isopropyl alcohol

Isopropyl Alcohol, aka "rubbing alcohol", is a fine and useful solvent, and eminently flammable, so I'm thinking it might not be allowed on a flight with me, even in checked baggage. I know in the past traditional rubbing alcohol formulations (70% isopropyl alcohol, 30% water) *have* been allowed on planes, even as carry on items, but I have a 250mLs of 99.8% pure in a pump action bottle...

Is it readily bought in China instead?

It does in any case exist in Chinese:

异丙醇
yìbǐngchún

Where might one purchase the stuff?

It does in any case exist in Chinese:

异丙醇
yìbǐngchún

Where might one purchase the stuff?

Probably any pharmacy. Also available for delivery on JD.com

https://search.jd.com/Search?keyword=异丙醇&enc=utf-8&wq=异丙醇&pvid=8vqprtxi.17tw73

Turns out "rubbing alcohol" is a generic term for both ethanol and isopropyl alcohol solutions, and that the ethanol version or at least the "rubbing alcohol" version - 酒精 - is likely available at any pharmacy.

The internet also tells me the IPA (isopropyl alcohol) and ethanol versions are about the same at disinfecting and sterilising, but that IPA likely will be less harmful to the plastics in, say, computer hardware. That's what I want it for, de-greasing and antibacterialising my phone. Maybe computer stores have the IPA?

I've gotten it from pharmacies.  It may take a little looking around and some explanation that you do NOT want ethanol, but any big pharmacy should be able to help you.