Sumitomo Chemical Company, Limited

Hiromichi Okabe

Kenji Tanimoto

Iwao Dohgane

Yuji Ueda

Hirokazu Hosaka

Norio Kotera

Katsumi Kobayashi

Hiroshi Korenaga

Kiyomi Kishimoto

Fumio Ohi

Kunthiko Tanaka

Highly pure p-phenylenediamine can advantageously be prepared on a commercial scale by separating and removing o-aminoazobenzene produced as a by-product in the step of producing p-aminoazobenzene, from the product mixture before p-aminoazobenzene is reduced in a process for preparing p-phenylenediamine which comprises preparing p-aminoazobenzene from aniline by way of diazoaminobenzene and then reducing p-aminoazobenzene.

Process for preparing and purifying p-phenylenediamine

In a process for producing 8-amino-1-naphthol-3,6-disulfonic acid which comprises subjecting a 1-nitronaphthalene-3,6,8-trisulfonic acid reaction mixture to reduction, subjecting the resulting 1-naphthylamine-3,6,8-trisulfonic acid salt mixture to alkali fusion and subjecting the alkali fusion mixture to precipitation by mixing with an acid to obtain 8-amino-1-naphthol-3,6-disulfonic acid as a partial alkali metal salt, the amount of acids and bases used can be curtailed and the quality of the product can be improved by performing the precipitation by mixing said alkali fusion mixture with said 1-nitronaphthalene-3,6,8-trisulfonic acid reaction mixture, separating the precipitated partial alkali metal salt of 8-amino-1-naphthol-3,6-disulfonic acid by filtration, and using as a starting material for said reduction reaction the resulting filtrate containing 1-nitronaphthalene-3,6,8-trisulfonic acid and/or a salt thereof.

Process for producing 8-amino-1-naphthol-3,6-disulfonic acid

A method for extracting a dihydroperoxide of a dialkylbenzene of the formula, ##STR1## wherein each R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is independently a lower alkyl group, from an aqueous alkali solution of the said dihydroperoxide with at least one organic solvent selected from the group consisting of C.sub.4 -C.sub.10 ketones, C.sub.4 -C.sub.10 ethers and C.sub.4 -C.sub.8 alcohols, which comprises extracting the dihydroperoxide by a countercurrent multi-stage extraction at a temperature between 0.degree. and 85.degree. C with a temperature gradient, the aqueous alkali solution being fed to the lower temperature zone, the organic solvent being fed to the higher temperature zone, and each aqueous alkali solution and organic solvent being fed countercurrently, whereby the dihydroperoxide is obtained in the form of organic solvent solution from the lower temperature zone.

Method for extraction of dihydroperoxide

A process for producing alkylnaphthalenes by alkylating naphthalene with an olefin having 2 to 4 carbon atoms, which comprises (1) introducing the olefin into a solution of crude naphthalene containing thianaphthene as an impurity in a solvent having a boiling point sufficiently different from the boiling point of the naphthalene and alkylnaphthalenes produced that the solvent is separable by distillation in the presence of (i) an aluminum chloride complex consisting of (a) aluminum chloride, (b) hydrogen chloride and (c) an alkylated benzene or naphthalene, or (ii) a solid aluminum chloride which is dissolved into the reaction solution by adding gaseous hydrogen chloride simultaneously with or prior to the introducing of the olefin, (2) aging the reaction solution, and (3) recovering the resulting alkylnaphthalenes, whereby alkylnaphthalenes, containing as monoalkylnaphthalenes a predominant amount of a .beta.-monoalkylnaphthalene, are obtained in a high yield.

Process for producing alkylnaphthalenes

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Ibaraki, Japan

Hiromichi Okabe