Mitsubishi Gas Chemical Company, Inc.

Mitsubishi Gas Chemical, Inc.

Makoto Takagawa

Norio Fushimi

Kenji Inamasa

Ryusuke Shigematsu

Kenichi Nakamura

Ko Kedo

Akio Hashimoto

Takehiko Takahashi

Ken Yamagishi

Shinji Ozawa

Takayo Sasaki

Toshio Hidaka

Kinji Kato

Kumiko Watabe

Kazuo Takada

Toshihiro Hashimoto

Tamotsu Ueno

Kazuo Nagagata

Nobuo Isogai

Takashi Kojima

Takayasu Fujimori

Mikio Yoneoka

Minoru Osugi

Tadasi Nakamura

Tomiyoshi Furuta

Masayoshi Hayashi

Kinya Tsuji

Youichi Kyuuko

Takeshi Koshikawa

Kuniaki Ageishi

Jyun Yoshihara

Yoichi Kyuko

Kenji Dnamasa

5-Tolyl-pent-2-ene is cyclized in liquid phase in the present of an aliphatic hydrocarbon to produce the corresponding dimethyltetralin. The use of the aliphatic hydrocarbon effectively prevents a side reaction such as dimerization of 5-tolyl-pent-2-ene to provide dimethyltetralin in a high yield. Also, 5-tolyl-pent-2-ene is cyclized in liquid phase or vapor phase in the presence of a catalyst comprising a carrier supporting sulfate ions to produce the corresponding dimethyltetralin. The catalyst supporting sulfate ions shows a high catalytic activity event at low temperatures. Therefore, the cyclization of 5-tolyl-pent-2-ene is conducted in a wide temperature range from low temperatures to high temperatures.

Process for producing dimethyltetralin

Highly pure, less colored aromatic polycarboxylic acids are produced from crude aromatic polycarboxylic acids by simple procedures at low production costs. The crude aromatic polycarboxylic acid is mixed with aliphatic amine or alicyclic amine in the presence of a solvent to precipitate crystals of amine salt of aromatic polycarboxylic acid. The crystals are dissolved in water and decomposed, thereby obtaining the highly pure aromatic polycarboxylic acids.

Process for producing highly pure aromatic polycarboxylic acid

There are disclosed an industrially advantageous process for efficiently producing highly pure 2,6-dimethylnaphthalene (DMN) in high yield from a mixture of DMN by carrying out in turn, the steps of isomerizing a mixture of DMN in the presence of a catalyst; crystallizing the isomerization reaction product in the presence of a solvent (e.g. an aliphatic or alicyclic saturated hydrocarbon) to precipitate 2,6-DMN crystal; isolating and recovering the 2,6-DMN thus precipitated; and distilling the mother liquor formed after the isolation of the crystal to obtain DMN fraction by removing the components having a higher boiling point than DMN and the components having a lower boiling point than DMN, while at least part of the DMN fraction is returned to the isomerization step and circulated through the process; a process for producing a 2,6-naphthalenedicarboxylic acid by subjecting the 2,6-DMN obtained by the above process to liquid-phase oxidation; and a process for producing 2,6-naphthalenedicarboxylic acid ester by esterifying 2,6-naphthalenedicarboxylic acid thus produced.

Process for producing highly pure 2,6-dimethylnaphthalene

A process for producing highly pure 2,6-dimethylnaphthalene in a high yield from a mixture of dimethylnaphthalene isomers in the presence of a solvent, such as an aliphatic or alicyclic saturated hydrocarbon. Highly pure 2,6-dimethylnaphthalene can be produced steadily for a long time by filtering the 2,6-dimethylnaphthalene crystal precipitated by the crystallizing by using a filtration apparatus, such as a rotary vacuum filter, peeling-off the filtered cake from a filter cloth and cleaning the filter cloth with a solvent, at a temperature not lower than a filtration temperature.

Process for producing 2,6-dimethylnaphthalene

Provided is a process for producing benzoyl chlorides which comprises reacting an aromatic aldehyde with chlorine in liquid phase in the presence of inert gas, whereby the generation of benzal chlorides by products whose separation is difficult can be suppressed.

Process for producing benzoyl chlorides

A process for producing a high-purity naphthalenedicarboxylic acid having an improved hue or an excellent hue from a crude naphthalenedicarboxylic acid obtained by the oxidation of dialkyl naphthalene, industrially advantageously at high yields, which comprises dissolving a crude naphthalenedicarboxylic acid obtained by the oxidation of dialkyl naphthalene in an aqueous solution containing an aliphatic amine, an alicyclic amine or acetonitrile, removing heavy metal components contained as impurities until the content of the heavy metal components based on the crude naphthalenedicarboxylic acid is 100 ppm or less, and heating the aqueous solution containing a naphthalenedicarboxylic acid amine salt to distill off the amine.

Process for the production of high-purity naphthalenedicarboxylic acid

A process for the production of a pyridinecarboxylic acid by the air-oxidation of an alkylpyridine in a liquid phase, in which the conversion of the alkylpyridine is high, the yield of the pyridinecarboxylic acid is therefore high, the content of impurities in the product is decreased, and unreacted raw material and an oxidation intermediate can be recycled without the adverse effect of accumulation of the catalyst and bromine component, the process comprising oxidizing an alkylpyridine with an oxygen-containing gas in a solvent in the presence of a catalyst formed of a heavy metal salt and a bromine compound, the solvent being a lower aliphatic monocarboxylic acid having a water content of 2 to 15% by weight, or the process comprising the step of catalytically hydrogenating an oxidation reaction mixture or an isolated pyridinecarboxylic acid in the presence of a catalyst of a metal belonging to the group VIII of the periodic table.

