Method for preparing mononaphthalenesulfonic acid and sodium salt of mononaphthalenesulfonic acid

A technology of sodium naphthalene sulfonate and naphthalene sulfonic acid is applied in the field of preparation of naphthalene sulfonic acid and its sodium salt, which can solve the problems of high purity of 1-naphthol, difficult reaction control, and difficult separation of isomers, and achieves sulfonation The effect of stable reaction, saving solvent consumption and improving yield
CN1958567AInactive Publication Date: 2007-05-09江苏华达化工集团有限公司
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
江苏华达化工集团有限公司
Publication Date
2007-05-09
Estimated Expiration
Not applicable · inactive patent
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Abstract

This invention discloses a method for synthesizing 1-naphthalene sulfonic acid and / or sodium 1-naphthalene sulfonate. The method comprises: (1) dissolving naphthalene in solvent, adding appropriate 1-naphthalene sulfonic acid seed crystals, cooling to 0 minus or plus 5 deg.C, stirring, dropping chlorosulfonic acid within 1-2 h, and keeping at -2-8 deg.C for 1.5-3 h; (2) cooling to 0 minus or plus 2 deg.C, and filtering to obtain the filter cake of 1-naphthalene sulfonic acid; (3) washing the filtrate with water, phase-separating to obtain the solvent and water scrubbing acid (for producing high-performance naphthalene water reducer); (4) neutralizing 1-naphthalene sulfonic acid and the solvent with 5-15% NaOH, keeping at 90 minus or plus 5 deg.C for 10-30 min, phase-separating the neutralization solution to obtain sodium 1-naphthalene sulfonate aqueous solution, cooling to lower than 35 deg.C, crystallizing, filtering to obtain the filter cake of sodium 1-naphthalene sulfonate, and utilizing the filtrate to prepare NaOH solution. The method has such advantages as high sulfonation selectivity, low product isomer content, easy operation and no wastewater.
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Description

technical field

[0001] The invention relates to a preparation method of naphthalenesulfonic acid and its sodium salt, in particular to a preparation method of 1-naphthalenesulfonic acid and 1-naphthalenesulfonic acid sodium salt. Background technique

[0002] 1-Naphthalenesulfonic acid or 1-naphthalenesulfonic acid sodium salt is mainly used to prepare 1-naphthol. Generally, the raw material naphthalene is sulfonated to obtain 1-naphthalenesulfonic acid, and then neutralized and salted out to obtain 1-naphthalene Sulfonic acid sodium salt; 1-naphthalene sulfonic acid sodium salt is obtained by alkali fusion and acidification to 1-naphthol. The existing preparation methods mainly include low-temperature sulfonation method and chlorosulfonic acid sulfonation method according to the sulfonating agent used.

[0003] The low-temperature sulfonation method uses naphthalene as the raw material, uses 98% sulfuric acid as the sulfonating agent, and the sulfonation reaction temperatu...

Claims

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