Solvent one takes to Tyneside (7)
I believe the answer is:
acetone
'solvent' is the definition.
(acetone is a kind of solvent)
'one takes to tyneside' is the wordplay.
'one' becomes 'ace' (synonyms).
'takes' says to put letters next to each other.
'tyneside' becomes 'ne' (region in North East of England).
'ace'+'to'+'ne'='ACETONE'
(Other definitions for acetone that I've seen before include "it dissolves" , "Industrial solvent" , "Colourless solvent" , "Paint thinner" , "Remover of nail polish" .)