WO2000020363A1

WO2000020363A1 - Novel bromine-containing 1,2-bis(phenyl) tetrafluoro ethanes and method of imparting flame retardancy to flammable materials

Info

Publication number: WO2000020363A1
Application number: PCT/US1999/022859
Authority: WO
Inventors: Charles J. Mazac; Leonard J. Chyall; Paul Kleindl; Mark L. Robin
Original assignee: Great Lakes Chemical Corporation
Priority date: 1998-10-07
Filing date: 1999-10-04
Publication date: 2000-04-13
Also published as: EP1119536A1; AU6409099A

Abstract

Bromine-containing 1,2-bis(phenyl) tetrafluoro ethanes of formula (I) wherein x=1-5, and y=0-5. Also, a method for the preparation of these compounds. The compounds of formula (I) are useful as intermediates in producing compounds exhibiting pharmaceutical or agricultural activity, and the compounds of formula (I) are useful as flame retardants.

Description

NOVEL BROMINE-CONTAINING l,2-BIS(PHENYL)TETRAFLUOROETHANES

AND METHOD OF IMPARTING FLAME

RETARDANCY TO FLAMMABLE MATERIALS

CROSS -REFERENCE TO RELATED APPLICATION

This application is a continuation- in part of U. S . Provisional Patent Application Serial No . 60/103 , 334 filed October 7 , 1998 .

FIELD OF THE INVENTION

The present invention relates to bromine- containing 1 , 2 -bis (phenyl) tetrafluoroethanes of the formula:

^Brχ-^ >^{~CF2 "CF2~ "Br} (I)

wherein x=l-5, and y=0-5. Also disclosed is a method for the preparation of these compounds . The compounds of formula I are useful as intermediates in producing compounds exhibiting pharmaceutical or agricultural activity, and the compounds of formula I are useful as flame retardants . BACKGROTND OF THE INVENTION AND PRIOR ART

Decabromodiphenyl alkanes (Cχ.₁₀) , such as decabromodiphenyl methane and decabromodiphenyl ethane are known compounds that are useful as flame retardants, as disclosed in Hussain U.S. Patent No. 5,008,477. The compounds are prepared by brominating diphenyl alkane, in the presence of a bromination catalyst such as A1C1₃ and/or AlBr₃, at a temperature of about 50°C to about 60°C, wherein the alkane group has 1-10 carbon atoms. It has been found, in accordance with the present invention, that the above- defined bromine-containing 1,2-bis (phenyl) tetrafluoro- ethylene compounds can be prepared and exhibit improved flame retardancy to flammable materials .

SUMMARY OF THE INVENTION

The novel compounds in accordance with the present invention have the general formula:

where : x is equal to 2-5, y is equal to 0-5; and x=l, y=l (for o,m' ; o,p'; and m,p' only). In the case of x=l and y=l, the ortho,ortho' , meta,meta', and para,para' compounds are known, but are novel as flame retardants . The compounds of formula I can be used as synthesis intermediates for the preparation of agricultural and pharmaceutical compounds, and can also be used as flame retardants.

DETAILED DESCRIPTION OF THE INVENTION

where : x is equal to 2-5, and y is equal to 0-5; and x=l, y=l_/ o,m' ; o,p'; and m,p' only (the symmetrical compounds for the case of x = 1 and y = 1 - the ortho-ortho¹ , meta-meta¹, and para-para' compounds - are known in the art per se, but not as flame retardants) .

The novel compounds are any of the following compounds :

Ci₄H₈F₄Br₂

/^Br /^Br /^{Br Br}\

<y>-CF₂-CF₂— (Q ; <^-CF₂-CF₂— (Q-Br , -CF₂ ^~CF₂— — ,

C]₄H₇F₄Br₃

C,4H₆F₄Br₄

Ci F-5FBr5

C₁₄H₄F₄Br₆

Br-(0)r-CF₂-CF₂— (Q}- t

C_MH₃F₄Br₇

C₁₄H₂F₄Br₈

C_MHF₄Br₉

C₁₄F₄Br.o

The compounds of formula I may be prepared in a number of ways. For example, the compounds may be prepared via the reaction of 1, 2-bis (phenyl) - tetrafluoroethane with a bromination agent, such as elemental bromine in fuming sulfuric acid:

wherein x=l-5; and y=0-5.

The amount of bromine reacted with the 1, 2-bis (phenyl) tetrafluoroethane reactant is readily controlled by adjusting the molar ratio of bromine to 1,2 -bis (phenyl) tetrafluoroethane. Excess bromine favors the formation of the more highly brominated compounds of the present invention, whereas lower amounts of bromine favor the production of the less heavily brominated compounds of the present invention.

