CA1062284A - Halogenated halocyclopentadiene adducts of norbornenes - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Halogenated derivatives of the Diels-Alder adduct of norbornene and halocyclopentadiene have the formula -

Description

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Back~round of the Invention In recent years, the lncreasing use of normally flammable polymers for a variety of purposes has led to the lncreased need and development of fire retardant addltives. In particular, a need has developed for fire retardant additives whlch may be economlcally ~ produced and whlch may be readily incorporated into polymeric com-i~ positions for use in the production of molded or extruded articles.
Although the prior art discloses the preparatlon of the mono- and di- halogen derivatives of the monoadducts of hexahalogenated cyclopentadlene and norbornene or norbornadiene and thelr use as lnsecticldes, the prlor art does not disclose the chloro-bromo derivatives or various other polyhalogenated derivatives, nor their use as fire retardant additives to polymer compositions.
Accordingly, it is an object of the present invention to provide novel and useful halogenated derivatives of the monoadducts of halocyclopentadiene and norbornene or norbornadiene.
It is a further ob~ect to provide novel compounds which may be readily incorporated into normally flammable polymeric molding or . extruding compositions to render such compositions fire retardant.
The Prior Art It is known to prepare the monoadduct of norbornadiene and hexachlorocyclopentadiene. The resulting adduct and its use as an insecticide is disclosed in USP 2,635,977. The bromination of the monoadduct at 0 degrees Celsius with elemental bromine is disclosed in J. Chem Soc. 3669 (1960). Bromination at 65 degrees Celsius in : i the presence of ultraviolet light is disclosed in British Patent 692,546 ' and in USP 2,676,131. British Patent 692,546 also discloses the chlorination of the monoadduct. Various other routes to the preparation of dichloro derivatives of the monoadduct of norbornadiene and hexa-chlorocyclopentadiene are disclosed in the art, see, e.g. USP 2,911,411, . .

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1C~6Z284 USP 2,80~,420, and British Patent 714,688.
It is known al~o to prepare the monoadduct of nor-bornene and hexachlorocyclopentadiene and to monohalo~enate the adduct in the presence of light. See Cristol et al, J.
Org. Chem., 29, 1279 (1964). Various other syntheses of this no-chloro derivative and its use as an insecticide are dis-closed in USP 2,635,979 and Gazz. Chem. Ital., 85, 1118 (1955).
Summary of the Invention The compounds of the present invention are characterized by the formula ~. .

X~
,. X ' wherein X and Y are chlorine, n has an average value of from 0 -~

to 6, m has an average value of from 0 to 6, the total of n plus .1 `, m is from about 2 to 6, with the proviso that when the total of n plus m is about 2, m is about 1 and n is about 1.

There are also disclosed compounds in which X is flourine, "t bromine or chlorine and Y i9 fluorine, chlorine, bromine, alkyl ., .
of 1 to 10 carbon atoms, alkyloxy wherein the alkyl group con-tains from 1 to 10 carbon atoms, haloalkyl and haloalkyloxy -; 20 wherein the alkyl groups contain from 1 to 10 carbon atoms and halo- is fluoro-, chloro-, or bromo.
These compounds may be prepared by reacting a nor-bornene or norbornadiene with a halocyclopentadiene of the ' ~tructure: X~

. ! X ~
.. , ~,, .

X
wherein X and Y are as defined above, thereafter reacting the resulting adduct with a halogenating agent such as sulfuryl A chloride, sulfuryl .

