WO1996017853A1

WO1996017853A1 - Process for making hydrocarbyl (dihydrocarbyl) phosphates

Info

Publication number: WO1996017853A1
Application number: PCT/US1995/015634
Authority: WO
Inventors: Danielle A. Bright
Original assignee: Akzo Nobel N.V.
Priority date: 1994-12-07
Filing date: 1995-12-01
Publication date: 1996-06-13

Abstract

Hydrocarbyl (dihydrocarbyl) phosphate compounds can be made by reacting, in aqueous solution, a hydrocarbyl halophosphate with a water soluble salt of a hydrocarbyl diol. The hydrocarbyl moiety derived from the diol can be arylene-containing, such as being derived from resorcinol, hydroquinone, or bisphenol A. The hydrocarbyl halophosphate can be diphenyl chlorophosphate.

Description

PROCESS FOR MAKING HYDROCARBYL (DIHYDROCARBYL) PHOSPHATES

Bat- σround of the Invention

Hydrocarbyl (dihydrocarbylphosphate) compounds, which can be either "bis" phosphates, where "n" in the formula given below is 1, or oligotneric phosphates, where "n" is 2 or higher, or mixtures thereof, of the formula

RO- (P-0-A-0-P)_n-OR

RO OR

, here R is, preferably, either unsubstituted or substituted arylene and A is a bridging group containing arylene, two arylene groups joined by a bridging group (e.g., -C(CHj), - S0₂ or -CO) , a bridging group containing biarylene, or a bridging group containing unsubstituted or substituted al ylene, such as neopentyl, and n is, in the case of pure compositions an integer ranging from 2 to about 10, are a known class of flame retardant. In the case of mixtures, the value of n will usually be a decimal value within the above range.

One technique for formation of such compounds involves the initial reaction of a phosphorus oxyhalide (e.g., phosphorus oxytrichloride) with, for example, an aromatic diol (e.g., bisphenol A, resorcinol or hydroquinone) followed by the reaction of the resulting reaction product with aromatic hydroxy compound (e.g., phenol) . Examples of this route are described in U.S. Patent No. 2,520,090 and Japanese Patent Publication Nos. 89/31,544, 57/174,331 and 88/227,632. These routes are plagued by the large excess of phosphorus oxytrichloride needed to achieve the desired composition and the relatively long time needed to strip excess phosphorus oxytrichloride from the reaction vessel. Also, the stripping of phosphorus oxytrichloride for long periods of time at relatively high temperatures can result in an undesired change in the composition which results.

Triaryl phosphates (see U.S. Patent No. 4,290,977 to U. Hucks et al.) and bisphosphates (see U.S. Patent No. 5,183,905 to A.M. Aaronson et al. ) have been made by reacting an aqueous solution of a salt of a diol with a phosphorus halide compound in the presence of an organic solvent and a phase transfer catalyst. The use of an organic solvent constitutes a disadvantage from a disposal perspective.

Summary of the Invention

The present invention relates to the manufacture of hydrocarbyl (dihydrocarbyl) phosphate compounds, as depicted by the above formula, by reacting a monohydrocarbyl and/or dihydrocarbyl halophosphate with an aqueous solution of a salt of a hydrocarbyl diol in the substantial absence of organic solvent. The term "hydrocarbyl halophosphate" is intended to generically cover both the mono- and dihydrocarbyl-containing species described for use herein. The hydrocarbyl group and/or groups in the halophosphate can be either unsubstituted or substituted. The hydrocarbyl halophosphate, for example, can be an unsubstituted diaryl chlorophosphate, such as diphenyl chlorophosphate, a substituted chlorophosphate, such as dixylenyl chlorophosphate, dicresyl chlorophosphate, di (bromophenyl) chlorophosphate, and the like, a substituted or unsubstituted monoaryl dichlorophosphate, such as monophenyl dichlorophosphate, monocresyl dichlorophosphate, monoxylenyl dichlorophosphate, mono(bromophenyl) dichlorophosphate, and the like, or a mixture of substituted and unsubstituted mono- and diaryl chlorophosphates. The hydrocarbyl moiety derived from the diol can be arylene-containing, such as being derived from resorcinol, hydroquinone, bisphenol A, bisphenol S, 4,4' -biphenol, and the like.

Description of Preferred Embodiments

The hydrocarbyl (dihydrocarbylphosphate) compounds which can be made by the process of the present invention are of the formula given above.

The initial step of the instant process involves the dissolving of an appropriate diol of the formula HO-A-OH, where A is defined as set forth above in a caustic aqueous solution in the form of the water soluble salt thereof. This can most easily be accomplished by reaction of one equivalent of the diol with two equivalents of an alkali metal hydroxide, such as sodium hydroxide, in water. The use of an excess (5% to 30% excess) of alkali metal hydroxide (by weight excess) is desirable and gives better yield and purity of the produc . The resulting aqueous solution will contain the salt of the diol in a form suitable for the next step of the process.

