The monomer butyl acrylate is used to produce polymers. Note that methyl, ethyl, propyl, butyl, etc. Accidental aspiration of amyl or butyl nitrites may cause lipoid pneumonia. The solution may add a solvent like d-limonene, petroleum byproducts, glycol ethers, or butyl agents. Many plasticizers are based on butyl esters, e.g., dibutyl phthalate. The four isomers of "butyl acetate" demonstrate these four isomeric configurations. A variety of butyl esters are used as solvents, e.g. butoxyethanol. Soluble polymers are derivable from 3-substituted thiophenes where the 3-substituent is butyl or longer. The first major application of butyl rubber was tire inner tubes. ExxonMobil is the largest producer of butyl rubber. It is one of several isomers of butyl bromide. It undergoes lithiation upon treatment with butyl lithium. With butyl lithium, the product is . Thus reaction of thiophene with butyl lithium gives 2-lithiothiophene, also called 2-thienyllithium. For example, CH3CH2CH2CH2CN is called pentanenitrile or butyl cyanide.