JPS6045168B2 - Polybromination method for bisphenoxyalkanes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Highly brominated arylalkyl ethers are useful as flame retardants for organic polymeric resinous materials.

Generally, the more bromination achieved on the aryl group, the more effective the compound is as a flame retardant. Until now, it has been difficult to bromine as many as three bromine atoms per phenyl group in bisphenoxyalkanes, and it has been difficult to bromine phenyl groups without cleaving one or both phenoxy-alkylene bonds in such bisphenoxy compounds. Complete bromination of the group was extremely difficult, if not impossible. For example, if elemental bromine is used as the brominating agent, hydrogen bromide is produced as a by-product, which decomposes the product formed.

Previously, the use of Lewis acids as catalysts for bromination also caused product decomposition. In both examples, cleavage of the phenoxy-alkylene bond occurred. Hydrogen bromide caused the formation of phenol, and Lewis acids promoted the formation of phenol salts. For example, when anisole is heated with aluminum chloride at 100°C for 2 hours, methyl chloride is generated and Cl. A] 0C6H5 remains (G. Beddeley, Journal of Chemical Society (J. Chem. SOc.), 194
4jf-. , p. 330). In the bromination of anisole, aluminum chloride (BOnneaud, Bull. SOc. Ch.
im. , Fr. )(4)7776), or iodine (A
．． I. Hashem, J.Appl.Chem.BiO
technOl. ), 2, 5, 197 bottles) as a catalyst, only pentabromophenol is recovered. Therefore, anisole cannot survive harsh bromination conditions. Those seeking to produce highly brominated arylalkyl ethers are therefore faced with a dilemma.
If conditions favoring significant bromination, such as strong Lewis acids or relatively high temperatures, are used, decomposition and cleavage of the phenoxy-alkylene bonds in the product will occur. If to avoid this, mild conditions such as no catalyst or a weak Lewis acid catalyst and relatively low temperatures are used, then low levels of bromination will occur. Therefore, the possibility of producing highly brominated bisphenoxy alkanes in a manner that neither decomposes the product nor cleaves phenoxy-alkylene bonds, especially in relatively high yields, would advance the technology. Probably.

According to the present invention, bisphenoxyalkanes having 2 or 3 carbon atoms in the alkane moiety are treated with a Lewis acid catalyst and a suitable chemical solution with a stoichiometric excess of bromine chloride to dissolve all of the compound. polybromination in the presence of an inert organic solvent.

Formula [wherein A is alkylene of 2 or 3 carbon atoms, R is alkyl up to and including 4 carbon atoms, x is 0, 1 or 2, and y is 3, 4 or 5 and z is 011 or 2].

R. ．． x. ．． It is understood that each of y and z may be the same or different on the phenyl group. Preferably, the Lewis acid catalyst is a metal halide Lewis acid catalyst capable of causing a Friedel-Crafts reaction;
Chemically inert organic solvents are chlorinated aliphatic hydrocarbons.

Generally, solvents without carbon-carbon unsaturated bonds are preferred. The method operates at temperatures ranging from about -10 to about 150°C and from about atmospheric pressure to about 14k9/CIL gauge (200p).
It may be carried out at a pressure of sig). at least 77
% product yields are possible, with yields of 90% and higher being common. The preferred product of this process is bis(
pentabromophenoxy)ethane. The process involves the use of both relatively strong Lewis acid catalysts and relatively weak ones. When using relatively strong Lewis acid catalysts, water is added to the solvent to destroy the catalyst after product formation and before its recovery. Given the components and conditions of this invention, only those bisphenoxyalkanes having 2 or 3 carbon atoms in the alkane moiety are useful. Alkanes with one or more carbon atoms have also been found to cleave at the phenoxy-alkylene bond.

The bisphenoxyalkanes used in the process may have alkyl and chloro substituents, for example as shown by formula 1 above. Similarly, some bromination may or may not be present in the raw materials used, although of course not to the extent that can be achieved by this method. The brominating agent is bromine chloride, which means a mixture of chlorine and bromine.

Bromine chloride is probably an equilibrium mixture of bromine, chlorine and bromine chloride. Preferably, bromine chloride is used in an anhydrous form. Bromination proceeds to virtually eliminate chlorination. Most or all of the chlorine present in the brominating agent is converted to HCl, which escapes as a gas. It is believed that the use of bromine chloride as a brominating agent significantly contributes to avoiding phenoxy-alkylene cleavage. Bromine chloride allows the process to proceed under milder conditions, such as lower temperatures, than when using bromine alone. Indeed, the method proceeds at room temperature. Bromine chloride also allows the use of weaker Lewis acid catalysts, which further contributes to avoiding cleavage of phenoxy-alkylene bonds. Methods for producing bromine chloride are known in the art.

