How is isoprene extracted from C5 fractions, and what drives its supply in China?

How is isoprene extracted from C5 fractions, and what drives its supply in China?
Isoprene is predominantly recovered from steam-cracked C5 fractions, a byproduct of naphtha cracking for ethylene, typically accounting for about 10% of ethylene output. China's C5 separation technology, pioneered by Sinopec Shanghai Petrochemical since 1982, has matured into full-component separation processes that yield high-purity isoprene alongside piperylene and cyclopentadiene. Domestic capacity reached roughly 380,000 t/y across 15 producers, with Sinopec affiliates Yanshan and Shanghai being the largest. Demand sits near 250,000 t/y, keeping the market roughly balanced but intensely competitive. Historically, China burned C5 as fuel before mastering separation, but now the value chain supports synthetic rubber, SIS, and fine chemicals. Supply growth hinges on ethylene cracker runs and feedstock composition, making isoprene availability tightly linked to broader petrochemical operating rates.