SU654600A1 - Method of obtaining dichlorbenzols - Google Patents

Description

(54) METHOD FOR PRODUCING DICHLOROBENZENES

The invention relates to a process for the preparation of benzene chloro derivatives, in particular dichlorobepzols, which are used in the manufacture of pre-chemicals, for example, as an insecticide and a disinfectant. The known method of oxidized chlorination of benzene at 200-400 ° C with a mixture of hydrogen chloride and air in the presence of a catalyst — copper chloride, alkali metal chloride, and rare-earth metal chloride — is on silica gel | 1. Dichlorobepzols are formed as by-products (3-4 wt.%). The closest to the described technical result and the achieved result is the method of obtaining dichlorobenzenes by the interaction of chlorobenzene with hydrogen chloride or chlorine and oxygen-containing gas (air) in the presence of a catalyst containing copper chloride and lithium chloride at a 5: 1 weight ratio on a carrier - α-alumina 2. At 200 ° C, the conversion of chlorobenzene is 14% by weight. Ratio of isomers of steam: ortho 3.3: 1. However, this method gives a low yield of dichlorobenzenes, especially the para-isomer (9%) of the theory on the taken chlorobenzene ;. At low temperatures (on the order of), a low dichlorobenzene yield is obtained on this catalyst. As the temperature increases, a mixture of dichlorobenzenes and trichlorobenzenes is formed, and the formation of the ortho-isomer also increases. Under comparable conditions, the largest yield of dichlorobenzenes (in% of the theory on chlorobenzene taken) does not exceed 61%, and the para isomer is 45.22% (the temperature of the comparative experiment is 290 ° C). With a further increase in temperature, process performance is further reduced due to an increase in the proportion of higher benzene polychloride. In order to increase the yield of dichlorobenzenes and mainly to produce para-dichlorobenzene, a method for the preparation of dichlorobenzenes is proposed, consisting in that benzene or chlorobenzene is reacted with hydrogen chloride or chlorine and oxygen-containing gas at a temperature of 285-295 ° C in the presence of a catalyst containing copper chloride, lithium chloride and additionally lead oxide with a weight ratio equal to 1: 0.5-0.7: 0.02-0.04, respectively, on an aluminosilicate carrier.

Distinctive features of the described method are the use of a catalyst containing additionally lead oxide, with a weight ratio of copper chloride, lithium chloride and lead oxide 1: 0.5– 0.7: 0.02–0.04, and the use of aluminosilicate as a carrier for the catalyst carrier. Usually the process is carried out at a contact time of 5-6 seconds.

On a catalyst of this composition at 290 ° C, contact time of 6 seconds, the molar ratio of chlorobenzene: hydrogen chloride: oxygen 1: 1: 0.5 reagents were obtained, 37 290 3.12

Hporbenzop NSR 2,590,84

0.24,295 3.58

Khporbenzoa Khpor 2.980.91 31 EnsopSB 0.88 2853.76 2.152.12 1.84 2857.41 15.65 8 Benzene 4.474.24 Note:

The following results: dichlorobenzene yield (% of theory for chlorobenzene taken) 90.52, para-dichlorobenzene 73.72, conversion of chlorobenzene 92.2 bes.%, conversion of hydrogen chloride 93.62 wt.%, oxygen conversion 97 , 13 wt.%. The selectivity for dichlorobenzene 98,02 wt.%, The selectivity for para-dichlorobenzene 80,60 wt./about.

When benzene is used as a raw material, the process indicators (per pass) are lower (dichlorobenzenes yield 72.08%, para-isomer yield 55.02%).

. If an equimolar mixture of chlorobenzene and benzene is taken, the process indicators are intermediate. Output

Oxidative chlorination

- 8O, 11 17.82 1.75 0.32

- 78.25 17.05 4.0 0.70 1) The contact time in the experiment is 2 5 seconds, in the rest - 6 seconds. 2) For the data presented in the form of fractions, the numerator in the numerator is 19.20 58.45 12.9 O, 9.21 0.24 62.8 O, 13.50 7.44 0.61 dichlorobenzenes (per pass) 74.08 weight. ° / o, para-dichlorobenzene 63.25 wt. ° / o. The process may use chlorine or mixtures of hydrogen chloride and chlorine instead of hydrogen chloride. Example 1. As the carrier using aluminosilicate. Grain size 2-3 mm. Before preparing the catalyst, the support is calcined for 4 hours at 300 ° C, cooled and weighed. Then it is immersed in a solution containing the calculated amount of salts CuCla, LiCl and Pb (CH 3 COO) 2, which is evaporated with constant stirring in a water bath. The final drying of the catalyst is carried out at 120 ° C to

petrol containing raw materials

92.20 93.62 97.13 98.02 80.60

93.02 97.32 97.47 9b, O4 78.8887.72 71.85

99.21 94.95 91.50 68.6356.2268.08 55.02

91.54 92.16 93.07 81.2269.4574.08 63.25

76.OO 92.22

96.62 77.61 59.54

99.10 76.23 62.3175.90

99.50 99.90

93.15 79,7293.25

100

99.40 99.90

99.42 75.93 62.2075.42 62.19

93.00 79.42 93.00 79.42 100

99.30 99.70 99.60 74.52 61.3074.10 61.16

10093, OO 79,2592,90 79,05 means the indicator for the passage, and in the denominator - taking into account

