It may be synthetically prepared by fusing potassium benzene sulphonate with caustic alkalis (A.
A thiophenol, C 6 H 5 SH, is known, and is prepared by the action of phosphorus pentasulphide on phenol, or by distilling a mixture of sodium benzene sulphonate and potassium sulphydrate.
The residue crystallizes slowly, and the crystalline product is almost wholly d-benzyl-allyl-phenyl-ammonium-d-sulphonate, the corresponding /-compound remaining as a syrupy residue.
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.
0-Naphthol, C 1 oH 7 OH, prepared by fusing sodium 0-naphthalene sulphonate with caustic soda, crystallizes in plates which melt at 122° C. With ferric chloride it gives a green colouration, and after a time a white flocculent precipitate of a dinaphthol.