Conveniently, bromine and chlorine are mixed in a closed container and the formed bromine chloride is removed from the liquid phase. Bromine and chlorine are each about 0
．． 7:1 to about 1.3:1, preferably about 0.9:1-1
．． A molar ratio of 1:1 may be used. Does the ratio of bromine to chlorine significantly exceed what is indicated? Katadodoro:! --=? ←=, which is the waste of HBr in this method.

If the bromine to chlorine ratio is significantly lower than indicated, chlorination of the bisphenoxyalkanes will proceed to a significant extent, preventing the achievement of the desired amount of bromination. Preferably, bromination and chlorine are used in a molar ratio of about 1:1. Any stoichiometric excess of bromine chloride relative to the bisphenoxyalkane is effective in promoting short reaction times and complete conversion. Generally, the excess bromine chloride relative to the bisphenoxyalkane is about 51 to about 50 rn0I% excess of the alkane. Lewis acid catalysts, such as iodine, are generally useful as catalysts in the present process.

However, preferred Lewis acid catalysts are metal halides that are capable of causing Friedel-Crafts reactions. Among these, aluminum is preferred;
Iron, antimony bromides and chlorides, and mixtures thereof, with antimony chloride being preferred. Specific examples of metal halide Lewis acid catalysts include SbCl3
, SbCl5, FeCl3, AlCl3, TiCl4,
TiBr4, Sncl2, SrlCl4, SrlBr4
, AlBr3, BeCl2, CdCl. , Zncl2,
BF3, BCl3, BBr3, GaCl3, GaBr3
, Zrcl4, BlCl3, UCl4 and Secl4
．． is included. Authoritative “Buck’s Chemistry Dictionary (Hack”S)
Chemical DiCtlOllary), 4th Edition, 1969, 10 It will be accepted to consider boron as a metal.

In any of the metals shown above like for example iron! It goes without saying that the metal may also be added directly to the reaction mixture in elemental form, or the metal may react with the bromine chloride odor or chlorine to form the catalyst. When following this procedure, the amount of bromine chloride used can be adjusted to suit the reaction. A catalytic amount of catalyst is used, which can be easily determined by trial and error.

The amount of catalyst and bromine chloride used appear to be related to each other in that a decrease in the amount of catalyst requires an increase in the amount of bromine chloride to achieve substantially the same amount of bromination, and vice versa. be. Generally, however, the catalyst employed may be in an amount ranging from about 5 to about 25 weight percent, preferably about 15 to about 2 weight percent of the bisphenoxyalkane. Both relatively weak Lewis acid catalysts and relatively strong ones can be used in this process.

For example, SbCl3, SbCl5, SbBr3, Sncl
Relatively weak or moderate Lewis acids such as 4 and TlCl4 are preferred. However, for example, AlCl3
, FeCl3, AlBr3, FeBr3 and BCl3
Relatively strong Lewis acids, such as, can be used if the Lewis acid is destroyed before recovering the product from the reaction mixture. This can be done by adding water to the mixture after stopping the bromination and before recovering the product. Water destroys the effects of strong Lewis acid catalysts. The product is finally recovered by distilling off the bromine chloride, organic solvent and, if added, water. If the strong Lewis acid is not destroyed, some of the product will turn into a tar-like substance during distillation. This safeguard of destroying the catalyst can be followed even when using relatively weak Lewis acid catalysts. If water is not added to destroy the catalyst, the product can be recovered by other methods such as filtration of the reaction mixture and washing and drying of the residue. The organic solvent must dissolve and be inert towards the indicated components of the reaction mixture.

It has been found that organic solvents free of carbon-to-carbon unsaturation and in particular carbon-to-carbon saturated chlorinated aliphatic hydrocarbons are suitable for this purpose. Carbon saturation in the solvent is primarily necessary to resist halogenation. However, the solvent need not be chlorinated. Certain useful solvents include carbon disulfide, nitromethane, nitroethane,
Includes carbon tetrachloride, chloroform, tetrachloroethane, methylene chloride, trichloroethane, dipromoethane, etc. Preferably the solvent is essentially anhydrous. Water apparently destroys the catalyst and causes the reaction to proceed at a slower rate. As used herein and in the claims, the term "solvent" includes one of the reactants itself, which fulfills the stated requirements of a solvent. For example, excess bromine chloride can itself act as a solvent. When carrying out the process, the solvent is first added to the reaction vessel, followed by the bisphenoxyethane and Lewis acid catalyst in any order, and finally the bromine chloride.