bromide, chlorlne, bromine, mixtures thereof and the like. As disclosed hereinafter, it ls sometlmes advantageous to run these halogenations ln the presence of a llghtor a free radlcal generatlng halogenation catalyst and recovering a halogenated norbornene halo-cyclopentadiene adduct of the above formula.
It has been found that such compounds are effective fire retardant additives to normally flammable polymer compositions.
Description of the Preferred Embodiment The preferred compounds of the present invention, based on the economics and ease of preparation as well as overall effectiveness as fire retardant additives, are those of the formula given hereinabo~e, wherein X and Y are chlorine, n has an average value of from 0 to about 2, m has an average value of from 0 to about 4, and the total of n plus m is from about 2 to about 4.
Halogenated cyclopentadienes suitable for use in the preparation : ~
of the adducts described above include hexahalocyclopentadienes, such as hexachlorocyclopentadiene, hexafluorocyclopentadiene and hexa-bromocyclopentadiene, monoalkyl-pentahalocyclopentadienes, such as l-methyl-pentachlorocyclopentadiene~ l-ethyl pentabromocyclopentadiene, l-hexyl pentafluorocyclopentadiene, l-decyl pentachlorocyclopentadiene;
dialkyltetrahalocyclopentadienes such as l~l-dimethyl tetrachlorocyclo-pentadiene~ l,l-dibutyl-tetrachlorocyclopentadienej l-methyl, l-hexyl-, tetrabromocyclopentadiene, l~l-dinonyl-tetrafluorocyclopentadiene, l,l-didecyl tetrachlorocyclopentadiene; alkoxy pentahalocyclopentadienes such as l-methoxy-pentachloro- and l,l-dimethoxy tetrachlorocyclo-- pentadiene, l-hexoxy pentabromo-~ and l-hexoxy, l-octoxy tetrabromo-cyclopentadiene, l-decoxy-pentachloro- and l,l-didecoxy-tetrachlorocyclo-pentadiene, l-ethoxy-pentafluoro~ and l-ethoxy, l-butoxy-tetrafluorocyclo-pentadiene; monohaloalkyl halocyclopentadienes such as l-chloromethyl-pentachlorocyclopentadiene, l~l-bis(chloro-methyl) tetrachlorocyclo-.

