Organic compounds -- part of the class 532-570 series – Organic compounds – Phosphorus esters
Reexamination Certificate
2001-08-08
2002-10-08
Vollano, Jean F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Phosphorus esters
C558S092000
Reexamination Certificate
active
06462216
ABSTRACT:
This application is the U.S. National Phase under 35 U.S.C. §371 of International Application PCT/JP00/00508, filed Jan. 28, 2000, which claims priority based on JP 1999-37480, filed Feb. 16, 1999.
TECHNICAL FIELD
The present invention relates to a process for producing phosphorohalidate (halogenated phosphoric acid ester).
BACKGROUND ART
Phosphorohalidates are chemical substances which are useful in a wide variety of fields as raw materials or intermediates for pharmaceutical preparations, agricultural chemicals and the like or as resin additives such as flame retardants, plasticizers and the like or intermediates thereof. For such uses, the purity should be as high as possible.
Phosphorohalidates are usually obtained by reacting a phosphorus oxyhalide with an aromatic hydroxy compound. A Lewis acid catalyst is often used for the purpose of suppressing the generation of the by-product triaryl phosphate during the reaction and increasing the reaction rate.
However, in such a method of producing phosphorohalidates, the crude product obtained from the reaction usually contains not only its reaction products, i.e., phosphorodihalidate and phosphoromonohalidate, but also the Lewis acid catalyst, the by-product triaryl phosphate, and the starting materials, i.e., phosphorus oxyhalide and aromatic hydroxy compound. As a result, in order to produce high purity phosphorodihalidate suitable for use as a pharmaceutical raw material or intermediate or as a reaction retarding agent for molding sand, etc., the crude phosphorohalidates obtained from the reaction (crude reaction product) need to be purified by distillation and each component contained in the crude reaction product needs to be isolated. However, when a crude reaction product containing a Lewis acid catalyst is distilled, a disproportionation reaction occurs during the distillation process. Two molecules of phosphorodihalidate tend to convert into one molecule of phosphoromonohalidate and one molecule of phosphorus oxyhalide. Two molecules of phosphoromonohalidate tend to convert into one molecule of phosphate and one molecule of phosphorodihalidate. Therefore, the purity and yield of the desired phosphorohalidate can not be substantially increased even through purification by distillation.
DISCLOSURE OF INVENTION
A primary object of the invention is to solve the above problem and provide a process for producing high-purity phosphorohalidate in a higher yield using a Lewis acid catalyst. The process can produce phosphorohalidate containing no impurities such as the phosphorus oxihalidate and aromatic hydroxy compound used as starting materials and the catalyst.
The present inventors carried out intensive research to solve the problem and found the following: when a crude reaction product obtained by reacting a phosphorus oxyhalide with an aromatic hydroxy compound in the presence of a Lewis acid catalyst is purified by distillation in the presence of an alkali metal salt, the disproportionation reaction is suppressed and the desired phosphorohalidate can be obtained in high purity and high yield by an economical and simple distillation process. The present invention was accomplished based on the above finding.
Specifically, the present invention provides the following processes for producing phosphorohalidate and for purifying the same.
1. A process for producing phosphorohalidate, the process being characterized in that a crude reaction product obtained by reacting a phosphorus oxyhalide with an aromatic hydroxy compound in the presence of a Lewis acid catalyst is purified by distillation in the presence of an alkali metal salt.
2. The process for producing phosphorohalidate according to item 1 wherein the alkali metal salt is an alkali metal carbonate.
3. The process for producing phosphorohalidate according to item 1 or 2, wherein 0.25 to 10 moles of the alkali metal salt is used per mole of the Lewis acid catalyst.
4. The process for producing phosphorohalidate according to any one of items 1 to 3, wherein the distillation for purification is carried out at a temperature of 20 to 230° C.
5. The process for producing phosphorohalidate according V to any one of items 1 to 4, wherein the phosphorohalidate is at least one member selected from the group consisting of diphenylphosphoromonochloridate and monophenylphosphorodichloridate.
