Continuous Flow Reactor and Process for Synthesis of Substituted Benzoic Acid

A non-hazardous and continuous oxidation process for preparing a substituted benzoic acid compound of formula (I):

• where:
• R1 is H, F, Cl, Br, I, NO2, amine, or C1-C5 alkyl;
• R2 is H, F, Cl, Br, I, NO2, amine, or C1-C5 alkyl;
• and
• R3 is H, F, Cl, Br, I, NO2, amine, C1-C5 alkyl;
• the process comprising:
• oxidizing, by a continuous process, a compound of formula (A):
• where R1, R2, and R3 are as defined in formula (I), with an oxidizing agent in a continuous process reactor at a temperature from 150° C. to 180° C. and a pressure from 15 bar to 25 bar to obtain the compound of formula (I) with 95% to 100% selectivity.

A continuous process reactor system for synthesizing a substituted benzoic acid compound of formula (I):

• where:
• R1 is H, F, Cl, Br, I, NO2, amine, or C1-C5 alkyl;
• R2 is H, F, Cl, Br, I, NO2, amine, or C1-C5 alkyl;
• and
• R3 is H, F, Cl, Br, I, NO2, amine, C1-C5 alkyl;
• the continuous process reactor system comprising:
• a first reactants feed vessels to pump nitric acid and de-mineralized water to a first acid dilution vessel using a concentrated acid feed pump and a de-mineralized water feed pump;
• a second reactants feed vessel to pump, using reactants feed pumps, a compound of formula (A):
• where R1, R2, and R3 are as defined in formula (I);
• a second acid dilution vessel to pump dilute acid using the feed pumps;
• reactants preheaters to preheat reactants from the first acid dilution vessel and the second reactants feed vessel;
• static mixers to mix the preheated reactants;
• jacketed tubular reactors for reacting the reactants at a temperature from 150° C. to 180° C.;
• reactor crude collection vessels to collect crude product with impurities;
• a continuous filtration system for filtering the product;
• a phase separator to provide organic stream separated from the aqueous stream;
• and
• an aqueous effluent receiver vessel, an organic layer transfer pump, an aqueous recycle pump, an organic receiver vessel, and an organic recycle pump for recycling organic phase, aqueous phase, and nitric acid regenerated from effluent NOX, back to the continuous process reactor system.