The next step in the reaction involves the reaction of each equivalent of the aforementioned salt of the selected diol with two equivalents of a dihydrocarbyl halophosphate of the formula (RO)₂P(0)X, where R is as defined above and X is halo such as chloro.

The current process allows for the use of an aqueous solution or slurry of the salt of the diol thereby avoiding the need to handle a solid. The process is carried out in the presence of water without the use of a substantial amount (e.g., more than about 20%, by weight of the water) of organic solvent. A phase transfer catalyst may or may not be present in the reaction medium of the present invention.

The present invention will now be further exemplified by the Examples which follow.

EXAMPLE 1

To a suspension of 57.1 g of bisphenol A (0.25 mole) in 200 ml of water was added a solution of 24 g (0.6 mole) of sodium hydroxide in 50 ml of water. As expected, the addition is exothermic (final temperature: 37°C) . The slurry was cooled to 25°C. Diphenyl chlorophosphate (134.3 g, 0.5 mole) was added dropwise over two hours with the temperature being kept around 25°C. One could observe the formation of an organic layer. At the end of the addition, stirring was continued for an additional two hours. The mixture was allowed to separate. The organic layer was washed once with 200 ml of water. Removal of traces of water from the organic layer left 157.7 g of a viscous oil (91.1% yield) . Liquid chromatographic (LC) analysis of this material showed the following composition: 1.1% triphenyl phosphate, 10.7% of bisphenol A diphenyl phosphate (half- ester) , 83.5% of bisphenol A bis(diphenyl phosphate), the balance being the higher oligomers containing three (P₃) and four (P₃) phosphorus atoms.

EXAMPLES 2 - 8

In Examples 2 to 8, the effect of water concentration, quaternary ammonium transfer catalyst (ALIQUAT 336) , and sodium hydroxide concentration on the purity of the final product was studied. All reactions were carried out at room temperature. The yields were comparable. The results are summarized in Table 1:

in EXAMPLE 9

To a solution of 27.5 g of resorcinol (0.25 mole) in 100 ml of water was added a solution of 24.0 g (0.6 mole) of sodium hydroxide in 50 ml of water. As expected, the addition was exothermic (final temperature: 37°C) . The peach colored solution was cooled to 25°C. Diphenylchlorophosphate (134.3 g; 0.5 mole) was then added dropwise over a period of thirty minutes. Stirring was continued at room temperature overnight. On the following day the organic layer in the reaction mixture was washed with a 2 wt% caustic solution. After removal of the aqueous layer, 79.5 g of a yellow oil remained. Liquid chromatographic analysis of this layer indicated a mixture of 45.5 %, by weight, of resorcinol bis(diphenyl phosphate), 1.8 %, by weight, of triphenyl phosphate, with the remainder comprising resorcinol diphenyl phosphate and unreacted resorcinol.

EXAMPLE 10

In this Example, 50 ml of water was used to dissolve the same amount of resorcinol used in Example 9 and 0.6 g of a phase transfer catalyst (ALIQUAT 336 catalyst which comprises tricaprylyl methylammonium chloride) . The reaction was the same as described in Example 9 with 84.4 g of a yellow liquid being obtained as the organic layer. It comprised 70.4 %, by weight, of resorcinol bis(diphenyl phosphate) and 2.2 %, by weight, of triphenyl phosphate.

The foregoing Examples are presented for illustrative purposes only since they merely describe certain preferred embodiments of the present invention. The scope of protection sought is set forth in the claims which follow.

Claims

T riaim:

1. A process for making a hydrocarbyl (dihydrocarbyl) phosphate which comprises reacting, in aqueous solution in the substantial absence of an organic solvent, at least one hydrocarbyl halophosphate with at least one water soluble salt of a hydrocarbyl diol.

2. A process as claimed in Claim l wherein the hydrocarbyl moiety derived from the diol is arylene- containing.

3. A process as claimed in Claim 2 wherein the moiety is derived from a diol which is selected from the group consisting of resorcinol, hydroquinone, and bisphenol A.

4. A process as claimed in Claim l wherein the hydrocarbyl halophosphate is diphenyl chlorophosphate.

5. A process as claimed in Claim 2 wherein the moiety is derived from a diol which is selected from the group consisting of resorcinol, hydroquinone, and bisphenol A and the hydrocarbyl halophosphate is diphenyl chlorophosphate.

6. A process as claimed in claim l wherein the diol is selected from the group consisting of resorcinol, hydroquinone, and bisphenol A and the hydrocarbyl halophosphate is diphenyl chlorophosphate.

7. A process as claimed in Claim 1 wherein the hydrocarbyl halophosphate is monophenyl dichlorophosphate.

8. A process as claimed in Claim 1 wherein the hydrocarbyl halophosphate is a mixture of diphenyl chlorophosphate and monophenyl dichlorophosphate.

9. A process as claimed in Claim 2 wherein the moiety is derived from a diol which is selected from the group consisting of resorcinol, hydroquinone, and bisphenol A and the hydrocarbyl halophosphate is a mixture of diphenyl chlorophosphate and monophenyl dichlorophosphate.