Ten volumes of the purest coal-tar benzene were shaken for four hours with one volume of sulphuric acid, the acid layer was removed and neutralized with lead carbonate, and the lead thiophen sulphonate obtained was distilled with an equivalent quantity of ammonium chloride.
Perkin; the method being to sulphonate anthraquinone, and then to convert the sulphonic acid into its sodium salt and fuse this with caustic soda.
Lunge, Berichte, 1877, 10, p. 12 75); by fusing sodium benzene sulphonate with sodium formate: C6H5S03Na+-HC02Na=C6HS000Na+ NaHS0 3; by heating calcium phthalate with calcium hydroxide to 330 0 -350° C.; by heating benzotrichloride with water in a sealed tube, and from the hippuric acid which is found in the urine of the herbivorae.
Bokorny, moreover, it appears that such filaments will yield :starch from formaldehyde when they are supplied with sodium -oxymethyl sulphonate, a salt which readily decomposes into formaldehyde and hydrogen sodium sulphite, an observation which has been taken to mean that formaldehyde is always a stage in the synthesis of starch.
A-Naphthol may be prepared by fusing sodium-a-naphthalene sulphonate with caustic soda; by heating a-naphthylamine sulphate with water to 200° C. (English Patent 14301 (1892)); and by heating phenyl isocrotonic acid (R.