Phosphate ester composition and use

Abstract

A phosphate ester composition comprising more than 50 mass % of a phosphate ester represented by Formula 1, wherein X, Y, and Z are independently selected from the group consisting of alkyl, heteroalkyl, heteroaryl or aryl, with at least one of X, Y and Z being aryl, represented by Formula 2, and wherein two or more of R3, R4 and R5 have from 1 to 10 carbon atoms, and the total number of carbon atoms in R3, R4 and R5 is from 3 to 30. The use of the phosphate ester composition as a flame retardant, a lubricant, an anti-wear additive, a hydraulic fluid, a self-extinguishing functional fluid, or an additive thereof. ##STR00001##

Claims

1. A phosphate ester composition comprising more than 50 mass % of a phosphate ester represented by Formula 1, ##STR00014## wherein X, Y, and Z are independently selected from the group consisting of alkyl, heteroalkyl, heteroaryl or aryl, with at least one of X, Y and Z being aryl, represented by Formula 2, ##STR00015## and wherein two or more of R.sub.3, R.sub.4 and R.sub.5 are substituents having from 1 to 10 carbon atoms, and the total number of carbon atoms in R.sub.3, R.sub.4 and R.sub.5 is from 3 to 30, wherein the substituents R.sub.3, R.sub.4, and R.sub.5 of Formula 2 are different, wherein R.sub.2 and R.sub.6 are hydrogen, and wherein in the case of two of R.sub.3, R.sub.4 and R.sub.5 being substituents, the remaining R.sub.3, R.sub.4, or R.sub.5 is hydrogen.

2. The phosphate ester of claim 1, wherein at least two of X, Y and Z are aryl, represented by formula 2.

3. The phosphate ester of claim 1, wherein R3, R4 and R5 of Formula 2 have from 1 to 6 carbon atoms.

4. The phosphate ester of claim 1, wherein R3, R4 and R5 of Formula 2 have from 1 to 4 carbon atoms.

5. The phosphate ester of claim 1 wherein the total number of carbon atoms in R3, R4 and R5 is from 3 to 18.

6. The phosphate ester composition of claim 1 wherein the total number of carbon atoms in R3, R4 and R5 is from 3 to 12.

7. The phosphate ester of claim 1 wherein the aryl group of Formula 2 is selected from the group consisting of 3-methyl-4-ethylphenol, 3-methyl-4-propylphenol, 3-methyl-4-isopropylphenol 3-methyl-4-butylphenol, 3-methyl-4-tert-butylphenol, 3-methyl-4-sec-butylphenol, 3-methyl-4-iso-butylphenol, 3-methyl-4-pentylphenol, 3-methyl-4-hexylphenol, 3-methyl-4-sec-hexylphenol, 3-methyl-4-heptylphenol, 3-methyl-4-octylphenol, 3-methyl-4-sec-octylphenol, 3-methyl-4-nonylphenol 3-methyl-4-decylphenol, 3-methyl-5-isopropylphenol, 3-isopropyl-4-methylphenol, 3-ethyl-4-methylphenol, 3,5-dimethyl-4-ethylphenol, 3,5-dimethyl-4-propylphenol, 3,5-dimethyl-4-isopropylphenol, 3,5-dimethyl-4-butylphenol, 3,5-dimethyl-4-sec-butylphenol, 3,5-dimethyl-4-iso-butylphenol, 3,5-dimethyl-4-pentylphenol, 3,5-dimethyl-4-hexylphenol, 3,5-dimethyl-4-(1,1-dimethylpropyl)-phenol, 3,5-dimethyl-4-(1,1-dimethylbutyl)-phenol, 3,5-dimethyl-4-(1-ethyl, 1-methylpropyl)-phenol, 3,5-dimethyl-4-heptylphenol, 3,5-dimethyl-4-octylphenol, 3,5-dimethyl-4-nonylphenol, 3,5-dimethyl-4-decylphenol, 3,4-dimethyl-5-ethylphenol, 4-methyl-3-isopropylphenol, 3-isopropyl-4-methylphenol, 3-methyl-4-(1,1-dimethylpropyl)-phenol, 3-methyl-4-(1,1-dimethylbutyl)-phenol, 3-methyl-4-(1-ethyl,1-methylpropyl)-phenol.

