Mitsubishi Chemical Corporation

Mitsubishi Kasei Corporation

Mitsubishi Chemical Industries Limited

Yoshio Katsuro

Takashi Yamaguchi

Akira Utsunomiya

Hanako Kato

Keiichi Sato

Yutaka Mori

Keiji Yamahara

Hozumi Endo

Masaru Shimoyama

Hitoshi Matsuda

Akihiro Takazawa

Takayuki Yoshimori

Shoji Oishi

Takahiko Takewaki

Hiroshi Maeda

Masumi Hino

Hiroaki Nagai

Takanobu Katsuki

Takashi Moriyama

Toshifumi Yoshikawa

Mitsumasa Kitai

Shigenori Kawamura

Subjects for the invention are to obtain a quartz powder having a high purity and high quality and a process for producing the same and to obtain a glass molding formed by melting and molding the powder and extremely reduced in bubble inclusion. The invention provides a quartz powder, preferably a synthetic quartz powder obtained by the sol-gel method, which, upon heating from room temperature to 1,700&#xb0; C., generates gases in which the amount of CO is 300 nl/g or smaller and the amount of COis 30 nl/g or smaller.

High-purity quartz powder, process for producing the same, and glass molding

A method of producing a silica gel by hydrolyzing a silicon alkoxide and subjecting the resulting hydrogel to a hydrothermal treatment substantially without aging it is described. Also described in a silica gel produced by such a method and a silica gel which has the following characteristics:

Silica gel

A synthetic quartz powder obtained by calcining a powder of silica gel, characterized in that white devitrification spots having sizes of larger than 20 &mgr;m in diameter formed in an ingot obtained by vacuum melting the synthetic quartz powder at a temperature of from 1780 to 1800&deg; C. to form an ingot, followed by maintaining the ingot at a temperature of 1630&deg; C. for 5 hours, are at most 10 spots/50 g.

Silica gel, synthetic quartz glass powder and shaped product of quartz glass

Process for producing a high purity synthetic quartz

Processes for producing synthetic quartz powder and producing shaped

Process for producing synthetic quartz glass powder

Silica gel, synthetic quartz glass powder, quartz glass shaped product

The disclosure describes a process for producing halogenated phthalic anhydride, which comprises reacting phthalic anhydride with a molecular halogen in vapor phase in the presence of a catalyst containing zeolite as active component.

Process for producing halogenated phthalic anhydride

A process for producing a biphenyltetracarboxylic dianhydride which comprises the step of: heating phthalic anhydride at a temperature of from 135.degree. to 300.degree. C. in the presence of a palladium catalyst thereby to allow the phthalic anhydride to undergo a dimerization reaction. According to the process, biphenyltetracarboxylic dianhydride can be synthesized by the direct dimerization of phthalic anhydride.

Process for producing biphenyltetracarboxylic dianhydride

A process for dimerizing an aromatic halogen compound is disclosed, which comprises the step of: subjecting an aromatic halogen compound having at least one halogen atom bonded to an aromatic nucleus carbon to a dehalogenation-dimerization reaction in the presence of a catalyst, water, a reducing agent, and a halogen acceptor, the catalyst comprising a carrier supported thereon palladium and iron.

Process for dimerizing aromatic halogen compound

A method of dehalogeno-dimerizing an aromatic halide compound substituted by at least one halogen atom substituted on the aromatic ring using a palladium catalyst on support in the presence of water, a reducing agent and a halogen acceptor is disclosed. The method is characterized by using the palladium catalyst on support immersed in a hydrohalogenic acid prior to the dehalogeno-dimerization reaction.

Method for dimerization of aromatic halide compounds

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Kitakyushu, Japan

Yoshio Katsuro