Mitsubishi Petrochemical Company Limited

Unicharm Corporation

Jgc Corporation

501 Mitsubishi Petrochemical Company, Ltd.

Takeshi Shibano

Kiichi Itoh

Kohei Sarumaru

Koju Kadowaki

Shuhei Yada

Yasuyuki Sakakura

Kiichi Ito

Kenji Yoshinaga

Katsunobu Yamaguchi

Kazuo Kikuchi

Etsuji Yamamoto

Teruo Nagai

Yoichi Ishii

Shinji Tsunoi

Isamu Yanai

Tateo Kurihara

Kazuhiko Higuchi

Tomoo Saito

Suguru Hamanaka

Yoji Kawatani

Tadahiko Kondoh

There is provided a process for producing a highly water absorptive polymer, which comprises making up a mixture (A) comprising an aqueous solution of (a) a partially neutralized product of acrylic acid with 20% or more of carboxylic groups being neutralized to an alkali metal salt or ammonium salt, (b) a crosslinking agent having two or more copolymerizable vinyl groups in one molecule, (c) a basic vinyl monomer in a quantity of 20 mol % or less based on said partially neutralized product of acrylic acid, (d) a nonionic surfactant with HLB of 7 or more and (e) an oxidative radical polymerization initiator, said mixture (A) being maintained at a temperature of 50.degree. C. or lower, and a mixture (B) comprising an amine or a reducing agent dissolved in water or in said mixture (A) from which at least the component (e) is removed, and mixing both the mixtures to cause polymerization.

Process for producing highly water absorptive polymer

Vapor phase catalytic oxidation of propylene into acrolein in the first step and then into acrylic acid in the second step has been improved (1) by utilizing as a diluent for the oxidation in the first step the effluent gas from the second step after the acrylic acid produced has been recovered therefrom and after it has been catalytically combusted and (2) by specifying operation conditions set in view of the recycle of the combusted 'waste' gas. The improved process, embodying the present invention, has made it possible to produce a high concentration of acrylic acid as both gas and condensation and also to prolong the catalytic activity of a Mo-Bi composite oxide catalyst used for the first oxidation reaction.

Process for production of acrylic acid

A process for the preparation of water absorptive resins which comprises supplying a solution containing at least 20% by weight of a water soluble ethylenically unsaturated monomer as a main component to a polymerization vessel accommodating a vapor phase comprising steam or a mixture of steam with at least one gas substantially inert with respect to polymerization, and polymerizing the monomer in the vapor phase under the relative humidity conditions in the vapor phase of 30% or more.

Process for the preparation of water absorptive resin

A shell-and-tube apparatus, more specifically, a shell-and-tube reactor, which includes a vessel, at least one intermediate tube plate sectioning the interior of the vessel into at least two compartments having different temperatures, a number of heat transferring tubes penetrating the intermediate tube plate or plates, and a fluid passing through the tubes which is heated or cooled by a heat transfer medium surrounding the tubes. At least one insulation plate or plates are provided on one or both sides of the intermediate tube plate so that the space between the intermediate tube plate or plates and, if two or more insulation plates are used, the space or spaces between the insulation plates may be utilized as a stagnation zone for the heat transfer medium, so as to make the temperature gradient through the intermediate tube plate or plates gentle and relax the thermal stress occurring in the body wall. The reactor is particularly useful for production of (meth)acrolain and/or (meth)acrylic acid by catalytic gas-phase oxidation of propylene or butenes.

Shell-and-tube apparatus having an intermediate tube plate

A process for producing a highly water adsorptive polymer, which comprises subjecting an aqueous solution of partially neutralized sodium acrylate wherein 20 to 50% or less of the carboxyl group has been neutralized to its sodium salt, the concentration of the partially neutralized sodium acrylate in the aqueous solution being 45 to 80% by weight, to solution polymerization in the presence of a crosslinking agent and optionally not exceeding 20 mol % based on the partially neutralized sodium acrylate of at least one basic vinyl monomer selected from the group consisting of (meth)acrylamide, N,N-dimethyl(meth)acrylamide, dimethylaminoethyl(meth)acrylamide, 2-vinylpyridine, and 4-vinylpyridine with the use of a water soluble radical polymerization initiator.

