摘要:
The invention relates to a process for isolating H acid and K acid in the form of their monoalkali metal salts from acid aqueous solutions which contain these two acids and alkali metal ions and may contain other aminonaphtholdisulphonic acids, in which process H acid monoalkali metal salts are precipitated at elevated temperatures from solutions which contain not only sodium ions but also potassium ions and then precipitating K acid monoalkali metal salts by cooling down the filtrate obtained after separating off the H acid monoalkali metal salts.
摘要:
A process has been invented for the preparation of a mono-alkali metal salt of 1-amino-8-naphthol-3,6-disulphonic acid comprising reacting 1-naphthylamine-3,6,8-trisulphonic acid and/or a salt thereof and/or a naphthylamine-trisulphonic acid isomer mixture and/or salt thereof with an alkali metal hydroxide solution at elevated pressure and elevated temperature and in the presence of an alcohol or alcoholate, and separating out the mono-alkali metal salt by acidification. The process results in the procurement of higher yields of the desired product and in the formation of less by-products.
摘要:
Solid crystalline tetra-alkali metal salts of chromotropic acid, a process for their isolation and their use for the preparation of pure chromotropic acid or di-alkali metal salts of chromotropic acid.
摘要:
A process has been provided for the preparation of nitro-T-acid by nitration of naphthalene-1,3,6-trisulphonic acid from a nitration mixture which has reacted to the extent of at least 80% which naphthalene-1,3,6-trisulphonic acid or a mixture containing the latter. Nitro-T-acid (and T-acid) is an intermediate for the preparation of H-acid which, in turn, is an intermediate for the preparation of dyestuffs.
摘要:
Improved process for the preparation of 1-naphthylamine-4,6-disulphonic acid wherein the sulphonation of the 1-naphthylamine-6-sulphonic acid is carried out by adding the oleum at a temperature of 10.degree. to 70.degree. C., either to initially introduce sulphuric acid simultaneously with the 1-naphthylamine-6-sulphonic acid or to 1-naphthylamine-6-sulphonic acid, which is dissolved or suspended in sulphuric acid, and by using such a molar ratio of sulphur trioxide to 1-naphthylamine-6-sulphonic acid that 1.2 to 3 mols of sulphur trioxide are present per mol of 1-naphthylamine-6-sulphonic acid. The sulphonation mixture formed in the preparation can be sulphonated in a second sulphonation stage to 1-naphthylamine-2,4,6-trisulphonic acid.
摘要:
A process has been invented for the preparation of a mono-alkali metal of 1-amino-8-naphthol-3,6-disulphonic acid, comprising reacting 1-naphthylamine-3,6,8-trisulphonic acid and/or a salt thereof and/or a naphthylamine trisulphonic acid isomer mixture and/or salt thereof with an alkali metal hydroxide solution in the presence of an alcohol and/or alcoholate and in the presence of a substance which contains at least one oxygen atom bonded to a nitrogen atom, at elevated pressure and elevated temperature, and separating out the mono-alkali metal salt of 1-amino-8-naphthol-3,6-disulphonic acid by acidification. The process results in the procurement of higher yields of the desired product and in the formation of less by-products.
摘要:
The invention relates to a method for producing 3-hydroxy-2-methylbenzoic acid or solutions containing salts of 3-hydroxy-2-methylbenzoic acid, with naphthalene as the starting substance. Said method essentially comprises the following steps: sulfonation, reaction with alkalis at high temperatures and the expedient preparation of the resultant reaction mixture.
摘要:
The invention concerns 4,6-diamino-resorcinol which is prepared in the form of its dihydrochloride by catalytic hydrogenation of 1,3-benzyloxy-4,6-dinitrobenzene on a noble metal contact in a two-phase mixture of dilute aqueous hydrochloric acid and an organic solvent which is not miscible with dilute aqueous hydrochloric acid. This process is carried out at a pressure of between 1 and 200 bar and a temperature of between 0 and 200.degree. C.
摘要:
4,6-diaminoresorcinol can be prepared in a plurality of steps in such a way thata) 1,3-dichlorobenzene is nitrated with a mixed acid of HNO.sub.3, H.sub.2 SO.sub.4 and SO.sub.3 at 0 to 40.degree. C. in anhydrous H.sub.2 SO.sub.4,b) the resulting 1,3-dichloro-4,6/2,4-dinitrobenzene isomeric mixture is first reacted with benzyl alcohol in the presence of a strong base at -15.degree. C. to +15.degree. C. and then at 20.degree. to 40.degree. C. to give the dibenzyloxy compound andc) the 1,3-dibenzyloxy-4,6-dinitrobenzene isomer arising in pure form in b) is converted to the 4,6-diaminoresorcinol by catalytic hydrogenation.
摘要翻译:可以以多个步骤制备4,6-二氨基间苯二酚,使得a)在无水H 2 SO 4中在0至40℃下用HNO 3,H 2 SO 4和SO 3的混合酸硝化1,3-二氯苯,b) 所得的1,3-二氯-4,6 / 2,4-二硝基苯异构体混合物首先在强碱存在下在-15℃至+ 15℃下与苄醇反应,然后在20℃至 40℃,得到二苄氧基化合物,和c)在b)中以纯形式产生的1,3-二苄氧基-4,6-二硝基苯异构体通过催化氢化转化为4,6-二氨基间苯二酚。
摘要:
When 2-naphthylamine-1,5-disulphonic acid is precipitated from the as-sulphonated reaction mixtures by dilution, a purer product is obtained, with a low level of adherent sulphuric acid, if the precipitation by dilution of the reaction mixture is carried out under precisely defined conditions.