Method for combined production of benzyl alcohol, benzaldehyde and benzoic acid through oxidizing toluene

A technology for benzaldehyde and benzyl alcohol, applied in the field of preparation of aromatic compounds, can solve the problems of polluted product quality, low production efficiency, difficult products, etc., and achieves the effects of safe separation process, reduced generation probability, and improved utilization rate

Active Publication Date: 2016-05-25
山东友道化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the conversion rate of toluene was 4.83%, the selectivity of benzaldehyde and benzyl alcohol was 38.8% and 20.5% respectively, and the total selectivity was 59.3%. The disadvantage was that the reaction conversion rate was low, so that the production efficiency was low. There is still a large room for improvement in the selectivity, and more importantly, 10.5% of other unknown by-products are generated during the reaction
This method relies on the oxygen-containing gas to disperse through the small holes on the tower-shaped sieve plate for many times to react with the raw material. The principle that oxygen can be absorbed with high efficiency improves the production efficiency, but the selectivity of benzaldehyde and benzyl alcohol in the product is generally lower than that of 30%, and there are nearly 10% unknown heavy component by-products
CN1522996A has further developed the disclosed method of CN1296937A. After adding benzaldehyde as initiator and optimizing the reaction conditions, from the effects of its examples, the selectivity of benzaldehyde and benzyl alcohol can reach nearly 90%, but there are still nearly 10% selectivity. % of unknown heavy component by-products
This method is the same as the sh

Method used

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  • Method for combined production of benzyl alcohol, benzaldehyde and benzoic acid through oxidizing toluene
  • Method for combined production of benzyl alcohol, benzaldehyde and benzoic acid through oxidizing toluene
  • Method for combined production of benzyl alcohol, benzaldehyde and benzoic acid through oxidizing toluene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0067] The catalyst dissolved in fresh toluene added to the system is HfO 2 , N-hydroxyl o-sulfonyl benzamide, metal phthalocyanine (R) with general formula (IV) structure 1 = H, R 2 =F, M=Fe) and metalloporphyrins (R 1 =R 3 =OH, R 2 =H, M=Ru) with a total concentration of 600 ppm. When the device is in steady state operation, the flow rate of fresh toluene added to the oxidation reactor is 6.1mL / h. At this time, the average residence time of the oxidation reactor in terms of liquid phase substances is 1.6h, and the pressurized pure oxygen is continuously introduced into the oxidation reactor. In the reactor, the reaction temperature of the system is maintained at 179° C., and the reaction pressure is 0.8 MPa. The volume ratio of the amount of water added to the hydrolysis reactor to the oxidation reaction solution entering the hydrolysis reactor is 0.33:1, and pressurized pure oxygen is continuously introduced to maintain the reaction temperature in the hydrolysis reacto...

Embodiment 2

[0069] The catalyst that dissolves in the fresh toluene that adds in the primary oxidation reactor is the metal phthalocyanine (R with general formula (IV) structure 1 = H, R 2 =CH 3 CH 2 , M=Co), the total concentration is 45ppm. When the device is in steady state operation, the flow rate of fresh toluene added to the oxidation reactor is 11.7mL / h. At this time, the average residence time of the oxidation reactor in terms of liquid phase substances is 2.4h, and the pressurized pure oxygen is continuously introduced into the oxidation reactor. In the reactor, the reaction temperature of the system is maintained at 185° C., and the reaction pressure is 2.2 MPa. The volume ratio of the amount of water added to the hydrolysis reactor to the oxidation reaction liquid entering the hydrolysis reactor is 0.90:1, and the reaction temperature in the hydrolysis reactor is maintained at 110°C, and the reaction pressure is 2.0MPa. At this time, the liquid phase residence time in the hy...

Embodiment 3

[0071] The catalyst dissolved in fresh toluene added to the primary oxidation reactor is Mn(Ac) 2· 4H 2 O, metal phthalocyanine (R) with general formula (IV) structure 1 = NO 2 , R 2 =H, M=Co), the metalloporphyrin (R 1 =R 3 = H, R 2 =CH 3 CH 2 , M=Cu) mixture with a total concentration of 120ppm. When the device is in steady state operation, the flow rate of fresh toluene added to the oxidation reactor is 15.3mL / h. At this time, the average residence time of the oxidation reactor in terms of liquid phase substances is 1.5h, and the pressurized pure oxygen is continuously introduced into the oxidation reactor. In the reactor, the reaction temperature of the system is maintained at 175° C., and the reaction pressure is 0.7 MPa. The volume ratio of the amount of water added to the hydrolysis reactor to the oxidation reaction solution entering the hydrolysis reactor is 0.28:1, and pressurized pure oxygen is continuously introduced to maintain the reaction temperature in ...

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Abstract

The invention discloses a method for combined production of benzyl alcohol, benzaldehyde and benzoic acid through oxidizing toluene. The method comprises the following steps: 1, oxidizing: continuously introducing toluene, a catalyst and an oxygen-containing gas to an oxidation reactor, and reacting to obtain an oxidation reaction solution; 2, hydrolyzing: continuously introducing the oxidation reaction solution to a hydrolysis reactor, continuously adding water to the hydrolysis reactor, and reacting to obtain a hydrolysis reaction mixture; 3, carrying out liquid-liquid layering: continuously adding the hydrolysis reaction mixture to a liquid-liquid layering device to obtain an upper layer oil phase containing toluene, benzyl alcohol and benzaldehyde and a lower layer water phase containing benzyl alcohol, benzaldehyde and benzoic acid; and 4, carrying out product separation: rectifying the upper layer oil phase to obtain incompletely reacted toluene, benzyl alcohol and benzaldehyde products, and cooling and crystallizing the lower layer water phase, and filtering the cooled and crystallized lower layer water phase to obtain a filtrate and a benzoic acid product. The method has the advantages of high raw material conversion rate, few byproducts, good selectivity of target products, and environmental protection.

Description

technical field [0001] The invention relates to a method for preparing aromatic compounds, in particular to a method for co-producing benzyl alcohol, benzaldehyde and benzoic acid by oxidation of toluene. Background technique [0002] Benzoic acid, benzyl alcohol and benzaldehyde are important fine chemical products. Benzoic acid is one of the important raw materials in the organic synthesis industry. It can be used as dye intermediates, mordants, plasticizers, diuretics, food preservatives, etc., and has very considerable market prospects. Benzaldehyde and benzyl alcohol are the most important aromatic aldols in industry, widely used in medicine, pesticide, food and other fields. Industrially, benzoic acid is produced by the direct oxidation of toluene, as described in EP0036233, CN101613269A, etc., and a small amount of byproducts such as benzaldehyde and benzyl alcohol are also generated. However, the selectivity of benzyl alcohol and benzaldehyde is very low, and the p...

Claims

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Application Information

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IPC IPC(8): C07C27/12C07C27/26C07C27/34C07C51/265C07C51/42C07C51/48C07C51/487C07C63/06C07C45/36C07C45/78C07C45/80C07C47/54C07C29/50C07C29/74C07C29/86C07C29/88C07C33/22
CPCC07C29/50C07C29/74C07C29/86C07C29/88C07C45/36C07C45/78C07C45/80C07C51/265C07C51/42C07C51/48C07C51/487C07C63/06C07C47/54C07C33/22
Inventor 王勤波熊振华陈楚雄
Owner 山东友道化学有限公司
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