Ube Industries, Inc.

Hideo Ishikawa

Hidetomo Ashitaka

Haruo Ueno

Nobunori Maehara

Norihumi Utada

Taiji Oda

Mikito Kashima

Nobuhiro Tsujimoto

Yumiki Noda

Kohei Nakajima

Kouichi Kashiwagi

Osamu Kimura

Kyohei Oizumi

Tetsuro Matsuura

Minoru Kono

Thunehiko Tokutomi

Shotaro Sugiura

Hideyuki Aikawa

There are disclosed a process for preparing 2-hydroxy-2-(6-methoxy-2-naphthyl)propionic acid or 2-hydroxy-(4-substituted phenyl)propionic acid derivative which comprises reacting 2-methoxynaphthalene or substituted benzene derivatives with pyruvic acid in the presence of a Lewis acid and then, if necessary, hydrolyzing the obtained product, and a process for preparing 2-(6-methoxy-2-naphthyl)propionic acid or 2-(4-substituted phenyl)propionic acid derivative which comprises reducing 2-hydroxy-2-(6-methoxy-2-naphthyl)propionic acid or 2-hydroxy-2-(4-substituted phenyl)propionic acid derivative in a lower aliphatic acid in the presence of an inorganic acid under hydrogen atmosphere by using a metal catalyst.

Processes for preparing 2-substituted propionic acid and derivatives

A polybutadiene rubber having an enhanced mechanical strength is produced in such a manner that the content of water in a solution of 1,3-butadiene in an inert organic solvent is controlled to 0.2 to 5 millemoles per liter of 1,3-butadiene; a first polymerization mixture is prepared from the controlled 1,3-butadiene solution, an organic aluminum compound of the formula Al R.sub.n X.sub.3-n, wherein R=C.sub.1-6 alkyl, phenyl, or cycloalkyl, X=halogen, and n=1.5-2.0, and a cobalt compound, for example, by aging a mixture of the controlled 1,3-butadiene solution with the aluminum compound for at least one minute and then by admixing the aged mixture with the cobalt compound; the first polymerization mixture is subjected to a cis-1,4-polymerization; a second polymerization comprising the resultant cis-1,4-polybutadiene, non-reacted 1,3-butadiene, the inert organic solvent, and a catalyst comprising an organic aluminum compound of the formula AlR.sub.3, a cobalt compound, and carbon disulfide is subjected to a 1,2-polymerization to produce a polybutadiene rubber consisting essentially of 5% to 30% by weight of a boiling n-hexane-insoluble fraction and 70% to 95% by weight of a boiling n-hexane-soluble fraction thereof and having an excellent mechanical strength; and after the 1,2-polymerization is shortstopped, the resultant polybutadiene rubber is isolated from the 1,2-polymerization mixture.

Process for producing polybutadiene rubber with enhanced mechanical

A polybutadiene rubber having an enhanced mechanical strength is produced in such a manner that the contents of water and carbon disulfide in a solution of 1,3-butadiene and carbon disulfide in an inert organic solvent is controlled to 0.2 to 5 m moles and 20 m moles or less, respectively, per liter of the 1,3-butadiene-carbon disulfide solution; a first polymerization mixture is prepared from the controlled 1,3-butadiene-carbon disulfide solution, an organic aluminum compound of the formula Al R.sub.n X.sub.3-n, wherein R=C.sub.1-6 alkyl, phenyl, or cycloalkyl, X=halogen, and n=1.5-2.0, and a cobalt compound, for example, by aging a mixture of the controlled 1,3-butadiene-carbon disulfide solution with the aluminum compound for at least one minute and then by admixing the aged mixture with the cobalt compound; the first polymerization mixture is subjected to a cis-1,4-polymerization; a second polymerization comprising the resultant cis-1,4-polybutadiene, non-reacted 1,3-butadiene, the inert organic solvent, an organic aluminum compound of the formula AIR.sub.3, a cobalt compound, and the carbon disulfide is subjected to a 1,2-polymerization to produce a polybutadiene rubber consisting essentially of 5% to 30% by weight of a boiling n-hexane-insoluble fraction and 70% to 95% by weight of a boiling n-hexane-soluble fraction thereof; and after the 1,2-polymerization is shortstopped, the resultant polybutadiene rubber is isolated from the 1,2-polymerization mixture.

Butadiene polymers containing 70% or more of 1,2-structure and a relatively low melting point are produced by polymerizing 1,3-butadiene in the presence of a catalyst which has been prepared by admixing (A) an organic solvent solution containing 1,3-butadiene, a cobalt compound and an organoaluminium compound; (B) an amide compound of the formula (2) or (3): ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are respectively an H atom, aliphatic hydrocarbon radical of 1 to 7 carbon atoms or aromatic hydrocarbon radical of 6 or 7 carbon atoms, R.sub.3 is H or an aliphatic hydrocarbon radical of 1 to 3 carbon atoms and n is 2 to 5, and; (C) carbon disulfide.

Method of producing 1,2-polybutadiene

A process for producing a polybutadiene is provided wherein, first, 1,3-butadiene is polymerized in the presence of a particular cis-1,4-polymerization catalyst and subsequently, the polymerization is continued in the presence of a particular 1,2-polymerization catalyst. The resulting polybutadiene is characterized as containing 2 to 40% of the 1,2-structure, the melting point of the 1,2-structure portion being 110.degree. to 215.degree.C, and containing 60 to 98% of the cis-1,4-structure and having an intrinsic viscosity [.eta.] of 0.9 to 8 in tetraline at 135.degree.C. A vulcanized product of the polybutadiene is characterized as possessing improved tear strength, flex-crack resistance and tensile strength.

Polybutadiene and process for producing same

Growing community of inventors

Chiba, Japan

Hideo Ishikawa