites for efficient dye degradation applications
  55. Effect of ex situ, eco-friendly ZnONPs incorporating green synthesised Moringa oleifera leaf extract in enhancing biochemical and molecular aspects of Vicia faba L. under salt stress
  56. Biosynthesis and characterization of selenium and silver nanoparticles using Trichoderma viride filtrate and their impact on Culex pipiens
  57. Photocatalytic degradation of organic dyes and biological potentials of biogenic zinc oxide nanoparticles synthesized using the polar extract of Cyperus scariosus R.Br. (Cyperaceae)
  58. Assessment of antiproliferative activity of green-synthesized nickel oxide nanoparticles against glioblastoma cells using Terminalia chebula
  59. Chlorine-free synthesis of phosphinic derivatives by change in the P-function
  60. Anticancer, antioxidant, and antimicrobial activities of nanoemulsions based on water-in-olive oil and loaded on biogenic silver nanoparticles
  61. Study and mechanism of formation of phosphorus production waste in Kazakhstan
  62. Synthesis and stabilization of anatase form of biomimetic TiO2 nanoparticles for enhancing anti-tumor potential
  63. Microwave-supported one-pot reaction for the synthesis of 5-alkyl/arylidene-2-(morpholin/thiomorpholin-4-yl)-1,3-thiazol-4(5H)-one derivatives over MgO solid base
  64. Screening the phytochemicals in Perilla leaves and phytosynthesis of bioactive silver nanoparticles for potential antioxidant and wound-healing application
  65. Graphene oxide/chitosan/manganese/folic acid-brucine functionalized nanocomposites show anticancer activity against liver cancer cells
  66. Nature of serpentinite interactions with low-concentration sulfuric acid solutions
  67. Multi-objective statistical optimisation utilising response surface methodology to predict engine performance using biofuels from waste plastic oil in CRDi engines
  68. Microwave-assisted extraction of acetosolv lignin from sugarcane bagasse and electrospinning of lignin/PEO nanofibres for carbon fibre production
  69. Biosynthesis, characterization, and investigation of cytotoxic activities of selenium nanoparticles utilizing Limosilactobacillus fermentum
  70. Highly photocatalytic materials based on the decoration of poly(O-chloroaniline) with molybdenum trichalcogenide oxide for green hydrogen generation from Red Sea water
  71. Highly efficient oil–water separation using superhydrophobic cellulose aerogels derived from corn straw
  72. Beta-cyclodextrin–Phyllanthus emblica emulsion for zinc oxide nanoparticles: Characteristics and photocatalysis
  73. Assessment of antimicrobial activity and methyl orange dye removal by Klebsiella pneumoniae-mediated silver nanoparticles
  74. Influential eradication of resistant Salmonella Typhimurium using bioactive nanocomposites from chitosan and radish seed-synthesized nanoselenium
  75. Antimicrobial activities and neuroprotective potential for Alzheimer’s disease of pure, Mn, Co, and Al-doped ZnO ultra-small nanoparticles
  76. Green synthesis of silver nanoparticles from Bauhinia variegata and their biological applications
  77. Synthesis and optimization of long-chain fatty acids via the oxidation of long-chain fatty alcohols
  78. Eminent Red Sea water hydrogen generation via a Pb(ii)-iodide/poly(1H-pyrrole) nanocomposite photocathode
  79. Green synthesis and effective genistein production by fungal β-glucosidase immobilized on Al2O3 nanocrystals synthesized in Cajanus cajan L. (Millsp.) leaf extracts
  80. Green stability-indicating RP-HPTLC technique for determining croconazole hydrochloride
  81. Green synthesis of La2O3–LaPO4 nanocomposites using Charybdis natator for DNA binding, cytotoxic, catalytic, and luminescence applications
  82. Eco-friendly drugs induce cellular changes in colistin-resistant bacteria
  83. Tangerine fruit peel extract mediated biogenic synthesized silver nanoparticles and their potential antimicrobial, antioxidant, and cytotoxic assessments
  84. Green synthesis on performance characteristics of a direct injection diesel engine using sandbox seed oil
  85. A highly sensitive β-AKBA-Ag-based fluorescent “turn off” chemosensor for rapid detection of abamectin in tomatoes
  86. Green synthesis and physical characterization of zinc oxide nanoparticles (ZnO NPs) derived from the methanol extract of Euphorbia dracunculoides Lam. (Euphorbiaceae) with enhanced biosafe applications
