Study On Comprehensive Utilization Of Residue Generated In The Process Of Producing ?-Acetyl-?-butyrolactone

?-Acetyl-?-butyrolactone is an important organic chemical raw material and important intermediate for the synthesis of vitamin B₁,antianginal drugs and other drugs.At present,the process for producing?-acetyl-?-butyrolactone is generally used in the industry by using ethyl acetate and?-butyrolactone as raw materials and sodium metal as catalyst.However,some side reactions in the production process can lead to a certain amount of residue after the distillation of crude products.The residue is classified as hazardous waste by the state,the accumulation of residues will not only pollute the environment,but also may have some potential safety hazards.At present,there are still the following problems in the treatment and utilization of the residue:the composition of the residue is unknown,the reaction mechanism is unclear,entire process operationis intricate,energy-intensive,and inefficient,the newly generated residue is not treated.In view of the above problems in the process of residue utilization,the following researchs are carried out.?1?Determination of the composition of the residue and its formation mechanism.The components and contents of residues were determined by GC-MS.According to the analysis of molecular ion peak of each component and its fragment ion,the molecular structure formula of each component was determined and its formation mechanism was discussed.The results showed that residue was mainly composed of 9 substances,accounting for 97.56%of the residue,there are 3 components with the content of more than 10%.The formation mechanism of each substance is determined as follows:in the process of producing?-acetyl-?-butyrolactone,aldol condensation reaction or claisen condensation reaction occur between the raw material and the raw material,the raw material and the product,and the product and the product,and then dehydrated or decarboxylated.?2?Study about synthesis of cyclopropyl methyl ketone and dicyclopropyl ketone from residue.Firstly,according to the composition structure of the residue and the theoretical knowledge of organic synthesis,a research scheme for the synthesis of cyclopropyl methyl ketone and dicyclopropyl ketone from the residue was put forward,and the reaction mechanism of the research scheme was analyzed.Meanwhile,according to the reaction mechanism,the production process was improved.The effects of reactant ratio,reactant concentration,time and temperature on the reaction results were studied.At last,the optimum technology was scaled up and tested.The results showed that it is feasible to generate cyclopropyl methyl ketone and dicyclopropyl ketone from the residue after the two reaction stages of adding acid and alkali.The reaction mechanism of this process is as follows:residue decomposition under acidic conditions?hydrolysis?decarboxylation?chlorination?alkaline cyclization.The alkali treatment of intermediate products were changed from separate treatment to combined treatment,which reduces unit operation,reduces energy consumption and improves production efficiency.The yield of the pilot scale amplification is basically consistent with the laboratory,which verifies the feasibility of the process.?3?Study on reutilization of residual secondary residue after purification of cyclopropylmethyl ketone and bicyclopropyl ketone.Firstly,the toxicity of the secondary residue is determined according to the chemical toxicity identification technical specification.Then,the secondary residue is mixed with asphalt,and the modifier is added to prepare the asphalt-based anticorrosive coating.The coating is coated,the anticorrosive performance of coating film is measured,and the influence of different proportions of residue on its properties is discussed.The results showed that the secondary residue is a harmless chemical.When the mixing ratio of the secondary residue does not exceed 10%,the performance of the prepared asphalt-based anticorrosive coating film meets the relevant national standards and has good anti-corrosion effect.In this paper,by determining the composition and content of the residue,the research scheme of synthesis of cyclopropyl methyl ketone and dicyclopropyl ketone from the residue is put forward and the reaction mechanism is studied,simplifies the process of residue treatment,reduces energy consumption,improves production efficiency and reuses the newly produced secondary residues.This study not only solve the pollution and safety hazard of residues generated in the production process of?-acetyl-butyrolactone,but also produce high value drug intermediates dicyclopropyl ketone and cyclopropyl methyl ketone,which has considerable economic benefits,and provided the basis for its industrialization production.