-4_ .:' . '': - -pentadiene, I-bromoethylpentabromocyclopentadiene, l,l-bis-(bromohexyl) tetrachlorocyclopeneadiene, l-fluorodecyl pentafluoro-cyclopentadiene, l,l-bis-(fluorodecyl) tetrafluorocyclopentadiene, l-chloromethyl, l-bromopropyl tetrabromocyclopentadiene. The preferred -halocyclopentadiene is hexachlorocyclopentadiene.
; The adduction step is preferably in liquid phase reaction.
Although the reactants may be combined directly, the reaction is - -preferably carried out in the presence of a solvent.
The solvent may be an excess amount, over the stoichio-metrical proportion, of either of the reactants or a solvent which ; is inert to the reactants and the reaction product may be used.
``J Preferably, the solvent should boil above about 90 degrees Celsius.
- Suitable non-reactive solvents include toluene, xylene, nitrobenzene, i methylcyclohexane, perchloroethylene, acetylene tetrachloride and the like.
The reactants may be employed in various proportions. When the reactants are a halocyclopentadiene and a norbornene, a molar ratio of one to one is preferred, but an ex¢ess, for example, 20 perecent, of either reactant can be employed. However, when the reactants are a halocyclopentadiene and 8 norbornadiene, it is preferred to employ at least about 100 percent excess of the norbornadiene to obtain maximum ` yields.
The temperature employed in the adduction step may range from about 75 degrees Celsius to about 200 degrees Celsius, although temperatures outside this ran8e can be used. Preferably, the adduction reaction is effected at about 85 degrees to about 170 degrees Celsius. The time required for the adduction to go , essentially to completion may vary according to the reactivity of the halocyclopentadiene, the presence or absence of solvent, the temperature of the reaction~ etc. Generally, a reaction period between about 5 ~' ' ~:
'''':~' , ' , `' ' . ' and 100 hours will sufflce, but preferably from about 10 to 48 hours.
The reaction is preferably and conveniently carried out under atmospheric pressure conditions although superatmospheric pressures may be used, and on occa~ion may be preferred, especially when one of the reactants is of low reactivity and/or high vola~ility.
Generally, when superatmospheric pressure is used, autogeneous pressure wili suffice although pressures of from 1.1 atmospheres to 100 atmospheres or mor can be used.
Following cGmpletion of the adduction step, the solvent, if present~ may be removed, e.g.~ by distillation and the adduct product purified, e.g., by distillation, recrystallization or both~
Alternatively, the crude adduct can be halogenated directly, before or after removal of the solvent, if present. However, if the solvent (for example, toluene) used in the adduction step is reactive to j 15 halogen, it should be removed prior to halogenation of the adduct.
^ Furthermore, if the solvent for the adduction of the halocyclo-pentadiene and n¢rbornadiene is an excess of the latter, it should be removed prior to bromination since it has been reported that, upon reaction with bromine~ it produces toxic materials. (J.A.C.S. 83, 1516 (1961)) The second, or halogenation step of the process is preferably a liquid phase reaction, also. The temperature employed ranges from about -20 to about 150 degrees Celsius. Preferably, the reaction temperature is within the range of about -10 degrees to about 100 degrees Celsius. The time required may vary considerably and according to the degree of halogenation desired. Generally, from a few minutes to about twenty-four hours will be required although this period may vary, according to the temperature of the reaction, the rate at which the halogeDating agent is fed into the reaction solution, the quantity of reactant, the presence, type and quantity of catalyst, reactivity of the substrate and the like variables.
- The solvent used in this step should be one that is inert to the reactants and the reaction product. Typical of the solvents ., ~ .
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~h;cll may be used include chlorlnated aliphatics of from I to 6 carbon atoms, such as carbon tetrachloride, chloroform, and the like.
When the adduction reactants are a halocyclopentadiene and norbornadiene the resultant adduct is halogenated by an addltion reaction employTng halogenatlon reagents such as chlorine, bromine or mixtures thereof such as bromlne chlorlde. This may occur via an - ionic or free radical mechanlsm. Subsequent to the halogen addition to the adduct of a halocyclopentadlene and norbornadlene, further halogenation may be accomplished vla a free radical substitution pathway d;scussed Tn the followlng paragraph, which relates to free ~- radical halogen substitution of the adduct of norbornene and a halo-cyclopentadiene.
When the adductlon reactants are a halocyclopentadiene and ; norbornene, the resultant adduct is halogenated by a substitution ~! 15 reaction employing a free rad;cal halogen substituting agent. free - radical halogenatlng agents whlch can be used in this process are . . , ~, known. Among the free radical chlorinatlng agents which can be used, ''1 ' .
I the following are typical examples: chlorlne; t-butyl hypochlorite;

sulfuryl chloride; chlorlne monoxide; trichloromethanesulfonyl chloride;
.
,~r 20 trichloromethanesulfenyl chloride; N-chlorosucclnimlde; phosphorus .~
pentachloride; iodobenzene dlchlorlde; cupric chlorlde; N-chloro-sulfonamide; N-chloro-dlmethylamine-sulfuric acid-acetlc acid-ferrous sulfate.
.,r As examplary of the free radlcal bromlnatlon agents whlch ~' 2~ are useful in thls process the follow7ng are mentioned: bromine;
Il-bromosuccinimide; sulfuryl bromide; bromotrichloromethane; t-butyl-I
~ hypobromite; trichloromethanesulfonylbromide; bromtne-chlorine mixtures.
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By the term "free radical halogen substituting agent" Is meant any halogenating agent capable of effecting halogen substitution - 30 under free radical condittons. A dtscussTon of this type of halo-genation reaction is contalned in "Free Radical Chemistry" E. S. Hyser, ,'' , ~ .