  87. Detection of morphine and data processing using surface plasmon resonance imaging sensor
  88. Effects of nanoparticles on the anaerobic digestion properties of sulfamethoxazole-containing chicken manure and analysis of bio-enzymes
  89. Bromic acid-thiourea synergistic leaching of sulfide gold ore
  90. Green chemistry approach to synthesize titanium dioxide nanoparticles using Fagonia Cretica extract, novel strategy for developing antimicrobial and antidiabetic therapies
  91. Green synthesis and effective utilization of biogenic Al2O3-nanocoupled fungal lipase in the resolution of active homochiral 2-octanol and its immobilization via aluminium oxide nanoparticles
  92. Eco-friendly RP-HPLC approach for simultaneously estimating the promising combination of pentoxifylline and simvastatin in therapeutic potential for breast cancer: Appraisal of greenness, whiteness, and Box–Behnken design
  93. Use of a humidity adsorbent derived from cockleshell waste in Thai fried fish crackers (Keropok)
  94. One-pot green synthesis, biological evaluation, and in silico study of pyrazole derivatives obtained from chalcones
  95. Bio-sorption of methylene blue and production of biofuel by brown alga Cystoseira sp. collected from Neom region, Kingdom of Saudi Arabia
  96. Synthesis of motexafin gadolinium: A promising radiosensitizer and imaging agent for cancer therapy
  97. The impact of varying sizes of silver nanoparticles on the induction of cellular damage in Klebsiella pneumoniae involving diverse mechanisms
  98. Microwave-assisted green synthesis, characterization, and in vitro antibacterial activity of NiO nanoparticles obtained from lemon peel extract
  99. Rhus microphylla-mediated biosynthesis of copper oxide nanoparticles for enhanced antibacterial and antibiofilm efficacy
  100. Harnessing trichalcogenide–molybdenum(vi) sulfide and molybdenum(vi) oxide within poly(1-amino-2-mercaptobenzene) frameworks as a photocathode for sustainable green hydrogen production from seawater without sacrificial agents
  101. Magnetically recyclable Fe3O4@SiO2 supported phosphonium ionic liquids for efficient and sustainable transformation of CO2 into oxazolidinones
  102. A comparative study of Fagonia arabica fabricated silver sulfide nanoparticles (Ag2S) and silver nanoparticles (AgNPs) with distinct antimicrobial, anticancer, and antioxidant properties
  103. Visible light photocatalytic degradation and biological activities of Aegle marmelos-mediated cerium oxide nanoparticles
  104. Physical intrinsic characteristics of spheroidal particles in coal gasification fine slag
  105. Exploring the effect of tea dust magnetic biochar on agricultural crops grown in polycyclic aromatic hydrocarbon contaminated soil
  106. Crosslinked chitosan-modified ultrafiltration membranes for efficient surface water treatment and enhanced anti-fouling performances
  107. Study on adsorption characteristics of biochars and their modified biochars for removal of organic dyes from aqueous solution
  108. Zein polymer nanocarrier for Ocimum basilicum var. purpurascens extract: Potential biomedical use
  109. Green synthesis, characterization, and in vitro and in vivo biological screening of iron oxide nanoparticles (Fe3O4) generated with hydroalcoholic extract of aerial parts of Euphorbia milii
  110. Novel microwave-based green approach for the synthesis of dual-loaded cyclodextrin nanosponges: Characterization, pharmacodynamics, and pharmacokinetics evaluation
  111. Bi2O3–BiOCl/poly-m-methyl aniline nanocomposite thin film for broad-spectrum light-sensing
  112. Green synthesis and characterization of CuO/ZnO nanocomposite using Musa acuminata leaf extract for cytotoxic studies on colorectal cancer cells (HCC2998)
  113. Review Articles
  114. Materials-based drug delivery approaches: Recent advances and future perspectives
  115. A review of thermal treatment for bamboo and its composites
  116. An overview of the role of nanoherbicides in tackling challenges of weed management in wheat: A novel approach
  117. An updated review on carbon nanomaterials: Types, synthesis, functionalization and applications, degradation and toxicity
