What are the key production routes and purity requirements for m-cresol in China?

What are the key production routes and purity requirements for m-cresol in China?
m-Cresol is produced via two main routes: extraction from coal-tar cresol fractions and chemical synthesis. Extraction is simpler but yields product with high impurities, unsuitable for food, pharmaceutical and high-end fragrance applications unless costly purification is applied. Synthetic routes include toluene chlorination-hydrolysis, cymene (isopropyltoluene) oxidation, and diazotization of m-toluidine. The cymene route, using toluene and propylene with AlCl3 catalyst at 85-115°C, offers higher selectivity for the meta isomer. China's overall technology lags overseas leaders in catalyst selection and process control. Commercial grades are typically 95% or 98% purity, with 98% commanding a premium for downstream uses like vitamin E intermediates (TMHQ), pyrethroid pesticides, thymol and menthol. Domestic producers include Haihua, Dongying Haiyuan and Anhui Shilian, while coal-tar-based separation remains a supplementary source.