Process for the production of pyridinecarboxylic acids

A process for producing a monoalkenyl aromatic hydrocarbon which comprises alkenylating a side chain of an aromatic hydrocarbon compound having at least one hydrogen atom at the .alpha.-position of a side chain (such as o-xylene) with a conjugated diene having 4 or 5 carbon atoms in the presence of a catalyst slurry prepared by adding an aromatic hydrocarbon compound to a catalyst comprising a alkali metal and an alkali metal compound. In the aforementioned process, it is particularly effective that the catalyst slurry is prepared by adding the aromatic hydrocarbon compound after the aromatic hydrocarbon compound has been deoxygenated and dehydrated by distillation, and the catalyst slurry thus prepared is supplied to the reaction system. According to the aforementioned process, an industrially useful monoalkenyl aromatic hydrocarbon compound, such as a monoalkenylbenzene, can be produced at a high selectivity, in a high yield, and with enhanced safety and stability for a long time.

Process for producing a monoalkenyl aromatic hydrocarbon compound

Provided is a process for producing alkylbenzoyl chloride which comprises reacting alkylbenzaldehyde with chlorine at a temperature of -10.degree. to 80.degree. C. under a pressure of 5 kg/cm.sup.2 or below in a liquid phase, whereby alkylbenzoyl chloride can be produced in a high yield and at a low price.

Process for producing alkylbenzoyl chloride

Their is disclosed a process for producing a monoalkenyl aromatic hydrocarbon compound (e.g. 5-(o-tolyl)-2-pentene) which comprises the steps of alkenylating a side chain of an aromatic hydrocarbon compound having at lease one hydrogen atom bonded to .alpha.-position of the side chain (e.g. alkylbenzene) by the use of a conjugated diene having 4 to 5 carbon atoms (e.g. 1-3 butadiene) in the presence an alkali metal-based catalyst supported on a carrier; removing at least part of the catalyst from the resultant reaction product by separating the same; inactivating and optionally removing the catalyst contained in the reaction product; and thereafter distilling the reaction produce in liquid form to separate and recover the objective monoalkenyl aromatic hydrocarbon compound. By virtue of using the above specific method, the process can prevent the change in quality and properly of the objective product even during atmospheric distillation, produce the objective product with high purity in high recovery race and operate a distillation column during a long stable period of time.

Process for producing monoalkenyl aromatic hydrocarbon compound

There is disclosed a method for isomerizing dimethylnaphthalene (DMN) in liquid phase under atmospheric pressure by using a catalyst comprising hydrogen-form mordenite which has a molar ratio of silica to alumina (SiO.sub.2 /Al.sub.2 O.sub.3 ratio) of at least 100 and is molded by incorporating alumina as the molding aid therein. According to the above method, the objective 2,6-DMN minimized in the contents of impurities can stably be produced in high selectivity and high yield under mild reaction conditions for a long period of time, while side reactions and deterioration of the catalyst are suppressed to a minimum.

Method for isomerizing dimethylnaphthalene

A method for isomerizing dimethylnaphthalene (DMN) in the gaseous phase in the presence of a solvent comprising an aromatic hydrocarbon having a boiling point of at most 150.degree. C., e.g., benzene, under atmospheric pressure by using a catalyst comprising a hydrogen-form of mordenite. According to the method, the objective 2,6-DMN can be produced with a minimal content of impurities and the 2,6-DMN can be stably produced in high selectivity and high yield under mild reaction conditions for a long period of time, while suppressing side reactions.

A process for efficiently producing dimethylnaphthalene by a single-step reaction which comprises cyclizing dehydrogenating 5-tolyl-penta-2-ene in the presence of a catalyst comprising in combination (a) a solid acid such as crystalline aluminosilicate, silica-alumina or alumina; (b) a noble metal such as palladium and platinum; and a carrier such as carbon, silicon oxide, titanium oxide and zirconium oxide. The process results in simplification of production, effective utilization of reaction heat and rationalization of the heat balance.

Process for producing dimethylnaphthalene

There is disclosed a process for producing a monoalkenylbenzene which comprises alkenylating a side chain of an aromatic hydrocarbon compound having at least one hydrogen atom bonded at .alpha.-position of the side chain (such as xylene) with a conjugated diene having 4 or 5 carbon atoms (such as butadiene) in the presence of a catalyst produced by calcining the mixture of a basic potassium compound and alumina and then heat treating the calcined product together with metallic sodium in an atmosphere of an inert gas. According to the aforesaid process, an industrially useful monoalkenylbenzene can be produced in high yield at a low cost with enhanced safety.

There is disclosed a process for producing a monoalkenylbenzene which comprises alkenylating a side chain of an aromatic hydrocarbon compound having at least one hydrogen atom bonded at .alpha.-position of the side chain (such as xylene) with a conjugated diene having 4 or 5 carbon atoms (such as butadiene) in the presence of a catalyst produced by calcining the mixture of potassium hydroxide and aluminum hydroxide and then heat treating the calcined product together with metallic sodium in an atmosphere of an inert gas. According to the aforesaid process, an industrially useful monoalkenylbenzene can be produced in high yield at a low cost with enhanced safety.

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Tsukuba, Japan

Makoto Takagawa