Aromatic sulphonation. Part 92. Sulphonation of the three methylphenols and the six dimethylphenols in concentrated aqueous sulphuric acid; and the lsomerization of some of the resulting sulphonic acids and of m-xylene-2-and o-xylene-3-sulphonic acid

1985 ◽  
pp. 669 ◽  
Author(s):  
Hans J. A. Lambrechts ◽  
Zwaan R. H. Schaasberg-Nienhuis ◽  
Hans Cerfontain
Keyword(s):  
Sulphuric Acid ◽  
Sulphonic Acid

STUDIES IN THE FORMATION OF DDT

1947 ◽  
Vol 25b (6) ◽  
pp. 509-524
Author(s):  
T. A. Eastwood ◽  
D. L. Garmaise ◽  
D. J. Morantz ◽  
C. A. Winkler
Keyword(s):  
Sulphuric Acid ◽  
Acid Concentration ◽  
Side Reaction ◽  
Sulphonic Acid ◽  
Barium Salt ◽  
Molar Amount ◽  
Sulphuric Acid Concentration

In the condensation of chloral and chlorobenzene in sulphuric acid to yield DDT, the yield of DDT is increased and the rate of formation of DDT decreased by (1) decreased sulphuric acid concentration, (2) decreased molar amount of sulphuric acid, and (3) lowered temperatures. Reversible sulphonation of chlorobenzene is the major side reaction; the presence of 4-chlorobenzene-sulphonic acid reduces the extent of this reaction. Increased yields (based on chloral) can be obtained by using excess chlorobenzene. A mechanism is proposed involving 1-(4-chlorophenyl)-2,2,2-trichloroethanol, which has been isolated from the reaction, and 1-(4-chlorophenyl)-2,2,2-tricholorethyl bisulphate, whose barium salt reacts with chlorobenzene in sulphuric acid to give DDT.

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