Organic compounds -- part of the class 532-570 series – Organic compounds – Phosphorus esters
Reexamination Certificate
1997-06-09
2002-06-18
McKane, Joseph K. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Phosphorus esters
C558S114000
Reexamination Certificate
active
06407277
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for the preparation of a phosphoric monoester through the phosphorylation of an organic hydroxyl compound. More particularly, the present invention relates to a process for the preparation of a phosphoric monoester which can easily provide a phosphoric ester mixture having a high phosphoric monoester purity, a reduced orthophosphoric acid content, and good odor and hue.
2. Description of the Related Art
Phosphoric esters of organic hydroxyl compounds are used in a wide field as a detergent, a textile treating agent, an emulsifying agent, a rust preventive, a liquid ion exchanger and a medicament.
Although the reaction of an organic hydroxyl compound with phosphorus pentaoxide has been known as an industrial process for the preparation of a phosphoric ester in the prior art, the product of the reaction comprises mainly a nearly equimolar mixture of a phosphoric monoester represented by the following formula (A) and a phosphoric diester represented by the following general formula (B) (hereinafter, this mixture is referred to as “sesquiphosphate”):
wherein R represents a residue which is obtained by eliminating one hydroxyl group from an organic hydroxyl compound.
There are great differences in properties between a phosphoric monoester and a phosphoric diester. For example, alkali metal salts and alkanolamine salts of phosphoric monoesters of long-chain alkyl alcohols (e.g., lauryl alcohol) are soluble in water, excellent in foaming power and detergency, less toxic and lowly irritant to the skin to be useful as an excellent detergent, while alkali metal salts and alkanolamine salts of phosphoric diesters of long-chain alkyl alcohols are little soluble in water and exhibit foam inhibiting properties rather than little exhibit a foaming power. Therefore, a sesquiphosphate salt containing a large amount of a phosphoric diester salt is unusable as a highly foaming detergent.
Under these circumstances, the development of a process by which a phosphoric ester mixture having a high phosphoric monoester content can be prepared on an industrial scale safely and easily has been eagerly expected and the following processes have been reported to answer this expectation:
(1) a process which comprises reacting an organic hydroxyl compound with phosphorus oxychloride and hydrolyzing the obtained monoalkyl phosphoro-dichloridate;
(2) a process which comprises adding water to an organic hydroxyl compound and thereafter adding phosphorus pentaoxide to the obtained mixture to conduct phosphorylation with the amount of water preliminarily added being 0.5 to 3 mol per mol of phosphorus pentaoxide;
(3) a process which comprises reacting an organic hydroxyl compound with orthophosphoric acid and phosphorus pentaoxide (Japanese Patent Publication-B 42-6730, published on Mar. 18, 1967);
(4) a process which comprises reacting an organic hydroxyl compound with a condensed phosphoric acid (polyphosphoric acid);
(5) a process which comprises reacting an organic hydroxyl compound with a condensed phosphoric acid (polyphosphoric acid) and then recovering, concentrating and reusing excess phosphoric acid;
(6) a process which comprises reacting an organic hydroxyl compound with a phosphorylating agent comprising phosphorus pentaoxide, phosphoric acid and a polyphosphoric acid under such a condition that phosphoric acid components are excess, adding an organic hydroxyl compound to the obtained reaction mixture to make up to a stoichiometric amount and conducting further phosphorylation [see U.S. Pat. No. 4,350,645 (published on Sep. 21, 1982, assignee: Kao Corporation)]; and
(7) a process which comprises reacting an organic hydroxyl compound with phosphorus pentaoxide in the presence of water while blowing steam into the reaction system.
However, these processes have respective disadvantages as will now be described, being unsatisfactory as industrial processes for the preparation of phosphoric monoesters.
According to the process (1), three mol of hydrogen chloride is generated in order to prepare one mol of a phosphoric monoester. Accordingly, the process (1) is problematic in the disposal of hydrogen chloride and working atmosphere. Further, according to the process (1), an alkyl chloride is formed as a by-product owing to the presence of hydrogen chloride, so that it is difficult to enhance the phosphoric monoester content of the reaction product.
According to the processes (2) and (3), an organic hydroxyl compound comes into direct contact with highly active phosphorus pentaoxide from the first, though a small amount of water or orthophosphoric acid is present in the reaction system. Therefore, a sesquiphosphate containing a phosphoric diester is formed to lower the purity of the reaction product for a phosphoric monoester. Additionally, these processes have a disadvantage in that the phosphoric monoester formed is decomposed to cause the discoloration of the reaction product and the generation of a nasty odor. When an increased amount of water or orthophosphoric acid is used in order to lower the activity of phosphorus pentaoxide, the orthophosphoric acid content of the product is increased. The contamination of the product with orthophosphoric acid has undesirable influences on some fields, so that the use of the product is limited. For example, when monosodium salt of a phosphoric monoester of a long-chain alkyl alcohol is employed for a paste detergent, disodium phosphate is deposited due to the present of a large amount of orthophosphoric acid. The deposition of disodium phosphate is unfavorable in the use of the detergent.
According to the process (4), a phosphoric monoester can be selectively prepared. However, the amount of orthophosphoric acid formed as a by-product is nearly equal to the reciprocal of the average degree of condensation of the polyphosphoric acid used, so that the contamination of the product with orthophosphoric acid is unavoidable. Accordingly, the process (4) has the same problem as that of the processes (2) and (3). Further, the use of a polyphosphoric acid having an extremely high degree of condensation is necessitated in order to decrease the amount of orthophosphoric acid formed as a by-product according to the process (4). However, in the industrial preparation of such a polyphosphoric acid, the reaction system becomes highly viscous and the materials of the reactor are limited, so that the industrial preparation thereof is extremely difficult.
According to the process (5), a phosphoric monoester can be selectively prepared. Further, the process involves the recovery and reutilization of excess phosphoric acid, being industrially advantageous also in this respect. However, the process uses a large amount of phosphoric acid, so that the recovery thereof necessitates the shouldering of various heavy burdens and the use of considerably complicated equipment. Accordingly, the process cannot easily be conducted.
According to the process (6), the organic hydroxyl compound is added in two portions, so that the obtained reaction product has an enhanced ratio of a phosphoric monoester to a phosphoric diester. However, the reaction system tends to become highly viscous under the condition of an excess of the phosphorylating agent i.e., in the early stages of the reaction to necessitate the use of an industrially special reactor. According to the process (6), additionally, the decomposition of the phosphoric monoester formed proceeds, which lowers the yield of the phosphoric monoester and enhances the orthophosphoric acid content of the reaction product. The increase in the orthophosphoric acid content of the reaction product has undesirable influences on some fields, so that the use of the reaction product is limited.
According to the process (7), the ratio of the phosphoric monoester to the phosphoric diester can be enhanced by blowing steam into the reaction system. However, the blowing of steam into the reaction system increases the amount of orthophosphoric acid formed. Ac
Fujiu Akira
Matsunaga Akira
Nozaki Toshio
Tsuyutani Shinji
Ueda Masayuki
Kao Corporation
McKane Joseph K.
Saeed Kamal
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