Some hasty renewal for hydrocarbon (7)
I believe the answer is:
styrene
'for hydrocarbon' is the definition.
(I've seen this before)
'some hasty renewal' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'STYRENE' is hidden within 'hasty renewal'.
(Other definitions for styrene that I've seen before include "Petroleum by-product used to make plastics" , "hydrocarbon" , "Chemical" , "Component of plastic" .)