There is provided a process for preparing a water absorptive composite, which comprises the combination of the steps of (A) applying an aqueous solution containing (a) a polymerizable monomer comprising as a main component acrylic acid, of which 20% or more of the carboxyl groups have been neutralized to its alkali metal salt or ammonium salt, (b) a crosslinking agent, (c) a polyoxyethylene acyl ester with HLB of 7 or more and (d) an oxidative radical polymerization initiator to a prefabricated fibrous substrate and (B) polymerizing the polymerizable monomer applied to the fibrous substrate with addition of a reducing agent to form a composite of a polymer derived from the polymerizable monomer and the fibrous substrate.

Process for preparation of water absorptive composite

There is provided a process for preparing a water absorptive composite material, which comprises the combination of the following steps:

Process for preparation of water absorptive composite material

Propylene in admixture with molecular oxygen and steam is subjected to a two-step, vapor-phase, catalytic oxidation to convert into acrolein and then into acrylic acid. At least the first-step reaction is conducted in tubes of an apparatus of a shell-and-tube heat-exchanger type structure, and the reaction product of the first-step reaction is quenched before it is subjected to the second-step reaction. Reaction conditions in both the steps are specified.

Process for producing acrylic acid

There is provided a process for preparing a water absorptive composite material, which comprises the combination of the following steps of: (A) applying an aqueous solution of a polymerizable monomer comprising as a main component acrylic acid, of which 20% or more of the carboxyl groups have been neutralized to its alkali metal salt or ammonium salt, to a prefabricated fibrous substrate; (B) polymerizing the polymerizable monomers applied to said fibrous substrate to form a composite of a polymer derived from said polymerizable monomer and said fibrous substrate; and (C) adding to said composite a crosslinking agent having two or more functional groups reactive with the carboxyl groups and/or carboxylate groups contained in the polymer to react therewith.

A process for preparing a water absorptive composite consisting of a highly water absorptive polymer and a prefabricated fibrous substrate, which comprises applying an aqueous solution containing (a) a polymerizable monomer comprising as a main component acrylic acid, of which 20% or more of the carboxyl groups have been neutralized to its alkali metal salt or ammonium salt, (b) 2-vinylpyridine or(and) 4-vinylpyridine or(and) their salts, (c) a crosslinking agent and (d) an oxidative radical polymerization initiator to a prefabricated fibrous substrate, and then carrying out polymerization with addition of a reducing agent.

Acrolein and acrylic acid are produced by vapor-phase catalytic oxidation of propylene in a multi-tubular, fixed-bed reaction vessel with the use of a composite oxide catalyst represented by the formula Mo.sub.a Bi.sub.b Fe.sub.c A.sub.d B.sub.e C.sub.f D.sub.g Si.sub.h O.sub.x, wherein A, B, C, and D represent components selectable from respective groups of elements, and the subscripts a through h and x are specific numbers of atoms of respective elements and groups of elements. This catalyst is adapted and packed in each reaction tube in a manner such that its activity is controlled to increase from the inlet toward the outlet of the tube.

Process for producing acrolein and acrylic acid

Aqueous solution of alkali or ammonium acrylate is applied to a prefabricated fibrous substrate, and the acrylate is subjected to polymerization in two steps, namely the first step in which the acrylate is polymerized by means of a radical polymerization initiator and the second step which is subsequent to the first step and in which the unpolymerized acrylate is polymerized by means of heat treatment at 100.degree.-250.degree. C.

A process for producing a highly water-absorbing polymer, which comprises treating a water-absorbing polymer containing a carboxyl group and/or a carboxylate group with a silane coupling agent in the presence of water.

Process for producing highly water-absorbing polymer

Aqueous solution of alkali or ammonium acrylate is applied to a prefabricated fibrous substrate, and the acrylate is subjected to polymerization in two steps, namely the first step in which the acrylate is polymerized by means of a radical polymerization initiator and the second step which is subsequent to the first step and in which the unpolymerized acrylate is polymerized by means of irradiation with electromagnetic radiation or corpuscular ionizing radiation.

Process for the preparation of water absorptive composite material

A 1,2-unsaturated carboxylic acid or its ester such as acrylic or methacrylic acid or its alkyl ester is purified to remove aldehyde impurities contained therein by treating the acid or its ester with a mercapto containing compound in the presence of an acid catalyst.

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Yokkaichi, Japan

Takeshi Shibano