The brominating agent may be generated in situ or by metering the gaseous bromine and chlorine streams at any time immediately before addition to the reaction vessel. However, it is preferred to use preformed bromine chloride, which promotes faster equilibration and minimizes side reactions. The rate of addition of bromine chloride is not critical, as long as a stoichiometric excess is present at least at the end of the reaction to promote as complete a bromination as possible. As an example, a stoichiometric excess of bromine chloride can be added to the bisphenoxyalkane over a period of about 3 to 4 hours. Process conditions for liquid phase reactions are likewise not critical, except that subatmospheric pressures should not be used, which would lead to adverse effects. Otherwise, the pressure may range from about atmospheric pressure to virtually the physical limits of the equipment, practically up to about 14k9/Crl gauge. Pressures of about 3.5k9/Clt gauge to 7.0k9/d gauge are preferred. If the reaction is closed, the pressure will increase because it is spontaneous. If desired, the pressure in the reaction vessel can sometimes be slightly relieved by venting without adversely affecting the bromination reaction. Higher pressures tend to reduce the excess bromine chloride required. Similarly, although temperature is not critical, the temperature of the present method is about -10 to about 1
It may range from 50°C, with temperatures from about room temperature to about 50°C being preferred.

The reaction is complete in about 2 hours to about 2 turns, depending on conditions and reactants. A product yield of at least 77% is obtained. and often yields within the range of about 93% to about 98% are achieved. The type of compounds obtained as products according to the invention is shown above by formula 1.

Compounds of the desired type obtained by this method have the formula [wherein y
is 3, 4 or 5, z is 0, 1 or 2,
where y and z may be the same or different.

A preferred product is bis(pentabromophenoxy)ethane. The following examples merely illustrate the invention:
It should not be considered as imposing any limitations on the scope of the claims.

Example 1 When 1,2-diphenoxyethane is treated with bromine using an iron catalyst in the presence of an organic solvent at a temperature of 90° C., pentabromophenol is obtained with a yield of 90%.

When diphenoxyethane is treated with bromine using an antimony trichloride catalyst under mild conditions, i.e. at room temperature, the product 1,2-bis(dibromophenoxy)ethane is produced. Therefore, in the second reaction, some bromination occurred without the phenoxy-alkylene bond being broken. However, bromination was relatively low, consisting of only two bromine atoms on each phenyl group. Increasing the temperature of the second reaction to 90°C gave a complex mixture of many products. They contained some 1,2-bis(tribromophenoxy)ethane. However, diphenoxyethane is used in the present invention. Thus, treated with an organic solvent containing a stoichiometric excess of bromine chloride in substantially equimolar amounts, i.e. having a carbon-carbon saturated bond in the presence of antimony trichloride or aluminum trichloride. Time, 1
●2-Bis(pentabromophenoxy)thane was obtained in a yield of 93%.

Example 2 The following is a complete working example of one form of the invention.

To produce bromine chloride, an amount of 106.5 q of tetrachloroethane as a solvent was added to a 200 ml flask and cooled to a temperature in the range of about 5° C. with stirring.
Bromine in an amount of 53.2 g was then added followed by 31.2 y of chlorine through a gas sparger at a rate of 1.1 v/hr. In another flask, 127.5y of tetrachloroethane and 8.6y of 1,29-diphenoxyethane
was added and dissolved while stirring. This solution was filtered to remove a small amount of insoluble matter. Next, as a Lewis acid catalyst, 1.
2y of antimony trichloride was added. The furnace liquor and catalyst were added to the reaction vessel and 167.6 fI of bromine chloride solution prepared as first described was added to the solution at a temperature of about 18 - about 3
The mixture was added uniformly over about 3 hours while maintaining the temperature at 0°C.

The solution was then stirred for an additional 3 hours at room temperature. Two factors govern the rate of bromine chloride addition.

That is, there is a need to minimize the ability to dominate the exothermic reaction and the loss of brominating agent due to escaping HCl. Bromination involves electrophilic substitution of bisphenoxyalkanes without cleaving the phenoxy-alkylene bond.
Bromine chloride can be reacted under relatively mild conditions (at room temperature and below (below) to allow the reaction to proceed. At the same time, bromine chloride is economically advantageous compared to the use of bromine alone. The method eliminates the problem of oxidizing hydrogen bromide produced as an effluent from conventional bromination processes back to bromine and then recycling the bromine as the brominating agent. Following the reaction to create the polybrominated product,
The reaction mixture is heated sufficiently to distill off the excess bromine chloride into a standard laboratory trap containing the same solvent used in the reaction along with some solvent. During distillation, the temperature at the top of the still gradually decreases to the temperature of the solvent, about 147
The temperature rose to ℃. Distillation was stopped when a total of 60 ml had accumulated in the trap. At this stage there was no more bromine or chlorine in the reaction vessel. The absence of red vapor at the top of the reaction vessel or still can be taken as the end of distillation. The reaction mixture was then cooled to room temperature, filtered and
continue! The residue was washed with 128y of tetrachloroethane and it was filtered again. During this operation the solvent should be protected from water as it still contains the active catalyst. The residue from these offshore processes is dried offshore at approximately 100℃! The final product was obtained.

