Background

Acetic acid lower alcohol esters are a large series of products synthesized by esterification of acetic acid and lower alcohols. They are important fine chemical raw materials and are widely used in solvents, plasticizers, fragrances and organic synthesis intermediates.

The application of tert-butyl acetate in the fields of coatings, solvents and pharmaceutical intermediates has become increasingly widespread, and its demand has also increased significantly. At present, tert-butyl acetate is usually produced by direct conversion method with acetic acid and isobutylene as raw materials. In this method, the purification of tert-butyl acetate needs to be separated by a deacidification tower, a dealcoholization tower, and a refining tower to meet the requirements. Higher, longer process and more equipment.

Application 

1. Tert-butyl acetate can replace a large amount of xylene in the two-component epoxy polyamide coating formulation, and has no effect on the performance of the coating, and can greatly reduce the amount of ozone formed by the coating emissions. Tert-butyl acetate can also be used to replace other solvents with higher ozone formation, including toluene, ketones and other ester solvents.
 
Tert-butyl acetate can also be used as a fast solvent in two-component polyurethane coatings, alkyd coatings and other air-drying coatings, and is very effective in reducing viscosity. At present, the production methods of tert-butyl acetate proposed mainly include acetic anhydride method, acetyl chloride method, acetyl chloride-magnesium method, and methyl tert-butyl ether method. The acetic anhydride method has been industrialized, and other methods have environmental protection and production conditions in the production process. Compared with the acetic anhydride method, it is more difficult.
 
2. Tert-butyl acetate can also be used to prepare gasoline composite antiknock agent
 
Weigh the following components by weight: 50 parts of absolute ethanol, 10 parts of cyclohexanol, 20 parts of toluene, 10 parts of ethyl malonate, 10 parts of polyisobutylene succinimide, 15 parts of tert-butyl acetate, 10 parts methyl tert-butyl ether, 20 parts benzotriazole, 10 parts monostearate, mix the above components naturally for 15-30 minutes; then stir at room temperature and pressure for 15-20 minutes and then pressurize In the reaction kettle, add 80-90 atmospheres, stir for 25-30 minutes and then stand for 24 hours, and discharge the precipitate to obtain the anti-explosive agent.

Preparation and purification 

In the presence of sodium acetate, tert-butanol and acetic anhydride were refluxed and esterified for 10 hours to synthesize tert-butyl acetate.

Synthesis reaction research

The application of tert-butyl acetate in the fields of coatings, solvents and pharmaceutical intermediates has become increasingly widespread, and its demand has also increased significantly. At present, tert-butyl acetate is usually produced by direct conversion method with acetic acid and isobutylene as raw materials. In this method, the purification of tert-butyl acetate needs to be separated by a deacidification tower, a dealcoholization tower, and a refining tower to meet the requirements. Higher, longer process and more equipment.



In this study, the thermodynamics of the synthesis of tert-butyl acetate (TBA) system from acetic acid and isobutylene were calculated and analyzed, and used to guide the selection of process conditions. The reactions are all exothermic, and they are all thermodynamically spontaneous. Lowering the temperature is beneficial to the reaction; the equilibrium constant of the reaction to form TBA is much greater than the value under normal pressure. Therefore, it is necessary to ensure that the isobutene is liquid in the synthesis system of acetic acid and isobutene.
 
Using gas chromatography, through the selection of chromatographic columns, the exploration of analytical conditions, the investigation of qualitative methods, and the determination of component correction factors, a reliable synthesis of tert-butyl acetate and sec-butyl acetate with acetic acid and isobutylene and 1-butene was established. The product analysis method of acetic acid and isobutylene. On the self-built esterification reaction device, three strong acid resins of A10, B, and C are used as catalysts to investigate the reaction temperature, reaction pressure, system space velocity, and raw material acid alkene. Comparing the effects on the reaction, the results show that: each process parameter has basically no effect on the conversion rate of dissolved isobutene, tert-butanol, and isobutene, and the space velocity and pressure have little effect on the conversion rate of acetic acid, TBA selectivity, and oligomer selectivity; acid; The increase in ene ratio can promote the conversion of isobutylene to TBA and effectively inhibit the oligomerization reaction of isobutylene; low temperature is conducive to esterification addition to generate TBA; from the evaluation effect, the A10 catalyst is the best, and its suitable process conditions have been determined: space velocity 4-5 h-1, acid-to-ene ratio 4-5:1, reaction temperature 25℃, and pressure to ensure the liquid phase of the system.