The best results of the waste 1,1,2-trichloroethane dehydrochlorination by 10 wt % NaOH are obtained in temperature 70-80 'C at NaOWl12-TCE molar ratio 1.1:l and flow rate 270 g/(dm3 h). In these conditions 98.3 wt % vinylidene chloride and aqueous layer (13 wt % NaCl + 0.07 wt % NaOH) are obtained. Vinylidene chloride yield is 97.5 mol %.IE940481T @ Abstract published in Advance ACS Abstracts, May 1, 1995.
The influence of technological parameters on dehydrochlorination
of dichloropropanols to epichlorohydrin performed on a reaction-stripping
column and a prereactor was studied. For a fixed flows of dichloropropanols
solution, lime milk solution, and steam through the column, the conversion
of dichloropropanols and the yield of epichlorohydrin were calculated.
The influence of an excess of lime milk solution, recirculation of
the water layer of the distillate from the column, the rate of steam
flow through the column, and an excess of calcium hydroxide over dichloropropanols
on the course of the process was studied. Moreover, the effects of
the reaction time and temperature of the prereactor were tested.
Carbamazepine (CBZ), nonbiodegradable pharmaceutical residue, has become an emerging pollutant in several aquatic environments. The effectiveness of the mixture of soil and fly ash (FA) in adsorbing CBZ from aqueous solution has been studied as well as agitation time, FA content, initial CBZ concentration and desorption as a function of FA content. The adsorption kinetics fits a hyperbolic or pseudo-second-order model. The maximum adsorbed amounts for natural soil and a mixture of soil/FA ranged from 77 to 158 mg kg(-1). Rate constants were considered relatively low (4.15-15.59 × 10(-4) kg mg(-1) min). The logarithmic form of the Freundlich equation gave a linearity and the Kf constants increased with the increase of FA content in adsorbent mixtures and with the affinity between the adsorbent surface and adsorbed solute. The mean removed amounts of CBZ by adsorption batch experiments in a soil mixture with 30% FA content were up to 92.8% for coal FA and 33% in natural soil. This work proved that the mixture of the coal FA and soil can be used as an efficient adsorbent material for removal of CBZ from water.
The results of continuous dehydrochlorination of an 88 wt % aqueous solution of 1,3-dichloropropan-2-ol (13DCP2OL) to epichlorohydrin (EPI) are presented. The dehydrochlorination was carried out in the reaction-stripping column system. The influence of the following parameterslime milk concentration, the molar ratio of Ca(OH) 2 /13DCP2OL, the rate of steam flow through the column, pressure, changes in loading of reaction-stripping column, reaction time in a prereactor and reactor on the conversion of 13DCP2OL, and the selectivity of transformation to EPIwere studied. In one series of investigations, EPI was collected from the column in the form of distillate, in the second one, from the distillation reboiler under the column. It was evaluated which methods of collection of EPI distillate are more favorable. The technological parameters were provided for the operation of the reaction-stripping system, which allow one to obtain EPI with the selectivity close to 100%, simultaneously giving high conversion (90%) of 13DCP2OL.
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