  118. Special Issue: Emerging green nanomaterials for sustainable waste management and biomedical applications
  119. Green synthesis of silver nanoparticles using mature-pseudostem extracts of Alpinia nigra and their bioactivities
  120. Special Issue: New insights into nanopythotechnology: current trends and future prospects
  121. Green synthesis of FeO nanoparticles from coffee and its application for antibacterial, antifungal, and anti-oxidation activity
  122. Dye degradation activity of biogenically synthesized Cu/Fe/Ag trimetallic nanoparticles
  123. Special Issue: Composites and green composites
  124. Recent trends and advancements in the utilization of green composites and polymeric nanocarriers for enhancing food quality and sustainable processing
  125. Retraction
  126. Retraction of “Biosynthesis and characterization of silver nanoparticles from Cedrela toona leaf extracts: An exploration into their antibacterial, anticancer, and antioxidant potential”
  127. Retraction of “Photocatalytic degradation of organic dyes and biological potentials of biogenic zinc oxide nanoparticles synthesized using the polar extract of Cyperus scariosus R.Br. (Cyperaceae)”
  128. Retraction to “Green synthesis on performance characteristics of a direct injection diesel engine using sandbox seed oil”
https://doi.org/10.1515/gps-2023-0237
Schlagwörter für diesen Artikel
Jones reagent; long-chain fatty alcohol; long-chain fatty acid; orthogonal experiment
Creative Commons
BY 4.0

Artikel in diesem Heft

  1. Research Articles
  2. Green polymer electrolyte and activated charcoal-based supercapacitor for energy harvesting application: Electrochemical characteristics
  3. Research on the adsorption of Co2+ ions using halloysite clay and the ability to recover them by electrodeposition method
  4. Simultaneous estimation of ibuprofen, caffeine, and paracetamol in commercial products using a green reverse-phase HPTLC method
  5. Isolation, screening and optimization of alkaliphilic cellulolytic fungi for production of cellulase
  6. Functionalized gold nanoparticles coated with bacterial alginate and their antibacterial and anticancer activities
  7. Comparative analysis of bio-based amino acid surfactants obtained via Diels–Alder reaction of cyclic anhydrides
  8. Biosynthesis of silver nanoparticles on yellow phosphorus slag and its application in organic coatings
  9. Exploring antioxidant potential and phenolic compound extraction from Vitis vinifera L. using ultrasound-assisted extraction
  10. Manganese and copper-coated nickel oxide nanoparticles synthesized from Carica papaya leaf extract induce antimicrobial activity and breast cancer cell death by triggering mitochondrial caspases and p53
  11. Insight into heating method and Mozafari method as green processing techniques for the synthesis of micro- and nano-drug carriers
  12. Silicotungstic acid supported on Bi-based MOF-derived metal oxide for photodegradation of organic dyes
  13. Synthesis and characterization of capsaicin nanoparticles: An attempt to enhance its bioavailability and pharmacological actions
  14. Synthesis of Lawsonia inermis-encased silver–copper bimetallic nanoparticles with antioxidant, antibacterial, and cytotoxic activity
  15. Facile, polyherbal drug-mediated green synthesis of CuO nanoparticles and their potent biological applications
  16. Zinc oxide-manganese oxide/carboxymethyl cellulose-folic acid-sesamol hybrid nanomaterials: A molecularly targeted strategy for advanced triple-negative breast cancer therapy
  17. Exploring the antimicrobial potential of biogenically synthesized graphene oxide nanoparticles against targeted bacterial and fungal pathogens
  18. Biofabrication of silver nanoparticles using Uncaria tomentosa L.: Insight into characterization, antibacterial activities combined with antibiotics, and effect on Triticum aestivum germination
  19. Membrane distillation of synthetic urine for use in space structural habitat systems
  20. Investigation on mechanical properties of the green synthesis bamboo fiber/eggshell/coconut shell powder-based hybrid biocomposites under NaOH conditions
  21. Green synthesis of magnesium oxide nanoparticles using endophytic fungal strain to improve the growth, metabolic activities, yield traits, and phenolic compounds content of Nigella sativa L.