90.52 73.72

61.00 45.22

Claims (2)

62.25 79.72 constant weight. The composition of the finished catalyst is characterized by the amount of copper, the total amount of salts, expressed in ° / o (wt.), As well as the molar ratio of the salts introduced. The molar ratio of SiC1: IC1: Pb (CH3COO) is 1: 0.5: 0.03. The amount of Cu is 8% by weight. For the preparation of the catalyst, 16.9 w / o CuCU, 2.671% w / w LiCl, 1.25% w / w Pb (CH 2 COO) a are used. Sheath, its amount of salts is 20.871 w / v. The prepared catalyst is activated with a gas mixture of hydrogen chloride and oxygen in the ratio HC1: Og 4: 1 P 00 ° for 3-5 h. Recycle of unreacted CF. The oxidative chlorination of chlorobenzene is carried out in the vapor phase in a glass flow reactor with a diameter of 25 mm and a length of 300 mm, equipped with a pocket for thermo-filters and a filter in the lower tube to hold the catalyst bed. The upper part, made of broken quartz glass, serves as an evaporator of chlorobenzene and a preheater of the source gases. To provide isothermal conditions, the catalyst in the reactor is mixed with silicon carbide in a 1: 1 weight ratio. At a thermal temperature of 290 ° С, the contact time is 6 seconds, initial reagents with a molar ratio of chlorobenzene: HCI: oxygen 1: 1: 0.5 are fed into the reactor. The time of the experiment is 10 hours. The speed of the reagents, g / h: chlorobenzene 2.59; HCI 0.84; Og 0.37. The reaction gases are condensed in traps at a temperature of from -20 to -15 ° C. The unreacted gases after washing with water from HCI enter the gas meter. Under the above conditions, 33.76 g of catalyst is obtained, which is distilled on a distillation column. 30.56 g of dichlorobenzenes are obtained, of which 25 g of para-dichlorobenzene with m.p. 53 ° C. The reaction products are also identified by gas chromatography and IR spectroscopy. Example 2. The test procedure is similar to the example. Time, contact 5 seconds. The catalyst composition of CuC 2: LiCl: PbO 1: 0.5: 0.022 on aluminosilicate. The molar ratio of the reagents chlorobenzene: chlorine: oxygen 2: 1: 0.5. The time of the experiment is 1 hour. Example 3. The experimental procedure is analogous to Example 1. The catalyst of the composition CuCl2: LiCl: PbO 1: 0.5: 0.022 on silica-alumina. The molar ratio of benzene reagents, chlorine hydrogen: oxygen - 1: 2: 1. Time opt) 1ta 1 h. Example 4. The procedure of the experiment is similar to the example. The catalyst of composition ССС12: 1lС1: РЬО 1: 0.5: 0.022 on aluminosilicate. A mixture of benzene and chlorobenzene is used as a raw material. The molar ratio of benzene: chlorobenzene: hydrogen chloride: oxygen 1: 1: 1: 1.5. Experience time 1 hour. Example 5. (Comparative according to a known method). The procedure is carried out as in Example 1. The catalyst of the composition CuCls: LiCl 5: 1. The carrier is alumina. The molar ratio of the reagents chlorobenzene: chlorine hydrogen: oxygen 1: 1: 0.5. The time of the experiment is 1 hour. Example 6. The procedure of the experiment is similar to Example 1. Catalyst of the composition SiC1: IC1: PHO 1: 0.7: 0.04 on aluminosilicate. The molar ratio of reagents benzene: hydrogen chloride: oxygen 1: 2: 1. Time experience 1h. After isolation, unreacted chlorobenzene is again subjected to oxidative chlorination under the same conditions. An additional amount of the para-isomer is obtained. Example 7. The procedure of the experiment is similar to example 6. Catalyst composition CuCl.:LiCl:PbO 1: 0.7: 0.06 on aluminosilicate. Example 8. The test procedure is similar to Example 6. The catalyst of the composition CuCla: LiCl: PbO 1: 0.9: 0.04 on aluminosilicate. The conditions and results of the experiments are tabulated. DETAILED DESCRIPTION OF THE INVENTION The method for producing dichlorobenzenes by reacting benzene or chlorobenzene with hydrogen chloride or chlorine and oxygen-containing gas meters at elevated temperatures in the presence of a catalyst containing copper chloride and lithium chloride on a carrier, characterized in that, in order to increase the yield of the target product and preferentially produce steam -dichlorobenzene, as the catalyst used is a catalyst containing additionally lead oxide with a weight ratio of copper chloride, lithium chloride and lead oxide 1: 0, 5-0.7: 0.02-0.04, an aluminosilicate carrier is used as the carrier and the process is carried out at a temperature of 285-295 ° C. Sources of information taken into consideration at the examination 1.Patent of the USSR 180150, C 07 C 17/02, 11.11.61. 2.Ind. ang. Eng. Chem. Proc. Des. and. Dev. S. Altuglu, R. W. Roberts, Oxychlorination Kinetics of Chlorobenzene, 12, No. 2, 1973 p. 160-164.