- H acid synthesis method
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The invention provides a synthesis method of an H acid. By taking 1,8-naphthalic anhydride as a raw material, the H acid is obtained by sulfonation, ammoniation, Hofmann degradation and hydrolysis. The method is mild in process condition, and does not have harsh production conditions such as ultralow temperature, high temperature and high pressure; the number of production steps is small, and thenumber of equipment is small; therefore, the synthesis method is suitable for large-scale industrial production.
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Paragraph 0025; 0032-0033; 0042-0043; 0051-0052
(2018/03/24)
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- Synthesis, characterization and RP-HPLC method development and validation for simultaneous determination of Koch acid and H acid
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1-amino-8-naphthol-3,6-disulfonic acid (H acid) is an important intermediate used for the synthesizing some dyestuffs and pharmaceuticals. The synthesis of H acid was followed by sulfonation, nitration, reduction and alkali fusion. The total yield was increased to 35% with 99% purity. This study focuses on cheap synthesis of H acid on an industrial scale. The composition and percentage of these compounds were characterized by making reactive dyes and chromatographic analysis, i.e. UV/Visible, IR and HPLC. The RP-HPLC method was developed; in the analysis of Koch acid (1-amino-naphthalene-3,6,8-trisulfonic acid) and H acid. The single HPLC method is useful, both, in the chemical intermediate (Koch acid) and for the final product (H acid).
- Bokhari, Syed Ahmad Raza,Khan, Rana Rashad Mahmood,Tahir, Muhammad Saqlain,Tahir, Naveed,Syed, Quratulain,Adnan, Ahmad
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p. 469 - 478
(2016/08/31)
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- Method for preparing energy-efficient H-acid
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The invention discloses a method for preparing energy-efficient H-acid. The method comprises the steps of conducting sulfonation on liquid naphthalene to obtain a sulfonated substance, conducting nitration on the sulfonated substance to obtain a nitrated substance, conducting denitration on the nitrated substance to obtain a denitrated substance, conducting extraction on the denitrated substance to obtain dilute sulphuric acid and an extraction mixture, conducting reextraction on the extraction mixture to obtain nitro T-acid solution, conducting reduction on the nitro T-acid solution to obtain amino T-acid solution, conducting concentration on the amino T-acid solution and caustic soda liquid to obtain concentrated amino T-acid solution and caustic soda, conducting alkali fusion and dilution on the concentrated amino T-acid solution and caustic soda to obtain a diluted alkali fusion substance, conducting separation and filtration on the diluted alkali fusion substance to obtain H-acid filter cakes, and conducting drying on the H-acid filter cakes to obtain H-acid. By the adoption of the method, continuous production of H-acid can be achieved, and economic cost is low.
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Paragraph 0064; 0065; 0066; 0067
(2016/10/08)
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- Polyazo dyes containing a plurality of hydroxy sulfonyl groups
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Polyazo dyes of the formula I STR1 where one of the two radicals X1 and X2 is hydroxyl and the other is amino, p and q are each independently of the other 0 or 1, D1 and D2 are each independently of the other a radical of the formula STR2 and B is a bridge member are prepared using novel sulfonamide intermediates and are useful as dyes for dyeing natural or synthetic substrates.
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- Monoazo compounds having vinylsulfone type fiber reactive group and method for dyeing or printing fiber materials using the same
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A monoazo compound of the following formula, STR1 wherein D is phenylene or naphthylene; X is halogeno, pyridinio or STR2 B is --OR3, --SR4, STR3 in which R3, R4, R5 and R6 are each hydrogen, alkyl, phenyl, naphthyl or benzyl, r is 0 or 1, and E is O, SO, SO2, CH2 or NR8, in which R8 is hydrogen or C1 -C4 alkyl; R, R1, R2 and R7 are each hydrogen or alkyl; A1, A2 and A3 are each phenylene, naphthylene or alkylene; Z1, Z2 and Z3 are each --SO2 CH=CH2 or --SO2 CH2 CH2 Y, in which Y is a splittable group; and p is 0 or 1; which compound is useful for dyeing or printing fiber materials to obtain a product dyed or printed in a color superior in various fastness properties with superior build-up property.
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- Reactive dyes having an allylsulfonyl or propargylesulfonyl group
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Reactive dyes useful for dyeing or printing hydroxyl- or nitrogen-containing substrates have the formula STR1 where Rg is a radical of the formula STR2 Ar is the radical of a benzene or naphthalene ring, Z1 and Z2 are each hydrogen, substituted or unsubstituted C1 -C4 -alkyl, substituted or unsubstituted phenyl, C1 -C4 -alkoxy, carboxyl, C1 -C4 -alkoxycarbonyl, cyano, halogen or hydroxysulfonyl, Z3, Z4 and Z5 are each hydrogen, substituted or unsubstituted C1 -C4 -alkyl or substituted or unsubstituted phenyl, U is a group which is detachable under alkaline reaction conditions, X is in case a) the radical of a chromophore or in case b) the radical of a coupling component to which may additionally be attached, via an azo bridge, the radical of a diazo component and which may have additional reactive groups, and L is in case a) a bridge member or in case b) an azo bridge.
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- Copper complexes of sulpho groups containing disazo dyestuffs
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The new disazo dyestuffs of the formula (I) STR1 in which the substituents and indices have the meaning given in the description, and salts thereof are outstandingly suitable for dyeing cellulose-containing materials and leather in blue shades having good wet- and light-fastnesses.
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- Aromatic azo sulfonylnitrene compounds
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Compounds of the structure SPC1 Wherein R and R1 are the same or different and are selected from the group consisting of hydrogen, halogen, and alkyl from one to four carbon atoms, inclusive, and R2 is a substance which inhibits thrombogenic or clotting activity of a material and is that portion of a substituted aromatic which couples with a diazonium salt.
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