sulphonic acid
A class of organic compounds composed of sulfo groups and hydrocarbon groups (including aryl groups). The general formula is shown in the left figure, in which R is hydrocarbyl. Sulfonic acid is mostly a synthetic product, and only a small amount of sulfonic acid exists in nature, such as β-aminoethanesulfonate n H2 ch 2 so 3h. Sulfonic acid group is a strong water-soluble strong acid group, and sulfonic acid is a water-soluble strong acid compound. The sulfonic acid groups in aromatic sulfonic acid molecules can be replaced by hydroxyl groups and cyano groups, which are intermediates for the preparation of phenol and nitrile. Sulfonic acid can be prepared by sulfonation of aromatic hydrocarbon or oxidation of mercaptan. Methanesulfonic acid can be used as a catalyst for esterification, hydrolysis and alkylation. The sodium salt of long-chain sulfonic acid, such as n-C 1 1H23-CH2, is a hard water resistant detergent. Sulfonic groups in many dye molecules can make colored compounds soluble in water. Sodium dodecyl benzene sulfonate can be used as detergent. Sulfonyl chloride can be prepared from sulfonic acid, which is very useful in organic synthesis. H part of sulfonic acid molecule can be substituted by halogen atom, amino group, etc. For example, sulfonyl chloride is a commonly used intermediate in organic synthesis and analytical chemistry. Sulfanilamide is an anti-inflammatory drug. Saccharin sodium is also a sulfanilamide.