Catalytic conversion of sodium lignosulphonate to vanillin –engineering aspects. Part 1 Effect of processing conditionson vanillin yield and selectivity

The commercial production of vanillin from sodium lignosulfonate under highly alkaline conditions, catalyzed by Cu2+ at elevated temperature and pressures up to 10 bar, has been simulated in a 3-L stirred reactor. Initially, the process was operated in the presence of nitrogen in dead-end mode, and it was shown that vanillin and vanillic acid were formed by hydrolysis at temperatures of 120, 140, and 160 °C. At the two higher temperatures, the amount of vanillin produced was the same. Subsequently, experiments were conducted at the same elevated pressures and temperatures with addition of air or oxygen-enriched air once the temperature in the reactor had reached temperatures similar to those used when only hydrolysis occurred. In this case, the concentration of vanillin at 140 and 160 °C was equal to that due to hydrolysis, and the subsequent 2-fold increase was due to oxidation. In addition, both vanillic acid and acetovanillone (which has rarely been reported) were produced, as was hydrogen. Thus, for the first time, it has been shown that the production of vanillin (and other compounds) from sodium lignosulfonate at elevated temperatures involves hydrolysis and oxidation, with hydrolysis starting at just above 100 °C, that is, much lower than has previously been reported. Approximately 50% is produced by each mechanism. In addition, the orders of the reactions of the different steps were estimated, and the reaction mechanisms are discussed.

Development of a heterogeneous catalyst for lignocellulosic biomass conversion:Glucose dehydration by metal chlorides in a silica-supported ionic liquid layer

An attempt is made to immobilize the homogeneous metal chloride/EMIMCl catalyst for glucose dehydration to 5-hydroxymethylfurfural. To this end, ionic liquid fragments were grafted to the surface of SBA-15 to generate a heterogenized mimick of the homogeneous reaction medium. Despite a decrease in the surface area, the ordered mesoporous structure of SBA-15 was largely retained. Metal chlorides dispersed in such ionic liquid film are able to convert glucose to HMF with much higher yields as is possible in the aqueous phase. The reactivity order CrCl > AlCl > CuCl > FeCl is similar to the order in the ionic liquid solvent, yet the selectivity are lower. The HMF yield of the most promising CrCl-Im-SBA-15 can be improved by using a HO:DMSO mixture as the reaction medium and a 2-butanol/MIBK extraction layer. Different attempts to decrease metal chloride leaching by using different solvents are described. © 2013 American Institute of Chemical Engineers Environ Prog.

A low temperature, isothermal gas-phase system for conversion of methane to methanol over Cu-ZSM-5

A low temperature, isothermal, gas-phase, recyclable process is described for the partial oxidation of methane to methanol over Cu–ZSM-5. Activation in NO at 150 °C followed by methane reaction and steam extraction (both at 150 °C) allowed direct observation of methanol at the reactor outlet.

High-speed conversion of xylose to l-lactate by electrodialysis bioprocess

Conversion of xylose to l-lactate was carried out by Lactococcus lactis IO-1 using an electrodialysis bioprocess (ED-BP). At 50 g l -1 xylose, the ED-BP was already complete in half the time (32 h) taken by the control culture without electrodialysis (>60 h). At 80 g l -1 xylose, the control culture was unable to consume >50 g l -1 xylose, whereas the ED-BP consumed 75 g l -1 xylose in 45 h. Thus, the simultaneous removal of lactate and acetate by ED-BP was associated with high-speed l-lactate production, increased xylose consumption and an increased l-lactate production. Copyright (C) 1998 Elsevier Science B.V.

CHROMIUM(II)-MEDIATED CONVERSION OF ALPHA,BETA-UNSATURATED ALDEHYDES TO CYCLOPROPANOLS

Chromium(II) chloride converts alpha,beta-unsaturated aldehydes to the corresponding cyclopropanols.

CO2 capture and electrochemical conversion using superbasic [P66614][124Triz]

The ionic liquid trihexyltetradecylphosphonium 1,2,4-triazolide, [P66614][124Triz], has been shown to chemisorb CO2 through equimolar binding of the carbon dioxide with the 1,2,4-triazolide anion. This leads to a possible new, low energy pathway for the electrochemical reduction of carbon dioxide to formate and syngas at low overpotentials, utilizing this reactive ionic liquid media. Herein, an electrochemical investigation of water and carbon dioxide addition to the [P66614][124Triz] on gold and platinum working electrodes is reported. Electrolysis measurements have been performed using CO2 saturated [P66614][124Triz] based solutions at −0.9 V and −1.9 V on gold and platinum electrodes. The effects of the electrode material on the formation of formate and syngas using these solutions are presented and discussed.