8. The phosphate ester of claim 1 wherein the phosphate ester is represented by Formula 3: ##STR00016## wherein two or more of R.sub.3, R.sub.4 and R.sub.5 are substituents having from 1 to 10 carbon atoms, and the total number of carbon atoms in R.sub.3, R.sub.4 and R.sub.5 is from 3 to 30, and wherein the substituents R.sub.3, R.sub.4, and R.sub.5 are different, and wherein in the case of two of R.sub.3, R.sub.4, and R.sub.5 being said substituents, the remaining R.sub.3, R.sub.4, or R.sub.5 is hydrogen, two or more of R.sub.3, R.sub.4 and R.sub.5 are substituents having from 1 to 10 carbon atoms, and the total number of carbon atoms in R.sub.3, R.sub.4 and R.sub.5 is from 3 to 30, and wherein the substituents R.sub.3, R.sub.4, and R.sub.5 are different, and wherein in the case of two of R.sub.3, R.sub.4, and R.sub.5 being substituents, the remaining R.sub.3, R.sub.4, or R.sub.5 is hydrogen, two or more of R.sub.3, R.sub.4 and R.sub.5 are substituents having from 1 to 10 carbon atoms, and the total number of carbon atoms in R.sub.3, R.sub.4 and R.sub.5 is from 3 to 30, and wherein the substituents R.sub.3, R.sub.4, and R.sub.5 are different, and wherein in the case of two of R.sub.3, R.sub.4, and R.sub.5 being substituents, the remaining R.sub.3, R.sub.4, or R.sub.5 is hydrogen.

9. A phosphate ester composition comprising more than 50 mass % of a phosphate ester represented by Formula 4, ##STR00017## wherein Z is a hydrocarbyl or heterohydrocarbyl group having from 1 to 100 carbon atoms, n is 1, and X, Y, W and U are independently selected from the group consisting of alkyl, heteroalkyl, heteroaryl or aryl, with at least one of X, Y, U and W being aryl, represented by Formula 2, ##STR00018## and wherein two or more of R.sub.3, R.sub.4 and R.sub.5 are substituents having from 1 to 10 carbon atoms, and the total number of carbon atoms in R.sub.3, R.sub.4 and R.sub.5 is from 3 to 30, and wherein the substituents R.sub.3, R.sub.4, and R.sub.5 are different, wherein R.sub.2 and R.sub.6 are hydrogen, and wherein in the case of two of R.sub.3, R.sub.4, and R.sub.5 being substituents, the remaining R.sub.3, R.sub.4, or R.sub.5 is hydrogen.

10. The phosphate ester of claim 9 wherein the substituents R3, R4 and R5 of Formula 2 have from 1 to 6 carbon atoms.

11. The phosphate ester of claim 9 wherein the substituents R3, R4 and R5 of Formula 2 have from 1 to 4 carbon atoms.

12. The phosphate ester of claim 9 wherein the total number of carbon atoms in R3, R4 and R5 is from 3 to 18.

13. The phosphate ester of claim 9 wherein the total number of carbon atoms in R3, R4 and R5 is from 3 to 12.

14. The phosphate ester of claim 9 wherein the aryl group of Formula 2 is selected from the group consisting of 3-methyl-4-ethylphenol, 3-methyl-4-propylphenol, 3-methyl-4-isopropylphenol 3-methyl-4-butylphenol, 3-methyl-4-tert-butylphenol, 3-methyl-4-sec-butylphenol, 3-methyl-4-iso-butylphenol, 3-methyl-4-pentylphenol, 3-methyl-4-hexylphenol, 3-methyl-4-sec-hexylphenol, 3-methyl-4-heptylphenol, 3-methyl-4-octylphenol, 3-methyl-4-sec-octylphenol, 3-methyl-4-nonylphenol 3-methyl-4-decylphenol, 3-methyl-5-isopropylphenol, 3-isopropyl-4-methylphenol, 3-ethyl-4-methylphenol, 3,5-dimethyl-4-ethylphenol, 3,5-dimethyl-4-propylphenol, 3,5-dimethyl-4-isopropylphenol, 3,5-dimethyl-4-butylphenol, 3,5-dimethyl-4-sec-butylphenol, 3,5-dimethyl-4-iso-butylphenol, 3,5-dimethyl-4-pentylphenol, 3,5-dimethyl-4-hexylphenol, 3,5-dimethyl-4-(1,1-dimethylpropyl)-phenol, 3,5-dimethyl-4-(1,1-dimethylbutyl)-phenol, 3,5-dimethyl-4-(1-ethyl,1-methylpropyl)-phenol, 3,5-dimethyl-4-heptylphenol, 3,5-dimethyl-4-octylphenol, 3,5-dimethyl-4-nonylphenol, 3,5-dimethyl-4-decylphenol, 3,4-dimethyl-5-ethylphenol, 4-methyl-3-isopropylphenol, 3-isopropyl-4-methylphenol, 3-methyl-4-(1,1-dimethylpropyl)-phenol, 3-methyl-4-(1,1-dimethylbutyl)-phenol, 3-methyl-4-(1-ethyl,1-methylpropyl)-phenol.

