Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
2000-02-14
2002-05-07
Wilson, James O. (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
Reexamination Certificate
active
06384267
ABSTRACT:
This application is based on patent application No. 11-39097 filed in Japan, the contents of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing hydroxyalkyl (meth)acrylates. Specifically, the present invention relates to an improved process which can commercially advantageously yield hydroxyalkyl (meth)acrylates from (meth)acrylic acid and alkylene oxides.
2. Description of the Prior Art
Hydroxyalkyl (meth)acrylates have been obtained by reacting (meth)acrylic acid with an alkylene oxide in the presence of a homogenous catalyst. Such homogenous catalysts include ferric chloride, iron hydroxide, and other iron compounds; chromium chloride and amine compounds; trialkyl amine, pyridine. However, such catalysts cannot be significantly separated from reaction mixtures for recycling, and are disadvantageous in cost efficiency.
These catalysts also serve to accelerate polymerization of the produced hydroxyalkyl (meth) acrylates. When the catalyst is transported into a distillation system for purification, it invites a distillation residue to polymerize thereby to become a gel, which will cause a blockage of equipment or other troubles.
As a possible solution to these problems, processes of using anion exchange resins as heterogenous catalysts have been proposed. For example, Japanese Examined Patent Publication No. 41-13019 discloses a process of using a catalyst comprising an ion exchange resin, most of whose ionic active groups are quaternary ammonium groups. Typical examples of the ion exchange resins used in this process are “DIAION® SA10A” (trade name: a styrene type anion exchange resin manufactured by Mitsubishi Chemical Corporation, Japan), and “Amberlite IRA-400” (trade name: a styrene type anion exchange resin manufactured by Rohm & Haas Co.).
Japanese Unexamined Patent Publication No.4-49265 discloses a process of using a catalyst comprising a strongly basic macroporous anion exchange resin having an acrylic backbone. Typical ion exchange resins used in the process include “Amberlite IRA-958 (trade name: an anion exchange resin manufactured by Rohm & Haas Co.), and “Lewatit AP-247-A” (trade name: an anion exchange resin manufactured by Bayer AG).
However, such known styrene type or acrylic type anion exchange resins have the following disadvantages.
The anion exchange resins having a trimethylammonium groups are known to be insufficient in heat resistance, and are believed to be used at temperatures of at highest about 50° C. to 70° C. In contrast, in the commercial production of hydroxyalkyl (meth)acrylates by the reaction of (meth)acrylic acid with an alkylene oxide, an optimum reaction temperature is 50° C. or higher, and reaction temperatures as higher as possible are desirable to increase reaction rates to thereby improve reaction yields. The anion exchange resins which are insufficient in thermal stability cannot be effectively used as catalysts.
Specifically, the anion exchange resins under reaction conditions at high temperatures are liable to release the trimethylammonium group serving as a reactive group, which rapidly deteriorates the catalytic activity with the passage of reaction time. In addition, reaction products are contaminated by trimethylamine derived from the anion exchange resins, which causes, for example, deteriorated coloring tone of end products.
In order to improve the heat resistance of the anion exchange resins, an anion exchanger has been proposed in Japanese Unexamined Patent Publication No. 4-349941, which anion exchanger comprises a benzene ring bonded through a polymethylene chain with an ammonium group.
When the polyalkylene chain is an ethylene chain the resin is liable to be subjected to Hofmann degradation (an elimination reaction of trimethylamine). If a dimethyl group is introduced at the &agr;-position to yield 1,1-dimethylethylene chain to thereby inhibit the Hofmann degradation, the heat stability of the anion exchange group is deteriorated due to the steric hindrance between the both methyl groups at the &agr;-position [J. Appl. Polym. Sci., 8.1659(1964)].
The processes of using known ion exchange resins as catalysts, in which the chemical or thermal stability of the ion exchange resins is inferior, cannot commercially yield hydroxyalkyl (meth)acrylates from (meth)acrylic acid and alkylene oxides in good yields.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to solve the problems inherent to the conventional equivalents and to provide a process for economically efficiently producing hydroxyalkyl (meth)acrylates without disadvantages such as deterioration in properties of a distillation residue (gelation), by the use of a specific anion exchange resin having satisfactory thermal and chemical stability as a catalyst.
Specifically, in the invented process for producing hydroxyalkyl (meth)acrylates by the reaction of (meth)acrylic acid with an alkylene oxide, an anion exchange resin is used as a catalyst, which anion exchange resin containing a repeating unit represented by the following formula (1) as a component:
wherein A is a straight chain alkylene group having 3 to 8 carbon atoms, each of R
1
, R
2
, and R
3
is a hydrocarbon group or an alkanol group having 1 to 4 carbon atoms, which may be substituted with a hydroxyl group, X
−
is a counter ion coordinated with an ammonium group, where the substituent A with the ammonium group may be substituted at any position of a benzene ring, and part of hydrogen atoms bonded to the benzene ring may be substituted with an alkyl group or a halogen atom.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention has a feature in that an anion exchange resin is used as a catalyst, which resin contains a repeating unit of the formula (1) as a component. As is apparent from the formula (1), the anion exchange resin for use in the invention can solve the problem of insufficient heat resistance in conventional anion exchange resins, by the introduction of a straight alkylene chain between an ion exchange group and a benzene ring. The anion exchange resin can therefore make (meth)acrylic acid to efficiently react with an alkylene oxide and can efficiently produce a hydroxyalkyl (meth)acrylate even at relatively high reaction temperatures.
The anion exchange resin for use in the invention having a repeating unit of the formula (1) is a polymer that is insoluble in a reaction system (a system in which reaction materials and products are present) of (meth) acrylic acid and an alkylene oxide. The substituent A in the formula (1) is a straight chain alkylene group having 3 to 8 carbon atoms.
The straight chain alkylene group A bonded to the ion exchange group is an essential element to improve the heat resistance of the ion exchange resin. If the number of carbons in the straight chain alkylene group A exceeds the above defined range, the constitutive unit of the formula (1) is to have an excessively large molecular weight, and an ion exchange capacity per unit mass is decreased to reduce the catalytic activity. Accordingly, the straight chain alkylene group A should have eight or less carbon atoms, preferably six or less carbon atoms. However, if the alkylene group A is an ethylene group or methylene group having two or less carbon atoms, the heat resistance is insufficient and a sustained satisfactory catalytic activity cannot be obtained. The straight chain alkylene group A must have three or more carbon atoms. Typically preferable examples of the alkylene group A are propylene group, butylene group, and pentylene group.
The alkylene group A having the ion exchange group may be substituted at any position of the benzene ring. The benzene ring in the formula (1) may be substituted with an alkyl group and/or a halogen atom. Such alkyl group include, but are not limited to, methyl group and ethyl group, and the halogen atom includes, for example, chlorine, bromine, and iodine atoms.
Each of groups R
1
, R
2
, and R
3
in the group [NR
1
R
2
R
3
Kubota Hirohisa
Shingai Yasuhiro
Ueoka Masatoshi
Watanabe Junya
Nippon Shokubai Co. , Ltd.
Oblon, Spivak, McClelland, Maier & Neustadt PC
Oh Taylor V
Wilson James O.
LandOfFree
Process for producing hydroxyalkyl (METH) acrylates does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for producing hydroxyalkyl (METH) acrylates, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing hydroxyalkyl (METH) acrylates will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2883026