Application of alkylbenzoic acid intermediates: Alkylbenzoic acid is a very important organic chemical intermediate, with wide use in preservatives, protection agents, pesticides, pharmaceuticals, organic dyes, photographic materials, disinfectant, fluorine-containing pharmaceutical and other fields.
Alkylbenzoic acid is a raw material of synthesizing alkylcyclohexyl carboxylic acid, alky carboxylate, fluorinated benzoic acid and other organic chemical products. Besides, it is popular in ester liquid crystals.
Recently, studies on alkylbenzoic acid intermediates have been booming. A series of alkylbenzoic acid products have been developed. They mainly are: Methyl benzoate, ethyl benzoate, isopropyl benzoate, p-tert-butyl benzoic acid,etc. P-tert-butyl benzoic acid (PTBBA), also named para-tert-butyl benzoic acid, 4-tert-butylbenzoate, 4-(tert-butyl) benzoic acid, etc, is colorless needle crystalline or crystal powder. It is a very important intermediate for organic synthesis and the main usages are: modifier of alkyd resin; additive of cutting oil and lubricating oil; nucleating agent of polypropylene; food preservatives; Polyester polymerization moderator; additives of car deodorizer, outer membrane of oral drug, alloy preservatives, lubricity additives, polypropylene nucleating agent, heat stabilizer for PVC, metal processing cutting fluid, antioxidant, alkyd resin improving agent, flux, dyes and novel sunscreen agent; it is also used for production of methyl p-tert-butyl benzoate, which is widely used in chemical synthesis, cosmetics, flavors and fragrances and other industries. Its barium, sodium, zinc salts could be used as stabilizer of polyethylene.
Synthesis methods of P-tert-butyl benzoic acid.
(1)Solvent-free liquid phase oxidation method
(2)Nitric acid oxidation method
(3)Acetate solvent catalytic oxidation method
(4)Microwave radiation method
(5)Potassium permanganate oxidation method
The solvent-free liquid phase oxidation method
This method takes p-tert-butyl toluene (PTBT) as the raw material, Cobalt acetate as catalyst. Using 40% acetaldehyde as initiator agent will shorten the induction period. The reaction is at a temperature of 170 ℃. After 100 min, the p-tert-butyl benzoic acid productivity is 50%, with selectivity of 98%. It is ensured that the reaction has turned to be first degree at 170 ℃, the oxidation reaction rate just have connect with the concentration of PTBT. The procedures are: the oxidation reaction device is 2L autoclave, with speed adjustable stirrer. The autoclave bottom is an air distribution. The top is connected with condenser. PTBT after condensation and yielded water pour into the separation tank. The upper layer PTBT go back to the autoclave and underlayer water is taken out. Exhaust gas exit is connected with oxygen analyzer, to test the oxygen consumption in the reaction and judge the progress of the reaction. Sampling in a certain period to test p-tert-butyl toluene content in the reaction solution and analyzing the relationship of yielded p-tert-butyl benzoic acid quantity with reaction.