  22. Estimation of greenhouse gas emissions from rice and annual upland crops in Red River Delta of Vietnam using the denitrification–decomposition model
  23. Synthesis of humic acid with the obtaining of potassium humate based on coal waste from the Lenger deposit, Kazakhstan
  24. Ascorbic acid-mediated selenium nanoparticles as potential antihyperuricemic, antioxidant, anticoagulant, and thrombolytic agents
  25. Green synthesis of silver nanoparticles using Illicium verum extract: Optimization and characterization for biomedical applications
  26. Antibacterial and dynamical behaviour of silicon nanoparticles influenced sustainable waste flax fibre-reinforced epoxy composite for biomedical application
  27. Optimising coagulation/flocculation using response surface methodology and application of floc in biofertilisation
  28. Green synthesis and multifaceted characterization of iron oxide nanoparticles derived from Senna bicapsularis for enhanced in vitro and in vivo biological investigation
  29. Potent antibacterial nanocomposites from okra mucilage/chitosan/silver nanoparticles for multidrug-resistant Salmonella Typhimurium eradication
  30. Trachyspermum copticum aqueous seed extract-derived silver nanoparticles: Exploration of their structural characterization and comparative antibacterial performance against gram-positive and gram-negative bacteria
  31. Microwave-assisted ultrafine silver nanoparticle synthesis using Mitragyna speciosa for antimalarial applications
  32. Green synthesis and characterisation of spherical structure Ag/Fe2O3/TiO2 nanocomposite using acacia in the presence of neem and tulsi oils
  33. Green quantitative methods for linagliptin and empagliflozin in dosage forms
  34. Enhancement efficacy of omeprazole by conjugation with silver nanoparticles as a urease inhibitor
  35. Residual, sequential extraction, and ecological risk assessment of some metals in ash from municipal solid waste incineration, Vietnam
  36. Green synthesis of ZnO nanoparticles using the mangosteen (Garcinia mangostana L.) leaf extract: Comparative preliminary in vitro antibacterial study
  37. Simultaneous determination of lesinurad and febuxostat in commercial fixed-dose combinations using a greener normal-phase HPTLC method
  38. A greener RP-HPLC method for quaternary estimation of caffeine, paracetamol, levocetirizine, and phenylephrine acquiring AQbD with stability studies
  39. Optimization of biomass durian peel as a heterogeneous catalyst in biodiesel production using microwave irradiation
  40. Thermal treatment impact on the evolution of active phases in layered double hydroxide-based ZnCr photocatalysts: Photodegradation and antibacterial performance
  41. Preparation of silymarin-loaded zein polysaccharide core–shell nanostructures and evaluation of their biological potentials
  42. Preparation and characterization of composite-modified PA6 fiber for spectral heating and heat storage applications
  43. Preparation and electrocatalytic oxygen evolution of bimetallic phosphates (NiFe)2P/NF
  44. Rod-shaped Mo(vi) trichalcogenide–Mo(vi) oxide decorated on poly(1-H pyrrole) as a promising nanocomposite photoelectrode for green hydrogen generation from sewage water with high efficiency
  45. Green synthesis and studies on citrus medica leaf extract-mediated Au–ZnO nanocomposites: A sustainable approach for efficient photocatalytic degradation of rhodamine B dye in aqueous media
  46. Cellulosic materials for the removal of ciprofloxacin from aqueous environments
  47. The analytical assessment of metal contamination in industrial soils of Saudi Arabia using the inductively coupled plasma technology
  48. The effect of modified oily sludge on the slurry ability and combustion performance of coal water slurry
  49. Eggshell waste transformation to calcium chloride anhydride as food-grade additive and eggshell membranes as enzyme immobilization carrier
  50. Synthesis of EPAN and applications in the encapsulation of potassium humate
  51. Biosynthesis and characterization of silver nanoparticles from Cedrela toona leaf extracts: An exploration into their antibacterial, anticancer, and antioxidant potential
  52. Enhancing mechanical and rheological properties of HDPE films through annealing for eco-friendly agricultural applications
  53. Immobilisation of catalase purified from mushroom (Hydnum repandum) onto glutaraldehyde-activated chitosan and characterisation: Its application for the removal of hydrogen peroxide from artificial wastewater
  54. Sodium titanium oxide/zinc oxide (STO/ZnO) photocomposites for efficient dye degradation applications
  55. Effect of ex situ, eco-friendly ZnONPs incorporating green synthesised Moringa oleifera leaf extract in enhancing biochemical and molecular aspects of Vicia faba L. under salt stress
  56. Biosynthesis and characterization of selenium and silver nanoparticles using Trichoderma viride filtrate and their impact on Culex pipiens
