Ball milling of cellulose in the presence of a catalytic amount of H2SO4 was found to be a promising pre-treatment process to produce butyl glycosides in high yields. Conversely to the case of water, n-butanol has only a slight effect on the recrystallization of ball-milled cellulose. As a result, thorough depolymerization of cellulose prior the glycosylation step is no longer required, which is a pivotal aspect with respect to energy consumption. This process was successfully transposed to wheat straw from which butyl glycosides and xylosides were produced in good yields. Butyl glycosides and xylosides are important chemicals as they can be used as hydrotropes but also as intermediates in the production of valuable amphiphilic alkyl glycosides.
Here we report the screening of various homogeneous acid catalysts in the oligomerization of glycerol at 150 degrees C. Under optimized conditions, a mixture of oligoglycerol with an average degree of oligomerization of 3.4 was obtained at a glycerol conversion of 80%. At such a conversion, the selectivity to oligoglycerols was higher than 90%. Oligoglycerols were then successfully alkylated, offering an attractive route to valuable molecules (biosurfactants or hydrotropes)
In various industrial processes such as petroleum refineries, crude oil must be heated to the required temperature. Here a study of a heat exchanger problem of a catalytic naphtha reforming unit of an SKIKDA refinery (RA1K) is carried out. In this unit the feed (naphtha and recycle gas) is required to enter the first reactor of the reaction section at 471℃, while the feed inlet temperature at the reactor is only 450℃. This problem appeared after starting the unit with a mass flow of 60% of the naphtha. The essential device for heating the charge before entering the reactor is shell-and-tube heat exchanger. In the present study, the Kern method is used to check the heat exchanger in the design and experimental cases. The Aspen HYSYS software has been used to study the influence of various naphtha mass flow rates on the thermal performance of a heat exchanger. The outlet feed temperature was examined for each mass flow rate of naphtha (i.e., 60, 70, 80, 90 and 100%). The simulation results show the important role of the studied parameters in the thermal performance enhancement of heat exchanger, where the case of a mass flow of 60% of the naphtha, the temperature 471℃, provided for by the design, is obtained with an H2/HC ratio of 4.68.
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