Abstract:
Condensation of naphthalenesulphonic acids with aldehydes or with substances yielding aldehydes in an acid medium, to give products containing two or three napthalenesulphonic acid groups linked by aldehyde residues, is effected above 100 DEG C. at increased hydrostatic pressure. Preferred reactants are the 2-sulphonic acid and formaldehyde (or paraformaldehyde, hexamethylenetetramine or trioxymethylene) but the 1-sulphonic acid, the 1,6- ,2,6- and 2,7-disulphonic acids, acetaldehyde, paraldehyde, propionaldehyde, butyraldehyde, glyoxal and furfural are also mentioned.
Abstract:
b -Chloroethane sulphochloride is prepared by reacting ethane, SO2 and Cl2 under the action of high-energy radiation and/or in the presence of substances forming free radicals and in the presence of an inert solvent, and then fractionally distilling the reaction mixture, at least 1 mole of SO2 and at least 2 moles of Cl2 being used for each mole of ethane. The solvent may be the reaction mixture obtained in a previous reaction. Hydrogen chloride gas may be passed in at the beginning of the reaction. In examples, CHCl2-CH3, CCl3-CH3, CHCl2-CH2Cl, CCl3-CH2Cl and C2H5SO2Cl are obtained as by-products. b -Chloroethane sulphochloride may be reacted with methanolic caustic soda solution to give methyl vinylsulphonate.