~ditor, published by Marcel Dekker, New York, 1969, particularly, for chlorination, sce Vol. I, Chapter 3, by M. L. Poutsma, and, for bromination, sec Vol. Il, Chapter 2, by W. A. Thaler.
The preferred free radical halogen substltuting agents are chlorine, bromine, sulfuryl cl1loride, sulfuryl bromide and mixtures thereof, because of their general effectiveness, availability and relative low cost.
In the case of suhstttution reactions, mtxtures of bromine and chlorine can be used to brominate organic compounds to conserve the amount of the rclattvely expensivc bromine. Ha10genated products produced using mixtures of bromine and chlorine, while predomlnently brominated derivatives invarlably also contain some proportions of the mixed halogenated derivatlves, that is the products contain bromine and chlorine substttuents.

The amount of halogenation agent employed is dependent on the amount of halogen deslred in the final compound. In general, a molar ratio of from about I to about 15 moles of halogenation agent per mole -~ of adduct 7s satisfactory.
:.
A, The reactlon product of the halogenation step may be a mlxture of halogenated compounds having an average of between about 2 and 6 halogen atoms on tl-e norbornene moiety of the adduct. Such a mlxed reactlon product may be separated from the solvent, for example, by a slmple distillation of the solvent. The resultant mtxture of halogenated adduct, having an average halogen content in accordance with the above formulae, may be employed directly as a fire retardant wlthout further purlfication.
Alternately, the mixture may be separated into its component compounds by known separation methods such as vacuum distTllatlon, fractional crystal-Iization and the lt~e, and the separated compounds having between about

2 and 6 halogen atoms on the norbornene molety may be used as fire retardant additives.

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, -106Z;~84 In either the substitution or addition type reaction, the halogenated step can be effected in the presence of a catalytic ;~ proportion of a halogenated catalyst. Typical of the catalysts ~- suitable for use in this step include sunlight; incandescent light;
ultraviolet light; organic peroxides which decompose to free radicals under reaction conditions, such as benzoyl peroxides, lauryl peroxide, 2-ethyl-hexyl peroxydicarbonate, methyl ethyl keton peroxide; azo compounds, such as azo bis isobutyronitrile, 2,2' azo bis (2,4-dimethyl valero) nitrile. Preferably, a source of wave energy, e.g., sunlight, incandescent or ultraviolet light, is used to catalyze the halogenation of the adduct.
` The halogenated norbornene-polyhalocyclopentadiene adducts , disclosed above are useful as fire retardant additives for normally - flammable polymers, for example, thermoplastics, such as polyethylene, . . .
~ 15 polypropylene, polystyrene, high impact polystyrene, (a graft blend .. ..
of polystyrene and poly-butadiene interpolymer), nylon, polyesters polyacrylates, and graft copolymers of polybutadiene, styrene, and acrylonitrile (commonly called "ABS" resins); thermosets, such as :. :
phenolics, epoxies, unsaturated polyesters, amino-formaldehyde resins, and the like; elastomers or rubbers, such as polyurethanes or styrene-butadiene rubber (SBR) and the like. These compounds - can also be used to impart fire resistant properties to other :, ~` high molecular weight polymers, copolymers and resins, including, for example, those disclosed in U.S. Patent 3,403,036.
", ~ 25 The fire retardant additive compounds are desirably incorporated ,','' ., ~ .

