III International Conference

ELECTROCATALYTIC REDUCTION OF NITROBENZOIC ACID ONCATALYSTS − METALS OF s- AND d-GROUPSPP-II-86Muldakhmetov M.Z., Do S.V., Kulakova E.V., Ivanova N.M., Kirilyus I.V., Bekenova U.B.Institute of Organic Synthesis and Coal Chemistry of Kazakhstan Republic, Karaganda,KazakhstanE-mail: dovs2003@mail.ruThe researches of electrochemical and electrocatalytic reduction process of nitrobenzoicacid to aminobenzoic one on the cathode activated by skeletal and electrochemical powderscatalysts – the metals of s-(Cu, Zn) and d-groups (Ni, Fe, Co) were carried out.Due to the wide practical application of aminobenzoic acid (in quality components ofaromatic substances, dyes and medicinal preparations) much attention is given todevelopment of the most effective methods of its synthesis. The aminobenzoic acid is aproduct of hydrogenation of nitrobenzoic acid (OH–C 6 H 5 –NO 2 , 1).The experiments on reduction of para-isomer of 1 were conducted in еlectrocatalytic cellon the copper cathode (surface area 0,05 м 2 ) activated by skeletal and electrochemical powderscatalysts (0,25 g) – the d- and s-metals (Ni, Zn, Cu, Co, Fe); at a current density of 2 kA/m 2 ,temperature 30 o С. The anolyte quality of 20 wt % solution of NаОН (60 ml), catholyte of2 wt % solution of NаОН (60 ml), the quantity of 1 - 1,49 g (0,0089 mol) calculated on theFaradey law by absorption 600 ml of hydrogen were used. The results are given in Table.Table. Comparative results of reduction of nitrobenzoic acid on various catalystsCatalyst W av ., ml Н 2 /min Consumption of Н 2 , % η, %Without the catalyst 5,48 79,8 85,4Ni sk. 6,6 100 94,5Cu sk. 6,3 100 90,4Zn sk. 6,75 100 97,8Co sk. 6,35 100 87,9Fe sk. 5,5 90,8 79,8Cu el.p. 6,6 97,2 98Zn el.p. 6,6 100 97,1W av. – the average rate of process (50 % of absorption of hydrogen pays off for the period);η – operating ratio of hydrogen.According to the data electrochemical reduction proceeds not up to the end and withlower rate and operating ratio of hydrogen, than in processes with the use of the catalysts.Compare the activity of skeletal catalysts, the process of hydrogenation on skeletal ironproceeds with the least intensity, and with greatest - on Zn and Ni catalysts. As a whole, therate of electrocatalytic reduction of 1 grows in a line of skeletal catalysts: Fe < Cu < Co < Ni< Zn. Among the used electrochemical powder catalysts zinc shows the larger activity, thancopper. For electrocatalytic reduction of 1 it can be recommended the Reney nickel, which isconvenient in employment and shows high catalytic activity.319