121364-05-4Relevant academic research and scientific papers
Sulfonation and sulfation on reaction of 1,2-dihydroxybenzene and its methyl ethers in concentrated aqueous sulfuric acid
Cerfontain, Hans,Coenjaarts, Norbert J.,Koeberg-Telder, Ankie
, p. 325 - 330 (1988)
The homogeneous sulfonation of 1,2-dihydroxybenzene (1), its monomethyl (2) and dimethyl ether (3) in concentrated aqueous sulfuric acid at 25 deg C has been studied and isomer distributions, as well as rate coefficients for the sulfonation of 1-3 and their monosulfonic acids, have been determined.In 73.5-87.5percent H2SO4, 1 yields the 3- and 4-sulfonic acids in a ratio of 25:75, 2 yields the 4-, 5- and 6-sulfonic acids in a ratio of 46:36:18 in 73.5percent H2SO4 and 50:39:11 in 87.5percent H2SO4, whereas 3 yields only the 4-sulfonic acid.The remarkable absence of the 3-sulfonic acid (87.5percent H2SO4, the 4-sulfonic acid of 1 and the 5-sulfonic acid of 2 are present in part in the form of their hydrogen sulfate.In that acid region, the 3- and 4-sulfonic acids of 1 both yield the 3,5-disulfonic acid, the 4- and 6-sulfonic acids of 2 both yield the 4,6-disulfonic acid and the 4-sulfonic acid of 3 mainly yields the 4,6- together with some 4,5-disulfonic acid.
Reactions of the dihydroxybenzenes and their methyl ethers with sulfur trioxide. The effect of initial sulfation on the sulfonation product distribution
Cerfontain, Hans,Coenjaarts, Norbert J.,Koeberg-Telder, Ankie
, p. 7 - 13 (2007/10/02)
The sulfation and sulfonation resulting from the reaction of the dihydroxybenzenes and their mono- and dimethyl ethers with SO3 in nitromethane have been studied, and their product distributions are reported.As to the non-hydroxy-substituent-containing substrates, 1,2-dimethoxybenzene (3) yields the 4-sulfonic acid (3-4-S) which, upon further sulfonation, yields a 1:4 mixture of the 3,5- and 4,5-S2.The 1,3- (6) and 1,4-isomer (9) yield initially the 4- and 2-S, respectively, and subsequently exclusively 6-4,6- and 9-2,5-S2, respectively.With the substrates containing one hydroxy substituent, the sulfonation isomer distribution is dependent on the SO3 to substrate ratio if the OH and OMe substituents are in ortho or para orientation, due to increasing sulfonation of the corresponding methoxyphenyl hydrogen sulfate.Thus, 2-methoxy- (2) and 4-methoxyphenol (8) with one equiv of SO3 at 0 deg C yield a 3:1 mixture of 2-4-S and 2-5-S and a 9:1 mixture of 8-2-S and 8-3-S, respectively, but, with >/= 4 equiv of SO3, the former reactant yields only 2-5-S and the latter only 8-3-S. 3-Methoxyphenol (5) yields initially a 1:1 mixture of the 4- and 6-sulfonic acid.Further sulfonation yields only 5-O,4,6-S3 which slowly cyclizes to the 1,3,2,4-benzodioxadithiin 2,2,4,4-tetraoxide derivative 11.As to the dihydroxy-containing substrates, 1,2-dihydroxybenzene (1) with 1 equiv of SO3 first yields the hydrogen sulfate 1-O-S which rearranges to 1-4-S; on using an excess of SO3, the eventual product is 1-O(2),4-S2.Similarly, the 1,4-isomer (7) with 1 equiv of SO3 yields initially 7-O-S which isomerizes to 7-2-S.With 6 equiv of SO3, initially 7-O,O-S2 is formed and subsequently its 2-sulfonic acid, which eventually cyclizes slowly to the 1,3,2,4-benzodioxadithiin 2,2,4,4-tetraoxide derivative 12.The 1,3-isomer 4 with 1 equiv of SO3 yields the 4-sulfonic acid.With 4 equiv of SO3, initially 4-O,O-S2 is formed and subsequently 4-4,O,O-S3, which is converted into both 4-O,O,4,6-S4 and the cyclization product 10.Eventually, small amounts of 4-O,2,4,6-S4 and 14-2,6-S2 are formed by transsulfonation.