Description

DESCRIPTION OF EMBODIMENTS

(1) The phosphate esters of the present invention are produced by methods which are well known in the art. Firstly, an alkylated phenol (cresol, xylenol, ethylphenol) is produced by alkylation of phenol (cresol, xylenol, ethylphenol) and/or by isomerisation of an alkylated phenol (cresol, xylenol, ethylphenol). U.S. Pat. No. 3,576,923, incorporated herein by reference for all purposes, discloses the alkylation of phenol with propylene to produce alkylated phenol. Those versed in the art will recognize that alkylating phenols can be accomplished via catalysed reaction of phenolic compounds with olefins and/or alcohols. The placement of substituents is directed by the orientation to the phenoxy group. Direct alkylation is limited to substituting the 2, 4, and/or 6 positions (Formula C) of the phenolic ring. It is commonly known that by adjusting the catalyst and conditions, the 2, 4, and/or 6 position can be favoured or disfavoured for alkyl substitution. Additionally the selection of olefin and/or alcohol reactant can have similar affect on the location (2, 4, and/or 6) of the alkyl substituent. Once prepared, the positional isomers (ortho, para) can be separated via distillation, crystallisation, and/or extraction.

(2) Substituents at the meta (3, and/or 5) positions are not produced as a normal course of alkylation, but rather as the product of isomerisation. Isomerisation catalysts are known e.g. as disclosed in U.S. Pat. No. 3,936,410, incorporated herein by reference for all purposes, and some have the ability to both alkylate and isomerise. The alkylated phenol is then subjected to phosphorylation to yield the phosphate ester.

EXAMPLES

(3) The Invention will now be described with reference to the following non limiting examples.

(4) In the Examples:

(5) GC means gas chromatography, Hewlett-Packer (HP) 7890 GC System with G4513A series injector (1.0 L @ 250 C. (100:1 split), Open Lab control software, 50M0.20 mm ID0.50 m HP-PONA (100% dimethylpolysiloxane), 1.0 L/min (constant flow mode) Helium, 40 C. (5 min hold) 10 C./min ramp rate to 310 C. (28 min hold), detection via flame ionization detector (FID) with air@ 450 mL/min, Hydrogen@ 35 mL/min, makeup Nitrogen@ 30 mL/min.

(6) LCMS means liquid chromatography mass spectrometry, Thermo Ultimate-3000 Ultra High Performance Liquid Chromatography (UHPLC), Thermo Accucore RP-MS 50 mm (length)2.1 mm (diameter)2.6 micron column with water/acetonitrile as the mobile phase gradient programmed to 100% acetonitrile, flow rate of 0.3 cc/min, Advion CMS Expression single quadrapole, time of flight (tof), atmospheric pressure chemical ionization (APCI), positive ion (+) mode, mass scan range from 250-600 atomic mass units (amu).

(7) HPLC means high performance liquid chromatography, Thermo U-3000 Ultra High Performance Liquid Chromatography (UHPLC), UV detection at 254 nm, 5 L sample volume, ACE C18-PFP (ACE C18-PFP is a C18 bonded HPLC column with a pentafluorophenyl (PFP) phase), 150 mm (length)4.6 mm (diameter)3 micron, mobile phase 100% methanol at 0.2 ml/min, UV detection at 254 nm, 5 L sample volume.

(8) The melting point was measured via differential scanning calorimetry (DSC, TA instrument DSC Q20), standard cell, 10 C. ramp rate to 100 C., 1 C./min ramp rate to 90 C., 10 C./min ramp rate to 140 C.

(9) The kinematic viscosity was measured using an Anton Paar SVM 3000 Viscometer following American Society for Testing and Materials (ASTM) test method D7042-Standard Test Method for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic Viscosity).

(10) The pour point was measured via an iSL CPP 5Gs, following ASTM test method D97Standard Test Method for Pour Point of Petroleum Products.