Yields from this operation ranged from about 92% to about 94% and above. The product is 1,2-bis(2,3,4,
It was mainly composed of 5,6-pentabenoxyethane, had a melting point of 312-316°C, and had a white to grayish white appearance. In place of the catalyst, solvent and other reactants indicated, any of the corresponding components previously identified could be used.

Example 3 A solution was made from 65 ml of 1,1,2,2-tetrachloroethane, 8.6 f (0.04 m01e) of diphenoxyethane and 0.25 ml of antimony pentachloride.

This solution was cooled in an ice bath, and 1.1.
2,2-tetrachloroethane 53f1 Bromine 26.9y (
A solution containing 0.34y atoms) and 13.4f of chlorine (0.38y atoms) was added. The mixture was stirred in an ice bath for 4 minutes and then for 2.5 hours at room temperature. 212 hours C~
29.4y of solid with a melting point of 218°C was collected.

It consisted primarily of 1,2-bis(2,4,6-tribromophenoxy)ethane and contained 72.4% bromine. Example 4 Bromine 432y (5.4y atoms), chlorine 211da (5.9y atoms)
y atom) and antimony pentachloride 22TrLt in 1.l
- A solution was made by adding to 540 mt of 2,2-tetrachloroethane.

1,2-diphenoxyethane 77.4y (0.36m0
Another solution was made by dissolving the sample in 260 ml of 1,1,2,2-tetrachloroethane.

The halogen solution was cooled in an ice bath and the diphenoxyethane solution was added to it over 37 minutes. Next, add 1 powder of the solution in an ice bath,
It was then stirred at room temperature for 2 hours and then left overnight. The generated precipitate was separated, washed first with 1,1,2,2-tetrachloroethane, then with methanol until the halogen was removed, and finally dried. 345.7 da of product with a melting point of 316-319°C was obtained (95.3% yield based on decabromodiphenoxyethane). Example 5 The amount used in this example was 4.3 g of diphenoxyethane (0
．． 02rT101), tetrachloroethane 21.7ml
, 0.6y of aluminum chloride and 0.30rT101 of bromine chloride in 30ml of tetrachloroethane.

The bromine chloride solution was added to ice-cooled diphenoxyethane over 1 hour and 38 minutes. The mixture was then heated to 40° C. for 1 hour, after which 10 ml of water were added and the mixture was stirred three times at room temperature. Excess bromine chloride was distilled off. The solvent was then steam distilled leaving the product as a slurry in water. The water was made hydrochloric acid by adding concentrated hydrochloric acid and the slurry was refluxed for 1 hour, filtered and washed with water. Melting point 308-313℃
A solid 19.3y was obtained with (96% yield based on decabromodiphenoxyethane). Example 6 1●1●2●2-tetrachloroethane 178.5y11
・2-bis(0-tolyloxy)ethane 9.69y(0
．． 04m01) and antimony trichloride 1.82% (0
．． 008rr 10 solutions were made.

The solution was cooled in a water bath, and the following 12 powders were added to it.
2,2-tetrachloroethane 77.5q1 bromine 38.4
y (0.48y atoms) and chlorine 17.3y (0.49y atoms)
y atoms) was added. The mixture was then stirred at room temperature for 12 minutes. Excess bromine chloride was distilled off and the mixture was finally cooled and filtered. 24.3y of solid was recovered with a melting point of 218-246°C. This solid contains bromine 70
．． 8%, giving a yield of 69.6% based on 1,2-bis(0-tolyloxytetrabromo)ethane.
Although some embodiments of the invention have been described above, it goes without saying that the invention may be practiced in other forms within the scope of the claims.

