Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-I-19KINETICS OF GAS–LIQUID PROCESSES OF OZONATION OFVERATROLE AND ITS DERIVATIVESA.G. Khudoshin, A.N. Mitrofanova, and V.V. LuninDepartment of Chemistry, M.V. Lomonosov Moscow State University,1 Leninsky prosp., 119992 Moscow, Russian Federation.Fax: +7 (495) 939 4575. E-mail: khudoshin@kge.msu.ruInvestigation in the areas of conversion of plant raw materials has intensely beendeveloped in recent years. Lignin is the major component of the plant raw materials. One ofpromising routes is the oxidative destruction of lignin by ozone, which is highly reactivetoward aromatic and unsaturated compounds.The reaction of ozone with lignin is of interest from the viewpoint of designing newtechnologies for delignification and cellulose bleaching, sewage purification in the celluloseand paper industry, and production of valuable products from lignin.Lignin is a natural polyfunctional phenolic polymer with an irregular structure. To studythe kinetics and mechanism of its ozonation, researchers often use compounds modelingdifferent structural fragments of lignin, for example, compounds of the guaiacyl, syringyl, andveratryl series with various substituents. 1,2The purpose of this work is to study the reactivity of lignin and various model lignincompounds. For this purpose, we studied the kinetic regularities of the oxidation with ozoneof soluble sodium ligninsulphanate and the simplest model lignin compounds: phenol,guajacol, veratrole, veratric alcohol, and veratric aldehyde.4.0E-063.0E-062.0E-061.0E-060.0E+00ФенолВератролВератр.Альд.0 0.1 0.2Fig. 2. Plots of the ozone absorption rate vs [ B]0 forphenol (1), veratrole (2), and veratric aldehyde (3).Ozonation was carried out in the newgaslift unit with a natural circulation ofliquid phase at 298 K, an initial ozoneconcentration of 0.9–1.1·10 –3 mol L –1 , andthe flow rate w = 25 L h –1 . The volume ofthe reaction mixture was 0.55 L.The model based on the film theory 3is most convenient to study processesimpeded by mass transfer. Using thismodel, it is assumed that a film is formednear the interface and ozone can penetratethrough the film only due to molecular246