Synthesis Of Ammonium Polycarboxylate By Ring Opening Of 1,4 Cyclohexanedione And Its Electrolyte Properties

The miniaturization of military equipment has always been the focus of attention.Compared with solid capacitors and other capacitors,aluminum electrolytic capacitors have lighter mass,which can relatively reduce the load of capacitors.At the same time,branched chain ammonium polycarboxylate aluminum electrolytic capacitors meet the requirements for use in extreme environments.Therefore,branched chain ammonium polycarboxylate is the most promising electrolyte at present.Using 1,4-cyclohexanedione as raw material,Fenton reagent and H₂O₂ as clean oxidant,alkyl radical is generated and reacted with methyl acrylate to realize chain growth of the reaction product.By optimizing the reaction conditions,a long-chain polycarboxylic acid with branched chain is prepared:4-formic acid-6-one-1,11-undecanoic acid,4-keto azelaic acid and 2-methyl-5-keto-octanoic acid.A carbonyl group is added in the product structure,which can form a hydrogen bond with the solvent,Improve the solubility of branched chain carboxylic acids in solvents.The prepared mixed polycarboxylic acid was ammoniated to prepare a mixed branched chain polycarboxylic acid ammonium salt electrolyte,and the electrolyte composition was optimized.The electrochemical performance and low temperature performance of the electrolyte were measured as follows:1.Synthesis of branched chain polycarboxylic acids:the reaction conditions for the preparation of branched chain polycarboxylic acids were discussed and optimized,and the optimal experimental scheme was determined:the molar ratio of Fe²⁺to H₂O₂ in Fenton reagent was 1:1,the molar ratio of Fenton reagent to 1,4-cyclohexanedione was 1:1,the ring opening reaction time was 6 h,and the ring opening reaction temperature was-5℃.The molar ratio of methyl acrylate to 1,4-cyclohexanedione was 1:1.4,the reaction temperature was 5℃,the reaction time was 3 h,and the yield of mixed branched chain polycarboxylic acid was 58.39%;The electrical performance parameters of 10%mixed branched chain polycarboxylate ammonium salt glycol solution were measured as follows:the conductivity at 25℃was 1.28 m S/cm,the water content was 2.26%,the flash voltage was 374 V,the oxidation efficiency was 1.25 V/s,and the p H was between 6 and 7.The electrolyte could meet the normal service conditions of the electrolyte.2.Ammonium salt performance test:the performance of mixed branched chain polycarboxylic acid ammonium salt in electrolyte was tested,and a relatively excellent low-temperature resistant electrolyte e was summarized.Its electrochemical performance was measured at 25℃,with a conductivity of 3.17 m S/cm and a flash voltage of 413 V.while the electrolyte had a conductivity of 1.15 m S/cm,a flash voltage of 447 V and a p H value of 6.13 at-40℃.Under the low temperature environment,the electrolyte remains liquid,can work normally,and has good low temperature performance and electrochemical performance.