A method for safely synthesizing propylene oxide and coproducing adipic acid

Abstract

Belonging to the technical field of organic chemical industry, the invention relates to a method for safe synthesis of propylene oxide and co-production of adipic acid. The method for safe synthesis of propylene oxide and co-production of adipic acid provided by the invention utilizes a pressurized rectification device to recover propylene, at the same time utilizes hydrogen peroxide decomposed oxygen to oxidize cyclohexanone for preparation of adipic acid and removal of oxygen in the gas phase, thus not only realizing co-production of high value-added adipic acid, but also ensuring the intrinsic safety of the process. At the same time, propylene and nitrogen in tail gas are recycled and reused, thereby realizing recovery and utilization of resources. The method provided by the invention has the advantages of high atom utilization, intrinsic safe process, rational utilization of resources, low VOC emission, etc.

Description

technical field [0001] The invention belongs to the technical field of organic chemical industry, relates to a method for safely synthesizing propylene oxide and co-producing adipic acid, more specifically, relates to a method for preparing propylene oxide by direct oxidation of hydrogen peroxide, which utilizes peroxidation in the epoxidation reaction Oxygen oxidation of cyclohexanone produced by hydrogen decomposition not only prepares adipic acid with high added value, but also effectively removes oxygen in the system, ensuring the intrinsic safety of the process. Recycling, among which propylene oxide synthesis: yield over 90%, pressurized rectification propylene recovery rate over 99%; adipic acid synthesis: oxygen conversion rate over 99.5%, selectivity over 80%, and the final tail gas is all compressed and returned to the ring Oxypropane synthesis to achieve complete recovery of propylene. The invention has the advantages of high atom utilization rate, intrinsically sa...

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Problems solved by technology

[0004] However, there is a side reaction in the reaction process of hydrogen peroxide direct oxidation, hydrogen peroxide decomposes to produce oxygen, which forms a mixed gas with propylene, nitrogen and other gases. As the oxygen content in the reaction increases, it will seriously threaten the intrinsic safety of the reaction system. Patent CN201610008220. 8 pointed out that the direct mixing of propylene and oxygen in the gas phase of the direct oxidation method is prone to flash explosion accidents, and the intrinsic safety of the process is insufficient.

At the same time, the gas phase contains organic substances such as propylene. If the method of direct discharge or combustion discharge is adopted, serious pollution will be generated, and resources will be wasted, which will reduce the economic benefits of the process. Handling directly affects process safety and economy

[0005] Patent CN201610008220.8 discloses a treatment device and process for preparing propylene oxide tail gas by direct oxidation of hydrogen peroxide. This method uses an absorbent to absorb propylene in the tail gas, and uses noble metals such as Pt, Pd, and Ru to catalyze oxidation to remove oxygen. However, the method The method has the disadvantages that the catalyst is easily deactivated and the oxygen removal is not complete

[0006] Literature (Jiang Jie. Safety of Propylene Separation Process in Propylene Oxide Production Plant[J]. Journal of Safety and Environment, 2014,14(6):28-31.) reported the explosion of "propylene-oxygen-nitrogen" ternary system limit, and pointed out that the scheme using flash evaporation cannot meet the safety control requirements of gas phase combustion and explosion, and the intrinsic safety of the process is insufficient

[0007] Patent CN201210389707.7 discloses a process for preparing propylene oxide by directly oxidizing propylene with hydrogen peroxide. This process uses a pressurized rectification tower to separate propylene and non-condensable gas. Propylene flows out from the bottom of the pressurized rectification tower, and contains a small amount of organic matter The non-condensable gas is directly discharged into the atmosphere after passing through the gas phase absorption device, and a large amount of VOC is discharged, which is easy to cause environmental pollution

[0008] Patent CN201410578425.0 discloses a method for synthesizing adipic acid from cyclohexanone. The method uses transition metal-modified titanium-silicon molecular sieve as a catalyst to catalyze the oxygen oxidation of cyclohexanone under the conditions of 0.1-2.0MPa and 40-180°C. Preparation of adipic acid, but this method requires azo and peroxide substances as initiators, and the process safety is insufficient

[0009] Patent CN2003118249.6 discloses a method for air oxidation of cyclohexanone to prepare adipic acid. Under the catalysis of porphyrin iron or porphyrin manganese, adipic acid is prepared by air oxidation of cyclohexanone. The catalyst preparation of this process is relatively Complicated, easily deactivated by oxidation, high catalyst cost, and low yield of adipic acid

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