Though thiodiglycol has been known for a long timela and has been manufactured on a large scale for making" mustard gas," it has not been extensively studied. It seemed worth while to prepare it and some of its esters in high purity so as to determine their properties. The formate, acetate, benzoate and phthalate are mentioned in a patent2 but not fully characterized. The p-nitro and fi-aminobenzoates have been made. 3