Method for producing dicarboxylic acid

A method for producing dicarboxylic acid, comprising the following steps:

• 1) obtaining an intermediate product system comprising cyclic carboxylic acid ester from a raw material system comprising a cyclic olefin and a lower monocarboxylic acid by an addition reaction in the presence of an addition reaction catalyst;
• and
• 2) carrying out a ring-opening oxidation reaction in the presence of an oxidant and an oxidation catalyst to produce a corresponding dicarboxylic acid product from the intermediate product system;
• wherein the lower monocarboxylic acid is selected from at least one compounds with a chemical formula represented by formula V:
• wherein, R501 is selected from H, C1 to C3 hydrocarbon group or C1 to C3 halogenated hydrocarbon group;
• wherein the addition reaction catalyst in step 1) comprises at least one of a supported inorganic acid catalyst, a cation exchange resin, and a molecular sieve;
• wherein the supported inorganic acid catalyst contains an inorganic acid and a support;
• wherein the inorganic acid is selected from at least one of sodium hydrogen sulfate, sodium hydrogen phosphate, AlCl3 and heteropoly acid, and the support is selected from at least one of silica, diatomite and kaolin;
• and
• wherein the weight percentage of the inorganic acid in the supported inorganic acid ranges from 5% to 25%;
• wherein the cation exchange resin is a sulfonic acid type-macroporous strong acid ion exchange resin whose Hammett index of acid strength is H0<−10, and a H+ exchange capacity of ion exchange resin is greater than 1.0 mmol/L;
• and
• the molecular sieve is selected from at least one of HY, Hβ and HZSM-5 molecular sieves with topological structures of FAU, BEA, and MFI;
• and as measured by NH3 chemisorption determination, the molecular sieve has a weak acid site density ranging from 0.005 mmol/g to 0.35 mmol/g, a medium-strength acid site density ranging from 0.01 mmol/g to 0.5 mmol/g, and a strong acid site density ranging from 0.003 mmol/g to 0.15 mmol/g.