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~. - , in the normally flammable polymerlc maeerials in an effective flre retardant amount. Generally, the compounds in the amount of from about 2 to about 50 percent by weight of the polymeric composltion and desirably from about 5 to about 40 percent by weight, preferably from about 10 to about 35 percent by welght of the polymerlc composition are mlxed into said composition. Improved fire retardance and other desirable character-istics can be provided by incorporatlng such other adjuvants as metallic compounds such as antimony, bismuth, tin, iron, zinc and arsenic compounds, ; e.y., antimony oxide, iron oxide, zinc oxide and arsenlc sulflde, generally in the amount of from about 1 to about 30 percent by welght and preferably from about 2 to 25 percent by welght of sald polymertc ~omposition.
~ther adjuvants such as plasticizers, mold release agents, lubricants, fillers, dyestuffs and pTgments, may be included also.
The compounds of the present invention, in thelr use as ftre ' 15 retardant additives, can be mlxed into the polymer by any of several well known methods. The addltTves can be introduced Tnto the polymer or , its precurser(s) while the latter is dlssolved tn a sultable-solvent.
This procedure is especially sultable when It is desired to incorporate ~. .
the additives during the polymer manufacturing process. When the polymer is subsequently recovered from the solvent, the additlves are Intlmately mixed wlth the polymer. The additlves may be mlxed wTth the polymer in the flnely dlvided state and the mlxture dry blended so that an intimate mlxture Is obtained on moldlng, mllllng, or extruslon. Alternatlvely, the additives may be mixed with the polymer in the molten state at temperatures ~, 25 whTch can range from the ~el~ing polnt to just below the decomposition temperature of the polymerlc composltion.
The followtng examples will illustrate the inventlon, but such examples are not intended to limit the scope of the invention. In the examples, as well as in the above specification and clalms appended hereto, parts and percentages are by weight and temperatures are given in degrees Celsius, unless otherwlse specified.

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EXAMPLE I
Preparation of the Mono-Adduct of Norbornene and Hexachlorocyclopentadiene A mixture of 312 parts of norbornene and B85.6 parts of hexachlorocyclopentadiene was heated under a reflux condenser. The mixture was heated from 124 to 150~ during a 90 minute period and maintalned at about 150 for about 18 hours thereafter. The mass was permitted to cool to amb1ent temperature. The resultant crude adduct was purified by distillation in vacuum. There was thus obtained 1041.7 parts of 1,2,3,4,10,10-hexachloro-1,4,4a,5,6,7,8,9a-octahydro-1,4:5,8-dimethanonaphthalene, boiling at 139 to 141 at 0.2 mm of mercury. The distillate solidified upon cooling.
EXAMPLE II
- Preparation of 1,2,3,4,6,6,7,7,10,10-Decachloro-'Jj 15 1,4,4a,5,6,7,8,8a-Octahydro-1,4:5,8-Dimethanonaphthalene An adduct of norbornene and hexachlorocyclopentadiene was ,.,j prepared as described in Example 1. A solution of 80 parts of this adduct in 640 parts of carbon tetrachloride was prepared. Chlorine gas (139 parts) was bubbled into the solution during a 4 hour period while the solution was irradiated with a mercury arc lamp (West~nghouse H5KA).
Thereafter the solvent was removed and 122.8 parts of white solid was obtained. This was recrystall~zed from hexane. The recrystallized product melted at 185.5 to 191.5. Nuclear magnetic resonance and elemental analysis of the product confirmed the compound was 1,2,3,4, . 25 6,6,7,7,10,10-decachloro-1,4,4a,5,6,7,8,8a-octahydro-1,4:5,8-dimethano-naphthalene.
EXAMPLE I I I
, Preparation of a Bromo-Chloro-Derivative of the I Mono-Adduct of Norbornene and Hexachlorocyclopentadiene :j . .
A solution of 72.3 parts of bromine and 29 parts of chlorine in 160 parts of carbon tetrachloride was added slowly over about 3.75 hours to a solution of 100.5 parts of 1,2,3,4,10,10-hexachloro-1,4,4a, .