  57. Photocatalytic degradation of organic dyes and biological potentials of biogenic zinc oxide nanoparticles synthesized using the polar extract of Cyperus scariosus R.Br. (Cyperaceae)
  58. Assessment of antiproliferative activity of green-synthesized nickel oxide nanoparticles against glioblastoma cells using Terminalia chebula
  59. Chlorine-free synthesis of phosphinic derivatives by change in the P-function
  60. Anticancer, antioxidant, and antimicrobial activities of nanoemulsions based on water-in-olive oil and loaded on biogenic silver nanoparticles
  61. Study and mechanism of formation of phosphorus production waste in Kazakhstan
  62. Synthesis and stabilization of anatase form of biomimetic TiO2 nanoparticles for enhancing anti-tumor potential
  63. Microwave-supported one-pot reaction for the synthesis of 5-alkyl/arylidene-2-(morpholin/thiomorpholin-4-yl)-1,3-thiazol-4(5H)-one derivatives over MgO solid base
  64. Screening the phytochemicals in Perilla leaves and phytosynthesis of bioactive silver nanoparticles for potential antioxidant and wound-healing application
  65. Graphene oxide/chitosan/manganese/folic acid-brucine functionalized nanocomposites show anticancer activity against liver cancer cells
  66. Nature of serpentinite interactions with low-concentration sulfuric acid solutions
  67. Multi-objective statistical optimisation utilising response surface methodology to predict engine performance using biofuels from waste plastic oil in CRDi engines
  68. Microwave-assisted extraction of acetosolv lignin from sugarcane bagasse and electrospinning of lignin/PEO nanofibres for carbon fibre production
  69. Biosynthesis, characterization, and investigation of cytotoxic activities of selenium nanoparticles utilizing Limosilactobacillus fermentum
  70. Highly photocatalytic materials based on the decoration of poly(O-chloroaniline) with molybdenum trichalcogenide oxide for green hydrogen generation from Red Sea water
  71. Highly efficient oil–water separation using superhydrophobic cellulose aerogels derived from corn straw
  72. Beta-cyclodextrin–Phyllanthus emblica emulsion for zinc oxide nanoparticles: Characteristics and photocatalysis
  73. Assessment of antimicrobial activity and methyl orange dye removal by Klebsiella pneumoniae-mediated silver nanoparticles
  74. Influential eradication of resistant Salmonella Typhimurium using bioactive nanocomposites from chitosan and radish seed-synthesized nanoselenium
  75. Antimicrobial activities and neuroprotective potential for Alzheimer’s disease of pure, Mn, Co, and Al-doped ZnO ultra-small nanoparticles
  76. Green synthesis of silver nanoparticles from Bauhinia variegata and their biological applications
  77. Synthesis and optimization of long-chain fatty acids via the oxidation of long-chain fatty alcohols
  78. Eminent Red Sea water hydrogen generation via a Pb(ii)-iodide/poly(1H-pyrrole) nanocomposite photocathode
  79. Green synthesis and effective genistein production by fungal β-glucosidase immobilized on Al2O3 nanocrystals synthesized in Cajanus cajan L. (Millsp.) leaf extracts
  80. Green stability-indicating RP-HPTLC technique for determining croconazole hydrochloride
  81. Green synthesis of La2O3–LaPO4 nanocomposites using Charybdis natator for DNA binding, cytotoxic, catalytic, and luminescence applications
  82. Eco-friendly drugs induce cellular changes in colistin-resistant bacteria
  83. Tangerine fruit peel extract mediated biogenic synthesized silver nanoparticles and their potential antimicrobial, antioxidant, and cytotoxic assessments
  84. Green synthesis on performance characteristics of a direct injection diesel engine using sandbox seed oil
  85. A highly sensitive β-AKBA-Ag-based fluorescent “turn off” chemosensor for rapid detection of abamectin in tomatoes
  86. Green synthesis and physical characterization of zinc oxide nanoparticles (ZnO NPs) derived from the methanol extract of Euphorbia dracunculoides Lam. (Euphorbiaceae) with enhanced biosafe applications
  87. Detection of morphine and data processing using surface plasmon resonance imaging sensor
  88. Effects of nanoparticles on the anaerobic digestion properties of sulfamethoxazole-containing chicken manure and analysis of bio-enzymes
  89. Bromic acid-thiourea synergistic leaching of sulfide gold ore
  90. Green chemistry approach to synthesize titanium dioxide nanoparticles using Fagonia Cretica extract, novel strategy for developing antimicrobial and antidiabetic therapies
  91. Green synthesis and effective utilization of biogenic Al2O3-nanocoupled fungal lipase in the resolution of active homochiral 2-octanol and its immobilization via aluminium oxide nanoparticles
  92. Eco-friendly RP-HPLC approach for simultaneously estimating the promising combination of pentoxifylline and simvastatin in therapeutic potential for breast cancer: Appraisal of greenness, whiteness, and Box–Behnken design