Alternatively, as is taught in the prior art, different bromination agents may be employed, for example, elemental bromine in the presence of a Lewis acid, or N-bromo compounds such as N-bromosuccinimide and dibromodimethylhydantoin. The 1, 2-bis (phenyl) tetrafluoroethane precursor may be prepared via the reaction of benzil with a fluorination agent, such as SF₄ or diethylaminosulfur trifluoride (DAST)

All of the above-mentioned compounds are useful as flame retardants for use with any flammable material, as well as the following compounds:

where

X=0 or 1 and y=0 or 1 and x+y=l-2.

When used as a flame retardant for a flammable material, the bromine-containing 1, 2-bis (phenyl) tetra- fluoroethane should be incorporated into or onto the flammable material in an amount sufficient to obtain the desired flame retardancy, which varies with the particular flammable material in which the compound (s) is incorporated. In general, the amount of compound (s) incorporated into the flammable material is in the range of about 2% to about 50% by weight of flammable material, preferably about 5% to about 30%, based on the weight of flammable material .

The bromine-containing 1, 2-bis (phenyl) tetra- fluoroethanes of the present invention are useful for flame retardation of any flammable material , including monomers and oligomers, but are particularly advantageous for flame retarding thermoplastic and thermosetting polymers and copolymers. Examples include polyolefins, polyurethanes , polyamides, polyimides, polycarbonates, polyethers, polyesters, epoxy resins, polyphenols, and elastomers, such as natural rubber, butyl rubber, and polysilanes. The oligomers and polymers may be cross-linked or non cross-linked and may contain typical additives, such as plasticizers, stabilizers, antioxidants, fillers, pigments and the like. The flame retardant compounds of the present invention can be compounded into the flammable material at any stage of processing, e.g., added to the monomer or oligomer prior to, during, or after polymerization, or during extrusion, melt blending, or molding of the flammable material, e.g., polymer.

The following examples are provided for illustrative purposes only and should not be construed to limit the scope of the invention.

EXAMPLE 1

Preparation of 1, 2-bis (phenyl) tetrafluoroethane

To a mixture of benzil (1.07 g, 5.10 mmol) in CC1₄ was added diethylaminosulfur trifluoride (3.0 mL, 22.7 mmol) . The mixture was heated to reflux for 17 hours and the reaction mixture then cooled to room temperature and quenched with water. Aqueous sodium bicarbonate and dichloromethane were added and the two layers separated. The aqueous layer was washed with dichloromethane and the combined organic layers washed with brine, dried over MgS0₄, filtered and concentrated under reduced pressure. Chromatography of the crude product resulted in the isolation of 1.1 g (85% yield) of l, 2-bis (phenyl) tetrafluoroethane, identified from its ¹H, ¹⁹F and ¹³C NMR spectra.

EXAMPLE 2

Preparation of 1 , 2-bis (pentabromophenyl) tetrafluoroethane

To a flask charged with 1, 2 -bis (phenyl) tetra- fluoroethane (1.36 g, 5.35 mmol), prepared as described in Example 1, was added 34.7 g of 65% fuming sulfuric acid. Bromine (7.87 g, 49.5 mmol) was then added dropwise over a period of 30 minutes. The solution was then stirred for 4.5 hours at room temperature, and the reaction mixture then poured onto ice and the resulting mixture filtered. The recovered solid was washed with several portions of water and methylene chloride and identified by nuclear magnetic resonance (NMR) , mass spectrometry (MS) , Fourier Transform Infra Red (FTIR) , and bromine content analysis as 1, 2-bis (pentabromophenyl) tetrafluoroethane .

EXAMPLE 3

Employing the method of Example 2, but with lower bromine to 1, 2-bis (phenyl) tetrafluoroethane molar ratios (0.5-9 to 1), products of the current invention containing from 3 to 9 bromine atoms are readily prepared. EXAMPLE 4

Flame Retardancy Properties of 1,2 -bis (pentabromophenyl) tetrafluoroethane

This example demonstrates the flame retardancy properties of the 1, 2 -bis (pentabromophenyl) tetra- fluoroethane compound. A small-scale "Mini-Max" bowl mixer was employed to compound 1,2 -bis (pentabromophenyl) tetrafluoroethane (BPTFE) and 1, 2-bis (pentabromophenyl) ethane (BPE) , a commercially available flame retardant, into high impact polystyrene. The lower oxygen index (LOI) and the Underwriters Laboratories UL-94 rating were then determined for the samples. The results shown in Table 1 indicate that the flame retardant performance of the new compound is identical to that of the commercial product.

