Mitsubishi Gas Chemical Company, Inc.

Mitsubishi Gas Chemical Company Co., Inc.

Yukio Sakai

Isao Mochida

Nobuyuki Koike

Kazuo Tanaka

Jitsuo Oishi

Hitoshi Sakamoto

Hiroyuki Otsuka

Yuzuru Takahashi

Koichi Kanno

Yasuhiro Hirai

Takahumi Yoshimura

Kyoko Shibahara

Takaaki Higashiizumi

Toru Tanaka

Takafumi Yoshimura

Susumu Fujiyama

Masatoshi Yoshimura

Masanori Hataya

Hiroyuki Ohtsuka

Yasufumi Hamada

Tsuneo Kosaka

Yasuhiro Shoji

A process for the production of carbon fibers, including melt-spinning mesophase pitch having an optically anisotropic content of at least 90%, a softening point of 190&deg; C. to 280&deg; C. and a heating weight loss of 0.7% by weight or less at a spinning temperature to form a spun fiber, infusibilizing the spun fiber to obtain an infusible fiber and carbonizing the infusible fiber.

Process for the production of carbon fibers

A method for preparing a modified optically isotropic pitch comprising, preparing a synthetic pitch by reacting a member selected from the group consisting of a conjugated polycyclic hydrocarbon containing a low molecular weight alkyl group or a material containing such a substituted hydrocarbon in the presence of hydrofluoric acid/boron trifluoride, and treating the synthetic pitch by passing an oxidizing gas through the synthetic pitch at elevated temperatures.

Method for producing isotropic pitch, activated carbon fibers and carbon materials for non-aqueous secondary battery anodes

A method of producing a phenol compound comprising a step of oxidizing an aromatic aldehyde to an aryl formate and an aromatic carboxylic acid with an oxygen-containing gas, and a step of decomposing the aryl formate to the phenol compound. To facilitate the separation of the aryl formate and the unreacted aromatic aldehyde, a mixture of the aryl formate and the unreacted aromatic aldehyde is recycled to the oxidation process to concentrate the aryl formate in the oxidation mixture. Alternatively, the oxidation process is carried out in an organic solvent having substantially no ability of dissolving water to increase the conversion of the aromatic aldehyde and the selectivity of the aryl formate, thereby producing the aryl formate in a high yield. In another method, the aryl formate is produced by oxidizing the aromatic aldehyde in the organic solvent having substantially no ability of dissolving water with performic acid generated in situ in the reaction system from the reaction between formic acid and hydrogen peroxide. Since the oxidation proceeds in the organic solvent, hydrogen peroxide in aqueous phase contact the aromatic aldehyde. This significantly reduces the amount of explosive cyclic perther and a high-boiling product.

Method of producing phenol compound

Method for producing isotropic pitch, activated carbon fibers and carbon

Pitch that is obtained from naphthalene derivatives having at least one methyl group and the content of an optically anisotropic phase in which is substantially 100% is disclosed. This mesophase pitch has a H/C atomic ratio of about 0.5-1.0 and an aromatic carbon ratio (fa) of at least about 0.7, contains methylic carbon in an amount of at least about 4% of the total carbon atoms, and has a softening point of 200.degree.-250.degree. C. The pitch contains about 12-20 mole % of molecules having an average molecular weight of less than about 600, about 55-70 mole % of molecules having an average molecular weight of from about 600-1,500 and about 20-30 mole % of molecules having an average molecular weight of higher than about 1,500. Fibers melt spun from this mesophase pitch can be converted to carbon or graphite fibers having high strength and modulus of elasticity by a heat treatment which consists of heating to a temperature of 200.degree.-350.degree. C. in an air atmosphere, then heating to about 1,000.degree. C. or higher in an inert gas atmosphere. Such mesophase pitch is produced by polymerizing a naphthalene derivative having at least one methyl group for about 5-300 minutes at a temperature of about 180.degree.-400.degree. C. and at a pressure of about 5-100 atmosphere in the presence of about 0.1-20 moles of HF and about 0.05-1.0 mole of BF.sub.3 per mole of the naphthalene derivative.

Mesophase pitch for use in the making of carbon materials

Pitch that is obtained from a condensed polycyclic aromatic hydrocarbon and the content of an optically anisotropic phase in which is substantially 100% is disclosed. This mesophase pitch has a H/C atomic ratio of 0.5-1.0, contains naphthenic carbon in an amount of at least 7% of the total carbon, and has a softening point of 180.degree.-400.degree. C. Fibers melt-spun from this mesophase pitch can be converted to carbon or graphite fibers having high strength and modulus of elasticity by a heat treatment which consists of heating to a temperature of 250.degree.-300.degree. C. in an air atmosphere, then heating to 1,000.degree. C. or higher in an inert gas atmosphere. Such mesophase pitch is produced by polymerizing a condensed polycyclic aromatic hydrocarbon for 5-300 minutes at a temperature of 180.degree.-400.degree. C. and at a pressure of 5-100 atmospheres in the presence of 0.1-20 moles of HF and 0.05-1 mole of BF.sub.3 per mole of the condensed polycyclic aromatic hydrocarbon.

Mesophase pitch for use in the making of carbon materials and process

A process for producing pitch useful as a starting material for the manufacture of a carbon material is provided. The pitch is produced by polymerizing a condensed nuclear aromatic compound or a material containing the same. The polymerization is carried out in the presence of a hydrogen fluoride/boron trifluoride catalyst system. The condensed nuclear aromatic compounds which may be used in this process are naphthalene, anthracene, phenanthrene, acenaphthene, acenaphthylene, pyrene and mixtures thereof.

Process for producing pitch used as starting material for the making of

A process for preparing pyromellitic dianhydride by dehydration of pyromellitic acid is disclosed. The dehydration is conducted in solid state by indirect heating. The characteristic feature of the process is that when the most part of pyromellitic acid was converted to the dianhydride, the remaining pyromellitic acid is dehydrated while regulating the temperature of the heating medium between 200.degree. C. and 235.degree. C. By this process, pyromellitic dianhydride with excellent quality, good color and free flowing property can be obtained easily, smoothly, and rapidly. A very simple apparatus can be used in the process and the apparatus can be constructed from cheap materials.

Process for preparing pyromellitic dianhydride

An aromatic polycarboxylic acid is produced by oxidation of an alkyl-substituted aromatic aldehyde or carboxyLic acid with molecular oxygen in water as a solvent in the presence of bromine ions or further together with heavy metal ions as a catalyst in a reactor using a zirconium material whose surface is coated with an oxide layer as a material of construction. The oxidation can be carried out in high yield without corrosion of the material of construction.

Process for producing aromatic polycarboxylic acid

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Tsukuba, Japan

Yukio Sakai