  93. Use of a humidity adsorbent derived from cockleshell waste in Thai fried fish crackers (Keropok)
  94. One-pot green synthesis, biological evaluation, and in silico study of pyrazole derivatives obtained from chalcones
  95. Bio-sorption of methylene blue and production of biofuel by brown alga Cystoseira sp. collected from Neom region, Kingdom of Saudi Arabia
  96. Synthesis of motexafin gadolinium: A promising radiosensitizer and imaging agent for cancer therapy
  97. The impact of varying sizes of silver nanoparticles on the induction of cellular damage in Klebsiella pneumoniae involving diverse mechanisms
  98. Microwave-assisted green synthesis, characterization, and in vitro antibacterial activity of NiO nanoparticles obtained from lemon peel extract
  99. Rhus microphylla-mediated biosynthesis of copper oxide nanoparticles for enhanced antibacterial and antibiofilm efficacy
  100. Harnessing trichalcogenide–molybdenum(vi) sulfide and molybdenum(vi) oxide within poly(1-amino-2-mercaptobenzene) frameworks as a photocathode for sustainable green hydrogen production from seawater without sacrificial agents
  101. Magnetically recyclable Fe3O4@SiO2 supported phosphonium ionic liquids for efficient and sustainable transformation of CO2 into oxazolidinones
  102. A comparative study of Fagonia arabica fabricated silver sulfide nanoparticles (Ag2S) and silver nanoparticles (AgNPs) with distinct antimicrobial, anticancer, and antioxidant properties
  103. Visible light photocatalytic degradation and biological activities of Aegle marmelos-mediated cerium oxide nanoparticles
  104. Physical intrinsic characteristics of spheroidal particles in coal gasification fine slag
  105. Exploring the effect of tea dust magnetic biochar on agricultural crops grown in polycyclic aromatic hydrocarbon contaminated soil
  106. Crosslinked chitosan-modified ultrafiltration membranes for efficient surface water treatment and enhanced anti-fouling performances
  107. Study on adsorption characteristics of biochars and their modified biochars for removal of organic dyes from aqueous solution
  108. Zein polymer nanocarrier for Ocimum basilicum var. purpurascens extract: Potential biomedical use
  109. Green synthesis, characterization, and in vitro and in vivo biological screening of iron oxide nanoparticles (Fe3O4) generated with hydroalcoholic extract of aerial parts of Euphorbia milii
  110. Novel microwave-based green approach for the synthesis of dual-loaded cyclodextrin nanosponges: Characterization, pharmacodynamics, and pharmacokinetics evaluation
  111. Bi2O3–BiOCl/poly-m-methyl aniline nanocomposite thin film for broad-spectrum light-sensing
  112. Green synthesis and characterization of CuO/ZnO nanocomposite using Musa acuminata leaf extract for cytotoxic studies on colorectal cancer cells (HCC2998)
  113. Review Articles
  114. Materials-based drug delivery approaches: Recent advances and future perspectives
  115. A review of thermal treatment for bamboo and its composites
  116. An overview of the role of nanoherbicides in tackling challenges of weed management in wheat: A novel approach
  117. An updated review on carbon nanomaterials: Types, synthesis, functionalization and applications, degradation and toxicity
  118. Special Issue: Emerging green nanomaterials for sustainable waste management and biomedical applications
  119. Green synthesis of silver nanoparticles using mature-pseudostem extracts of Alpinia nigra and their bioactivities
  120. Special Issue: New insights into nanopythotechnology: current trends and future prospects
  121. Green synthesis of FeO nanoparticles from coffee and its application for antibacterial, antifungal, and anti-oxidation activity
  122. Dye degradation activity of biogenically synthesized Cu/Fe/Ag trimetallic nanoparticles
  123. Special Issue: Composites and green composites
  124. Recent trends and advancements in the utilization of green composites and polymeric nanocarriers for enhancing food quality and sustainable processing
  125. Retraction
  126. Retraction of “Biosynthesis and characterization of silver nanoparticles from Cedrela toona leaf extracts: An exploration into their antibacterial, anticancer, and antioxidant potential”
  127. Retraction of “Photocatalytic degradation of organic dyes and biological potentials of biogenic zinc oxide nanoparticles synthesized using the polar extract of Cyperus scariosus R.Br. (Cyperaceae)”
  128. Retraction to “Green synthesis on performance characteristics of a direct injection diesel engine using sandbox seed oil”
Jetzt anmelden und 20% sparen
Institutioneller Zugang
Wie funktioniert Authentifizierung?
Haben Sie eine Idee, wie wir unsere Website verbessern können?
Bitte schreiben Sie uns.
© 2026 De Gruyter Brill
Heruntergeladen am 20.1.2026 von https://www.degruyterbrill.com/document/doi/10.1515/gps-2023-0237/html
Button zum nach oben scrollen