Organic compounds -- part of the class 532-570 series – Organic compounds – Phosphorus esters
Patent
1996-07-24
1998-01-20
Anthony, Joseph D.
Organic compounds -- part of the class 532-570 series
Organic compounds
Phosphorus esters
558179, 562817, 562 24, 562819, C07F 902, C07F 928
Patent
active
057103089
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/JP95/00081 filed Jan. 25, 1995
FIELD OF THE INVENTION
The present invention relates to a process for producing organophosphorus ester compounds and to reactive flame retardants comprising said compounds. More particularly, the invention relates to a process for producing purified organophosphorus ester compounds which can be used as a bifunctional comonomer for imparting flame resistancy to polyester resin or as an intermediate thereof and to reactive flame retardants.
BACKGROUND OF THE INVENTION
As reactive flame retardants for polyester resin and other purposes, organophosphorus ester compounds such as phosphinylcarboxylic acid esters, etc. have heretofore been employed. Such organophosphorus ester compounds may contain alkylene glycols and other contaminants that can be used in polyesterification, but should have been purified to remove other impurities that would interfere with resin formation.
As the production technology for providing purified organophosphorus ester compounds, there is known a process which comprises preparing a purified organophosphorus carboxylic acid compound in the first place and, then, esterifying it with a lower alcohol to provide a purified organophosphorus ester compound.
For the production of an organophosphorus carboxylic acid compound, the following processes 1 and 2, among others, are known. In either process, a solid organophosphorus carboxylic acid compound is synthesized and the compound is then purified by rinsing with water. 1) A process for providing a purified compound which comprises reacting a dichlorophosphine derivative with (meth)acrylic acid in the presence of a catalyst such as an organic peroxide, hydrolyzing the reaction mixture, cooling the hydrolysate, and subjecting the resulting phosphinylcarboxylic acid crystals to filtration, aqueous rinse, and drying (for an improved yield, the filtrate is recrystallized) (U.S. Pat. No. 5,334,760).
2 A process which comprises reacting dichloro(phenyl)phosphine with an excess of acrylic acid, hydrolyzing the reaction mixture, cooling the hydrolysate, and subjecting the precipitated 2-carboxyethyl(phenyl)phosphinic acid to aqueous rinse and drying (U.S. Pat. No. 4,081,463).
However, when a rinse-purified organophosphorus carboxylic acid compound is esterified and used as a reactive flame retardant for polyester resin, the polyester resin is stained black. The probable cause for this trouble is that the organophosphorus byproduct compound remaining in the rinse-purified organophosphorus carboxylic acid compound affects the esterification catalyst to stain the resin.
The purity of the rinse-purified compound can be increased by recrystallization. The check experiment performed by the inventors of the present invention also affirmed a decreased organophosphorus byproduct content of the recrystallized compound. When a purified ester was produced from a recrystallization-purified organophosphorus carboxylic acid compound and used in the production of polyester resin, too, the problem of stained polyester resin could be overcome. However, addition of a recrystallization step results in commercial disadvantages such as lowered yield, prolonged production time, increased labor, and increased cost and, therefore, improvements have been awaited.
Having been developed in the state of the art described above, the present invention has for its first object to provide a commercially useful process for producing a purified organophosphorus ester compound expediently and in high yield. The second object of the present invention is to provide a reactive flame retardant comprising a purified organophosphorus ester compound provided by said process, which is suitable for a comonomer of polyester resin and other applications.
SUMMARY OF THE INVENTION
A process for producing an organophosphorus ester compound characterized in that 1 a reaction mixture (M1) available on reaction of a dichlorophosphine derivative (a) of the general formula (1)
R.sup.1 PC1.sub.2 (1) atoms! with (meth)acrylic acid (b
REFERENCES:
patent: 4081463 (1978-03-01), Birum et al.
patent: 4769182 (1988-09-01), Hazen
patent: 5153345 (1992-10-01), Knorr et al.
patent: 5153346 (1992-10-01), Knorr
patent: 5334760 (1994-08-01), Wachi et al.
Sataka Munekazu
Tanaka Keiji
Anthony Joseph D.
Sanyo Chemical Industries Ltd.
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