Examples of suitable solvents that can be used for this purpose are ketones such as acetone or methyl ethyl ketone, ethers such as tetrahydrofuran or dioxane, amides such as N,N-dimethylformamide, nitriles such as acetonitrile, esters such as ethyl acetate, hydrocarbons such as toluene, and halogenated hydrocarbons such as methylene chloride.