Band 2, Heft 2

Current developments in the field of micro-nano technologies in the Middle East and North Africa (MENA) region are highlighted. Firstly, the scientific outcome of micro-nano technologies from the MENA region is analyzed. Egypt and Saudi Arabia are the leading countries, with >50% of the total MENA publications. More than 50% were joint publications with France and the United States as the major partners. Secondly, different kinds of existing initiatives to develop and support micro-nano technologies in the MENA region are presented. The working principle of current respective initiatives is demonstrated. Despite the importance of these initiatives, they are fragmented and lack a regional framework and a common goal. Thirdly, therefore, a recommendation is suggested to create a platform and a road map for boosting the development of micro-nano technologies in the MENA region.

n -Butanol is an important bulk chemical and a promising potential fuel additive. An alternative way to the chemical production of biobutanol from crude oil is the fermentation of biomass. However, the main drawback of this process is the toxicity of n -butanol towards the microorganisms resulting in a limited productivity. Additionally, high purification costs occur due to an energy-intensive distillation step which is used, up to now, as purification technology for the recovery of n -butanol. Therefore, alternative separation processes are discussed in this study. Extraction and pervaporation are two unit operations with high potential to overcome this problem. Because of their tuneable properties, the use of ionic liquids as extraction solvents for n -butanol recovery is a promising option; however, their economic potential is not obvious because of the relatively high costs. On the basis of those two unit operations, different potential processes to separate biobutanol from water are modelled using experimental data. Cost estimations result in purification costs of €0.230 kg -1 to €0.296 kg -1 n -butanol, which accounts for 20%–27% of the n -butanol market price in 2012.

The biochemical production of n- butanol by fermentation is an interesting option for the sustainable production of a chemical that can be used as a fuel additive or solvent. However, n- butanol is toxic towards the production organisms, resulting in low concentrations of biobutanol in the aqueous fermentation broth. Therefore, conventional purification by distillation is very energy intensive. Extraction with ionic liquids and pervaporation as alternative separation technologies are two promising options for energy-efficient n- butanol recovery. These processes are analysed on detailed economics, including the influence of the uncertainty of the used model parameters and the sensitivity of the production costs to model parameters and design variables. It is shown that the costs for n- butanol purification by means of distillation are strongly dependent on the costs for thermal energy. For extractive recovery, the solubility of the extraction solvent in the raffinate is one of the main cost drivers as it affects the solvent loss. The costs of the pervaporation-based recovery mainly depend on the price for the membranes and are strongly dependent on the permeate fluxes. For all processes, the feed concentration has a noteworthy effect on the total downstream costs. This study allows not only an analysis of existing technologies but also helps to guide future research.

An effective hydrolysis method for recovering oligosaccharides directly from lignocellulosic biomass has been investigated. Formic acid was selected as a hydrolysis reagent, due to its high acidity in organic acids. The degrees of cellulose hydrolysis and lignin elution were determined by the combination of the reaction temperature and formic acid aqueous solution concentration. We successfully obtained approximately 47 wt% of oligosaccharides, keeping the minimum lignin elution at 150°C and with 25 vol% formic acid aqueous solution concentration. Such a high yield of oligosaccharides was due to the relaxation of biomass structure. Furthermore, by diluting the formic acid aqueous solution concentration, or evaporating the solution, lignin can be separated from the oligosaccharides completely as deposits. Finally, two options for the efficient recovery of saccharides have been proposed.

A simple and highly efficient procedure for the synthesis of 2 H -chromen-2-ones via von Pechmann condensation, involving the grinding of different phenols and β-ketoesters in the presence of silica supported sulfuric acid at room temperature, under solvent free conditions, has been described.

The objective of microfluidic droplet flow is the control and manipulation of fluids on the sub-mm scale. This article describes the microfluidic droplet flow in a liquid-liquid contacting unit utilizing microchannels and millichannels and their counter-current arrangement. A contacting module consists of a droplet generator, a channel to enable an intensified mass transfer between two fluids and a liquid-liquid separation device. Experiments were performed with deionized water as a continuous phase and various organic solvents as a dispersed phase. The organic droplets are generated by direct coflowing injection through a needle located in the center of the microchannel. Droplet generation and flow patterns were optically investigated in straight and winding channels. The adjacent separation unit continuously splits the organic, dispersed phase. The combined effects of gravity, wetting characteristics of the wall material and capillary forces nearly completely separate the two fluids over a wide range of flow rates. Based on the mixer-settler system, a microfluidic extraction unit is proposed that enables a multistage counter-current arrangement.