DEPENDENCE OF Cr-Cu-O CATALYSTS ACTIVITY IN THE REACTION OF ETHANOL DEHYDROGENATION ON THEIR PHASE COMPOSITION

The work deals with the reaction of ethanol conversion over chromium copper binary oxide catalysts. It showed that acetaldehyde is the main product of the ethanol conversion reaction. As the temperature rises, the direction of the ethanol conversion reaction shifts toward dehydration of ethanol into ethylene. Studies revealed that the atomic ratio of chromium to copper in the composition of the catalyst also has a strong effect on the activity of chromium-copper oxide catalysts. It established that samples with high chromium content in the composition of the catalyst display the greatest activity in the reaction of acetic aldehyde formation. So, on the sample Cr-Cu = 6-4, the yield of acetaldehyde reaches 82.5% with a selectivity of 97.6%. X-ray studies found that Cr-Cu-O catalysts consist mainly of initial oxides and in some samples indicate the chemical compound. X-ray studies showed that as the copper content decreases, the degree of crystallinity increases in the studied catalytic system. Comparison of the activity of Cr-Cu-O catalysts with their crystallinity degree revealed that the rise in crystallinity degree of chromium-copper oxide catalysts leads to the increase of acetic aldehyde yield and its selectivity in the ethanol conversion reaction.

CATALYTIC SYNTHESIS OF A LINE BY ACETYLENE HYDRATION

Acetone is a valuable chemical product. It can be obtained by oxidative dehydrogenation of isopropyl alcohol, oxidation of propylene, decomposition of acetic acid and ethyl alcohol, oxidation of cymene and others. Among the known processes for the production of acetone, the most promising is the synthesis by hydration of acetylene in the presence of catalysts. The advantage of this method is the possibility of carrying out the process in existing plants for the production of acetic aldehyde. On the other hand, the process of simultaneously producing acetaldehyde and acetone under the influence of multifunctional catalysts and carrying out the process using flexible technology is promising. The vapor-phase hydration of acetylene with the formation of acetone on polyfunctional catalysts was studied. Process parameters are found that provide acetone with high selectivity and acetylene conversion. At present, acetic aldehyde is mainly obtained by two methods - hydration of acetylene and oxidation of ethylene. The process of hydration of acetylene to acetic aldehyde in the presence of catalysts has been studied quite well. Numerous catalysts have been proposed for this process. Among the known catalysts for hydration of acetylene to acetic aldehyde, the most active was the cadmium calcium phosphate catalyst (CCF), which is recommended for industrial use. However, cadmium calcium phosphate catalyst is not without drawbacks. The average yield of acetaldehyde in one pass of acetylene does not exceed 7.0%. The CCF catalyst is very sensitive to temperature changes, its service life before regeneration does not exceed 72-76 hours. Keywords: acetone, propylene, hydration process, catalyst, crosslinking, multifunctional properties.

Enzym Methods in Wine Analysis

In our laboratory for special determinations BOERINGER-MANNHEIM's enzyme-test combinations have been used for 10 years. Our present work deals with the practical aspects of the enzymatic determination of so important wine components like L-malic, L-lactic and citric acid, glycerol, D-gluconic acid, D-sorbitol, acetic aldehyde and D-glucose to D-fructose (G/F) ratio. Whenever possible, the results arc compared to the results of other methods (spectrophotometry, gas chromatography, polarimetry) used at our department.