Hengli Group, built from a bankrupt textile mill into a Fortune Global 500 giant, faces US sanctions over alleged Iranian oil purchases.
Its 400,000 bpd Dalian refinery was blacklisted as Trump and Xi prepared to meet, with Washington urging Beijing to pressure Tehran.
Beijing invoked an anti-sanctions law for the first time to defend Hengli.
The impact was immediate: Hengli's Singapore trading arm is shutting, and Wanhua Chemical suspended a benzene agreement.
Despite sanctions, Hengli continues buying oil in yuan and focusing domestically.
Founder Chen Jianhua's journey from a silk trader to an industrial titan is a testament to China's rise.