TABLE I

Compound LOI (% 0₂) UL-94 (Avg. burn in seconds)

BPTFE 25 V-0 (1)

BPE 25 V-0 (1)

Claims

WHAT IS CLAIMED IS;

1. Bromine-containing 1, 2 -bis (phenyl) tetra- fluoroethanes of the formula:

wherein x=2-5, and y=0-5; and x=l, y=l, o,m' ; o,p'; and m,p' .

2. A bromine-containing 1, 2 -bis (phenyl) tetra- fluoroethane according to claim 1, having a formula selected from the group consisting of

Br

3. A bromine-containing 1, 2-bis (phenyl) tetra- fluoroethane according to claim 1, wherein x=2-5 and y=0-5.

4. A bromine-containing 1, 2-bis (phenyl) tetra- fluoroethane according to Claim 3, having the formula:

Br₅-^-CF₂ - CF₂ —<^-Br₅

5. A bromine-containing 1, 2-bis (phenyl) tetra- fluoroethane according to claim 1, of the formula:

Br_x-^ -^CF2 - ^CF2 -^-Br_y

wherein x=3-5 and y=3-5.

6. A method of providing flame retardancy to a flammable material comprising incorporating into said flammable material a flame retardant-effective amount of a bromine-containing 1, 2-bis (phenyl) tetra- fluoroethane of the formula: Br_x-^^-CF₂ - CF₂ — <^-Br_y

wherein x=2-5, and y=0-5; and x=l, y=l, o,m' ; o,p'; and m,p' .

7. A method in accordance with claim 6 , wherein the flammable material comprises a polymer.

8. A method in accordance with claim 7, wherein the polymer is a polymer or copolymer selected from the group consisting of polyolefins, polyurethanes, polyamides, polyimides, polycarbonates, polyethers, epoxy resins, polyphenols, elastomers, polysiloxanes, and mixtures thereof.

9. A method in accordance with claim 6, wherein the bromine-containing 1, 2-bis (phenyl) tetra- fluoroethane is incorporated into the flammable material in an amount in the range of about 2% to about 50% by weight, based on the weight of the flammable material .

10. A method in accordance with claim 6, wherein the bromine-containing 1, 2 -bis (phenyl) tetra- fluoroethane is incorporated into the flammable material in an amount in the range of about 5% to about 30% by weight, based on the weight of the flammable material.

11. A method of making a bromine-containing 1,2 -bis (phenyl) tetrafluoroethane of the formula:

wherein x=l-5 and y=0-5

comprising brominating 1, 2-bis (phenyl) tetrafluoro- ethane by reaction of the 1, 2-bis (phenyl) tetrafluoroethane with a bromination agent.

12. A method in accordance with claim 11, wherein the 1,2-bis (phenyl) tetrafluoroethane is brominated with a bromination agent selected from the group consisting of elemental bromine, N-bromosuc- cinimide, dibromodimethylhydantoin, and mixtures thereof .

13. A method in accordance with claim 12 , wherein the bromination agent is elemental bromine.

14. A method in accordance with claim 13 , wherein the bromine is combined with a Lewis acid for contact and reaction with the 1, 2-bis (phenyl) tetra- fluoroethane .

15. A method in accordance with claim 11, further including the step of forming 1, 2 -bis (phenyl) - tetrafluoroethane by fluorinating benzil with a fluorination agent.

16. A method in accordance with claim 15, wherein the fluorination agent is selected from the group consisting of SF₄, diethylaminosulfur trifluoride, and mixtures thereof.

17. A method in accordance with claim 11, wherein the bromination agent is added to the

1,2 -bis (phenyl) tetrafluoroethane in a molar ratio in the range of 1 to 20 moles of bromination agent per mole of 1,2 -bis (phenyl) tetrafluoroethane.

18. A method in accordance with claim 17, wherein the 1, 2-bis (phenyl) tetrafluoroethane is formed by contacting benzil with 0.2 to 2 moles of fluorination agent per mole of benzil.

19. A method in accordance with claim 18, wherein the fluorination agent is diethylaminosulfur trifluoride.

20. A method in accordance with claim 19, wherein the diethylaminosulfur trifluoride is dissolved in an organic solvent .

21. A method in accordance with claim 20, wherein the organic solvent is carbon tetrachloride.