~062284 5,6,7,8,8a-octahydro-1,4:5,8-dimethanonaphthalene dissolved in 640 parts of carbon tetrachloride while the latter solution was irradiated with a 200 watt incandescent lamp. After completion of the addition of the solution the reaction mixture was irradiated for about two additional hours and then permitted to stand without irradiation for about 16 hours. The solvent was stripped from the reaction mixture to yield 151.5 parts of light yellow oil which was determined by elemental analysis to be a mixture of bromo-chlorinated derivatives of the norbornene-hexachlorocyclopentadiene adduct hav;ng an average formula C12H7 5Brl 5C17.
EXAMPLE IV
A molding composition was prepared from 80 parts of high impact polystyrene (Dylene 957~), 5 parts of antimony oxide and 15 parts of the product of Example III. The molding compositions was tested for fire retardance according to the test method ASTM-D-635-72 and found to be self-extinguishing within 2 seconds with ; an afterglow of 11 seconds. The composition had an Oxygen Index of 26 when tested according to the test procedure ASTM-D-2863-70.
EXAMPLE V
.~, A molding composition was prepared from 80 parts of high impact polystyrene (Dylene 957~), 15 parts of the product of Example II, and 5 parts of antimony oxide. When tested according to a modified* ASTM-D-635-72 test procedure, the composition was ~, found to be self-extinguishing within 17 seconds with a 13 second afterglow. The composition was tested according to the test prscedure ASTM-D-2863-70 and found to have an Oxygen Index of 24Ø
* The test method ASTM-D-635-72 was modified in that a cylindrical specimen about 150 mm long and 8 mm in diameter was substituted for the usual 127 mm length x 12.7 mm width bar.

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The following example describes the preparation of a compound of the present invention, using as starting materials, hexachlorocyclo-pentadiene and norbornadiene:
EXAMPLE VI-A
Preparation of the Mono-Adduct of Norbornadiene and Hexachlorocyclopentadiene A solution of 273 parts of hexachlorocyclopentadiene and 92.2 parts of norbornadiene was added slowly, over a period of one hour to 276.4 parts of norbornadiene under reflux conditions in an atmosphere of nitrogen. The mixture was held at refluxing temperature (87 to 107) under an atmosphere of nitrogen for 97.5 hours. The excess of norborn-adiene was removed by distillation at atmospheric pressure. The remaining product was twice distilled to yield 285.3 parts of the mono-adduct.
Further purification was effected to recrystallization from ethanol and discolorization with carbon. The purified product, 1,2,3,4,10,10-hexa-chloro-1,4,4a,5,8,8a-hexahydro-1,4:5,8 dimethanonaphthalene melted at . 105 to 107.
EXAMPLE VI-B
Preparation of a Chloro- Derivative of the Mono-Adduct of Norbornadiene and Hexachlorocyclopentadiene A solution of 78 parts of the adduct of example VI-A in 640 parts of carbon tetrachloride was prepared. The solution was irradiated with a 200 watt mercury arc lamp while 139 parts of chlorine was bubbled in over a 4-hour period. The reaction temperature was maintained at 50C.
, The reaction mixture was stirred for an additional hour. Thereafter, the solvent was removed by distillation at reduced pressure to yield 118.8 parts of a white solid. The solid recrystallized twice from he~ane.
The recrystallized product melted at 191 to 193C. Nuclear magnetic resonance analysis confirmed the compound as 1,2,3,4,6,6,7,7,10,10-decachloro-1,4,4a,5,6,7,8,8a-octahydro-1,4:5,8-dimethanonaphthalene.
Additional disclosure of the utility of the compounds of the present invention is set forth in Canadian application SN 221,052, filed February 24, 1975 James J. Maul et al.

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10~;2284 It ~i11 be a~parPnt to those ski11cd in the art that many variations and modifications of the 1nvention as set forth hereinabove may be made without departing from the spirit and scope of the invention.
: The invention is not to be construed as 1imited to the description and s examples set forth hereinabove.
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Claims (2)

1. THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
   OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
   
   A compound of the formula wherein n has an average value of from 0 to 6, m has an average value of from 0 to 6, the total of n plus m is from about 2 to 6, with the proviso that when the total of n plus m is about 2, n is about 1 and m is about 1.
   
   A compound according to Claim 1, wherein n has an average value of from 0 to about 2, m has an average value of from 0 to about 4 and the total of m plus n is from about
2. 2 to 4.
   
   A compound according to Claim 1, wherein n has an average value of about 1.5 and m has an average value of about 1.
   
   A compound according to Claim 1, wherein n is 0 and m is 4.
   
   A mixture consisting essentially of compounds according to Claim 1.