MUMBAI, India, Oct. 26 -- Intellectual Property India has published a patent application (202621107230 A) filed by Inventys Research Co Pvt Ltd on September 07, 2026, for Telescopic Continuous Process For Selectively Preparing 3,4-Dimethylpyrazole And Its Phosphate Salt Via Controlled Formylation Selectivity.
Inventor includes Dr. Deepak Birewar.
The application for the patent was published on October 23, 2026, under issue no. 43/2026.
Abstract: ABSTRACT TITLE: TELESCOPIC CONTINUOUS PROCESS FOR SELECTIVELY PREPARING 3,4-DIMETHYLPYRAZOLE AND ITS PHOSPHATE SALT VIA CONTROLLED FORMYLATION SELECTIVITY A telescopic continuous process for selectively preparing 3,4-dimethylpyrazole (DMP) involves seven linked steps. First, 2-butanone, a formate ester, and an alkali metal alkoxide base react in a continuous reactor at 20–30°C for 3–5 hours, forming a 2-methyl-3-oxobutanal salt intermediate. This is water-extracted, then continuously metered with a hydrazine compound and acid into a second reactor at 20–60°C under steady-state flow. The mixture is neutralised at 25–35°C, extracted with organic solvent, and distilled at 60–100°C under 50–80 mbar, with solvent recycled. A final vacuum distillation at 60– 180°C under 1–20 mmHg yields DMP of at least 99% purity, with 3-ethylpyrazole content undetectable up to 800 ppm. Compared to the Applicant's own batch process (61.92% yield, 99.2% purity, 2,000 ppm 3-ethylpyrazole), this continuous process delivers 65–71% yield, 87% less hydrazine holdup, ~8× higher throughput, 35% less waste, and stable operation for 110+ hours. Refer
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