Comparative Example 1Synthesis of Tri-Cresyl Phosphate Ester (TCP)

(11) ##STR00010##

(12) A commercial sample of mixed m-,p-cresol (46% m-cresol, 53% p-cresol) was obtained and confirmed to be 99% m-,p-cresol (GC). This material was used as is without further purification. In a 1 litre reaction flask, 324 g of m-,p-cresol (MW-108, 3 moles), 93 ml of phosphorus oxychloride (MW-153.33, 1 mole), 3.838 g magnesium chloride and 6.1 g boiling chips were introduced. The reaction mixture was stirred and heated to 200 C. for over 4 hours. Once at this temperature the mixture was held at 200 C. for an additional 1 to 2 hours until there were no signs of ongoing reaction (i.e. no bubbling observed in the reaction flask). The reaction product was allowed to cool to at least 150 C. before proceeding to the purification step. The reaction product was purified by vacuum distillation. Fractions collected during the distillation were analysed by LCMS and HPLC to determine composition. Fractions of acceptable triaryl phosphate ester quality were recombined (290 g, 80% yield) and used for evaluation.

Comparative Example 2

(13) Using a method similar to that outlined in Comparative Example 1 but with a different feedstock as shown in Table 1, the phosphate ester:(Tri-xylyl phosphate ester [TXP]) was synthesized.

(14) ##STR00011##

Comparative Example 3

(15) Using a method similar to that outlined in Comparative Example 1, but with a different feedstock as shown in Table 1, the phosphate ester (Tri-p-tert-butylphenol phosphate ester [TBPP]), was synthesized

(16) ##STR00012##

Example 1

(17) Using a method similar to that outlined in Comparative Example 1, but with a different feedstock as shown in Table 1, the phosphate ester 4 (Tri-3-methyl-4-propylphenol phosphate ester was synthesized.

(18) ##STR00013##

(19) The Properties of the phosphate esters made as per the Examples are summarised in Table 1.

(20) TABLE-US-00001 TABLE 1 Phosphate Ester Examples Example 1 Comparative Comparative Comparative Novel Example 1 Example 2 Example 3 Phosphate TCP TXP TBPP Ester R2 Substituent None None None None R3 Substituent Methyl (53%) Methyl None Methyl R4 Substituent Methyl (47%) Methyl t-Butyl i-Propyl R5 Substituent None Methyl None None R6 Substituent None None None None Total number of carbon atoms in 1 2 4 4 R3, R4 and R5 Feedstock m-,p-cresol Xylenols p-tert-butyl 3-methyl-4- phenol isopropyl phenol Phenol Co-feed, % 0 0 0 0 Purity, % >98 >98 Yield, % Form @ Ambient Temperature, Liquid Liquid Solid Liquid 25 C. Melt Point.sup.1, C. 104 Kinematic Viscosity.sup.2 @ 40 C., cSt 22 42 332 Kinematic Viscosity.sup.2 @ 100 C., cSt 4 5 13 Pour Point.sup.3, C. 33 25 7 .sup.1melting point measured via differential scanning calorimetry (DSC, TA Instruments DSC Q20) .sup.2kinematic viscosity measured using an Anton Paar SVM 3000 Viscometer .sup.3pour point measured via an iSL CPP 5Gs, following ASTM D97

(21) The applicant has found (Example 1) that by eliminating substituents at the 2, and/or 6 position that regulatory neurotoxicity concerns are addressed, and that by varying the i) number (at least two), ii) location (3, 4, and/or 5) and iii) size of substituents that improvements in physical properties (like viscosity and pour point, Table 1) can be realized versus mono-substituted aryl phosphate esters. Otherwise solid 4-monoalkyl aryl(phenyl) phosphate esters can be redesigned into room temperature liquids of less than 0 C. pour point while maintaining equivalent molecular weight.

(22) Furthermore, the improvement in certain physical properties does not come at the expense of properties like volatility, boiling point, or acute toxicity (GHS Classification). Additionally, the improved viscosity reduces the need to add phenyl groups, which are prone to hydrolysis and have acute toxicity (marine pollutant) issues.

(23) The effect of multiply substituted 3, 4, and/or 5 aryl groups on the finished phosphate ester is not discernible from the physical characteristics of the starting materials, (see Table 2).

(24) TABLE-US-00002 TABLE 2 Physical Properties of Alkyl Phenols. Melt Boiling Alkyl Phenol M.W. Point, C. Point, C. C4 4-Tert-Butyl Phenol 150 98 237 4-Isopropyl-3-MethylPhenol 150 110 238

(25) Although specific embodiments of the invention have been described herein in some detail, this has been done solely for the purposes of explaining the various aspects of the invention, and is not intended to limit the scope of the invention as defined in the claims which follow. Those skilled in the art will understand that the embodiment shown and described is exemplary, and various other substitutions, alterations and modifications, including but not limited to those design alternatives specifically discussed herein, may be made in the practice of the invention without departing from its scope.