Claims (1)

[Claims] 1. In a method for polybromination of bisphenoxyalkanes that does not cleave either phenoxy-alkylene bond, a stoichiometric excess of bisphenoxyalkanes having 2 or 3 carbon atoms in the alkane moiety is used. Bromine chloride is reacted in the presence of a catalytic amount of a Lewis acid catalyst and a chemically inert organic solvent suitable to dissolve all of the above compounds to give the formula ▲ mathematical formula, chemical formula, table, etc. ▼ [formula Medium, A
is alkylene having 2 or 3 carbon atoms, R is alkyl with up to and including 4 carbon atoms, and x
is 0, 1 or 2, y is 3, 4 or 5, and z is 0, 1 or 2]. 2 The above bromine chloride is about 0.7:1 to about 1.3, respectively.
2. A method according to claim 1, comprising bromine and chlorine in a molar ratio of :1. 3 The above bromine chloride is about 0.9:1 to about 1.1, respectively.
Claim 1 consisting of bromine and chlorine in a molar ratio of :1.
The method described in section. 4. The method of claim 1, wherein the Lewis acid catalyst is a metal halide Lewis acid catalyst capable of causing a Friedel-Crafts reaction. 5. The method of claim 1, wherein the Lewis acid catalyst is selected from bromides and chlorides of aluminum, iron, antimony and mixtures thereof. 6 The Lewis acid catalyst is SbCl_3, SbCl_5,
FeCl_3, AlCl_3, TiCl_4, TiBr
_4, SnCl_2, SnCl_4, SnBr_4, A
lBr_3, BeCl_2, CdCl_2, ZnCl_
2, BF_3, BCl_3, BBr_3, GaCl_3
, GaBr_3, ZrCl_4, BiCl_3, UCl
4. The method according to claim 1, wherein the metal halide is selected from the group consisting of SeCl_4 and SeCl_4. 7. The method of claim 1, wherein the chemically inert organic solvent is a chlorinated aliphatic hydrocarbon having carbon-carbon saturated bonds. 8. Claim 1, wherein the chemically inert organic solvent is selected from the group consisting of carbon disulfide, nitromethane, nitroethane, carbon tetrachloride, chloroform, tetrachloroethane, methylene chloride, trichloroethane, and dibromoethane. the method of. 9. The method of claim 1, wherein said reaction is conducted at a temperature within the range of about -10 to about 150<0>C. 10. The method of claim 1, wherein said reaction is conducted at about atmospheric pressure to about 200 psig. 11 The above product is bis(pentabromophenoxy)
The method according to claim 1, wherein ethane is used. 12. The method of claim 1, wherein said excess bromine chloride is from about 5 to about 50 mol% excess of said bisphenoxyalkane. 13. The method of claim 1, wherein said chemically inert organic solvent is substantially anhydrous. 14 If the above Lewis acid catalyst is a relatively strong metal halide Lewis acid, and after the formation of the above product water is added to the solvent, the above water destroys the effect of the relatively strong catalyst, and the above 2. The method of claim 1, comprising the step of recovering the product by distilling off the solvent and water. 15. The method of claim 1, wherein the Lewis acid catalyst is a relatively weak metal halide Lewis acid, and the method includes the step of recovering the product by distilling off the solvent. 16. The method of claim 1, wherein said catalyst is present in an amount from about 5 to about 25% by weight of the bisphenoxyalkane. 17 In a process for polybromination of bisphenoxyalkanes that does not cleave either phenoxy-alkylene bond, bisphenoxyalkanes having two carbon atoms in the alkane moiety are each mixed in a mole ratio of from about 0.7:1 to about 1.3:1. and a catalytic amount of a metal halide Lewis acid catalyst capable of effecting the Friedel-Crafts reaction, and all of the above compounds are dissolved. reacting in the presence of a chemically inert chlorinated organic solvent suitable for carrying out the reaction, wherein the reaction is carried out at a temperature in the range of about -10 to about 150°C and at a pressure of about atmospheric pressure to about 14 kg/cm^2. Gauge (200psig
) at the pressure of the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, y is 3, 4 or 5, and z is 0, 1
or 2] with a yield of at least 77%. 18 Each of the above bromine chlorides is about 0.9:1 to about 1.
18. The method of claim 17 comprising bromine and chlorine in a 1:1 molar ratio. 19 The above product is bis(pentabromophenoxy)
18. The method of claim 17, wherein ethane is used. 20. The method of claim 17, wherein said chemically inert organic solvent is substantially anhydrous. 21. The method of claim 17, wherein said Lewis acid catalyst is selected from bromides and chlorides of aluminum, iron, antimony, and mixtures thereof. 22. The method of claim 17, wherein said chemically inert organic solvent is a chlorinated aliphatic hydrocarbon having carbon-carbon saturated bonds. 23. The method of claim 17, wherein said catalyst is present in an amount from about 5 to about 25% by weight of the bisphenoxyalkane.