6. A process for purifying phosphorohalidate, the process being characterized in that a mixture containing a phosphorodihalidate, a phosphoromonohalidate and a Lewis acid catalyst is purified by distillation in the presence of an alkali metal salt.
The process for producing phosphorohalidate according to the present invention is characterized in that the crude reaction product obtained by reacting a phosphorus oxyhalide with an aromatic hydroxy compound in the presence of a Lewis acid catalyst is purified by distillation in the presence of an alkali metal salt. In this description, this process is divided into two steps, i.e., a step for producing a crude reaction product from a phosphorus oxyhalide and an aromatic hydroxy compound (hereinafter referred to as “reaction step”) and a step for purifying the crude reaction product by distillation (hereinafter referred to as “purification step”), and is described below.
Reaction Step
In the reaction step, a phosphorus oxyhalide and an aromatic hydroxy compound are reacted in the presence of a Lewis acid catalyst.
Useful phosphorus oxyhalides include, for example, phosphorus oxychloride, phosphorous oxybromide and the like. Preferred is phosphorus oxychloride. The phosphorus oxyhalides can be used singly or in combinations of two or more.
Useful aromatic hydroxy compounds include, for example, compounds having an OH group directly bound to an aromatic ring such as a benzene ring, a naphthalene ring or an anthracene ring, i.e., aromatic compounds having a phenolic OH group. In addition, one to three substituents such as alkyl groups or halogen atoms may be bound to the aromatic ring. Two or more of the aromatic rings may be bound to each other with a single bond, an alkylene group, a sulfone group, etc. Alkyl groups useful as substituents on the aromatic rings include straight or branched chain alkyl groups having about 1 to 9 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, hexyl, heptyl, octyl, nonyl and the like. Useful halogen atoms include chlorine, bromine and the like.
Specific examples of aromatic hydroxy compounds include phenol, (o-, m- or p-)methylphenol, (o-, m- or p-)ethylphenol, (o-, m- or p-)n-propylphenol, (o-, m- or p-)isopropylphenol, (o-, m- or p-)n-butylphenol, (o-, m- or p-)sec-butylphenol, (o-, m- or p-)tert-butylphenol, (o-, m- or p-)isobutylphenol, (o-, m- or p-)tert-butyl-2-methylphenol, (o-, m- or p-)tert-butyl-4-methylphenol, (o-, m- or p-)pentylphenol, (o-, m- or p-)hexylphenol, (o-, m- or p-)heptylphenol, (o-, m- or p-)octylphenol, (o-, m- or p-)nonylphenol, (o-, m- or p-)chlorophenol, (o-, m- or p-)bromophenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)dimethylphenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)diethylphenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)di-n-propylphenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)diisopropylphenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)di-n-butylphenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)di-sec-butylphenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)di-tert-butylphenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)dichlorophenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)dibromophenol, (2,3,5-, 2,4,5-, 2,3,6-, 2,3,4-, 2,4,6- or 3,4,5-)trimethylphenol, (2,3,5- 2,4,5-, 2,3,6-, 2,3,4-, 2,4,6- or 3,4,5-)triethylphenol, (2,3,5-, 2,4,5-, 2,3,6-, 2,3,4-, 2,4,6- or 3,4,5-)tripropylphenol, (2,3,5-, 2,4,5-, 2,3,6-, 2,3,4-, 2,4,6- or 3,4,5-)tri-tert-butylphenol, (2,3,5-, 2,4,5-, 2,3,6-, 2,3,4-, 2,4,6- or 3,4,5-)trichlorophenol, (2,3,5-, 2,4,5-, 2,3,6-, 2,3,4-, 2,4,6- or 3,4,5-)tribromophenol, hydroquinone, resorcin, catechol, bisphenol A, bisphenol S, bisphenol F, (1- or 2-)naphthol, (2,2′-, 4,4′-, 2,3-)biphenol, (1-, 2- or 9-)anthracenol and the like. Her
Daihachi Chemical Industry Co. Ltd.
Knobbe Martens Olson and Bear LLP
Vollano Jean F.
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