the process of the invention is directed to the preparation of compounds of formula i : ## str1 ## wherein r is lower alkyl of from one to six carbons such as methyl , ethyl , n - propyl , n - hexyl and the like . these compounds are prepared by heating a compound of formula ii : ## str2 ## wherein r is the same as set forth hereinabove and x is br , cl or i in the presence of a solvent and a catalyst that comprises a nickel compound and a reducing compound . suitable solvents for the practice of the invention include saturated aliphatic hydrocarbons and aromatic hydrocarbons such as hexane , pentane , benzene , xylene , etc ; ethers such as diethyl ether , tetrahydrofuran etc ; dimethylacetamide ; dimethyl sulfoxide , dimethylformamide ; and the like . the useful nickel compounds include complexes of nickel and organometallic nickel compounds . these compounds include nickel halides such as nickel chloride , nickel iodide and nickel bromide ; nickel sulfate , nickel carbonate , nickel phosphates and the like . nickel salts of aliphatic organic acids having from 1 - 20 carbon atoms such as nickel formate , nickel acetate , nickel stearate ; nickel complexes such as nickel acetoacetonate and the like . the amount of nickel that is used is from about 0 . 005 to about 1 . 0 and preferably from about 0 . 01 to about 0 . 5 moles of nickel per mole of compound of formula ii . an inorganic salt such as an alkali metal bromide may be added to the reaction mixture in an amount of 0 . 01 - 500 moles per gram atom of catalyst . the useful triarylphosphines include triphenylphosphines . the ratio of triarylphosphine to nickel may be from about 0 . 01 to about 25 , and preferably from 1 to 10 moles of triaryl phosphine per mole of nickel . the reducing metal may be manganese , magnesium or zinc . these reducing metals may be used in a finely divided form at a ratio of 0 . 5 moles to 1 . 5 moles per mole of the compound of formula ii . zinc is the preferred reducing metal . the compounds of formula i may be used to make homopolymers or copolymers if they are first converted to a tetraacid of formula iii . ## str3 ## which may be dehydrated to the anhydride of formula iv : ## str4 ## the homopolymers or copolymers are prepared by reaction with a diamine of formula v . wherein r 1 is a divalent organic radical selected from the class consisting of ( a ) aromatic hydrocarbon radicals having from 6 - 20 carbon atoms and halogenated derivatives thereof , ( b ) alkylene radicals and cycloalkylene radicals having from 2 - 20 carbon atoms . c . sub . ( 2 - 8 ) alkylene terminated polydiorganosiloxane , and ( c ) divalent radicals included by the formula ## str5 ## where q is a member selected from the class consisting of -- o --. ## str6 ## and x is a whole number from 1 to 5 inclusive . in addition , copolymers may be prepared by utilizing from 10 - 90 mole % of an anhydride of formula iv with 90 - 10 mole % of a dianhydride of formula vi and a diamine of formula v : ## str7 ## wherein e is selected from phenylene , biphenylene , naphthylene , alkylene or alkylidene . useful alkylene groups include methylene , ethylene and the like ; alkylidene groups include ethylidene and isopropylidene . the preferred group for b is isopropylidene . the copolymers may be prepared by combining the diamine of formula v with the dianhydrides of formula iv and formula vi in a suitable reactor in the presence of a suitable solvent . the reaction is carried out by heating the reactants in an inert atmosphere such as nitrogen using a suitable means of agitation such as a mechanical stirrer . the water formed by the polymer formation is removed by azeotropic distillation and the polymer may be recovered by precipitation with an antisolvent such as methanol . the copolymers have repeating units of the formula : ## str8 ## wherein r 1 is as defined above ; and a represents from 10 to 100 units ; and ## str9 ## wherein e is selected from the group consisting of phenylene , biphenylene , naphthylene , alkylene or alkylidene and b is from 10 to 100 and r 1 is as defined above . these polymers are thermoplastic and may be molded to form useful articles having a high heat distortion temperature . they may be combined with reinforcing fillers and other fillers such as from 1 - 50 % by weight of fibrous glass , wollastonite , clay , talc , mica , carbon fibers , aramid fibers , calcium carbonate and the like . if desired , flame retardant amounts of flame retardant agents such as those described in u . s . pat . no . 4 , 020 , 124 , which is incorporated by reference , may be added . the following examples illustrate the process of the invention . they are merely illustrative and are not to be construed to limit the invention in any manner whatsoever . in a 500 ml three - necked flask equipped with a mechanical stirrer , dean - stark trap / condenser , nitrogen inlet , and thermometer was added 25 . 71 grams ( 0 . 20 moles ) of p - chlorophenol , 100 ml dimethylsulfoxide , and 150 ml of chlorobenzene . after stirring and nitrogen purging the mixture for 30 min ., 15 . 80 grams of aqueous sodium hydroxide ( 50 . 62 wt . %; 0 . 20 moles ) was added . the mixture was heated up to 150 ° c . with the azeotropic removal of the water of reaction . after the removal of water was complete the temperature was lowered to 60 ° c . and 41 . 23 grams ( 0 . 20 moles ) of 4 - nitro - n - methyl phthalimide was added . the mixture was stirred overnight . upon cooling to room temperature the product precipitated from solution . filtration , washing the precipitate with water , and recrystallization from isopropanol yielded 50 . 8 grams of 4 -( p - chlorophenyl )- n - methyl phthalimide . the melting point was 131 °- 132 ° c . to a dry 250 ml . flask equipped with a magnetic stirring bar and nitrogen inlet were added 0 . 65 grams ( 0 . 00502 moles ) nickel chloride , 5 . 00 grams ( 0 . 01906 moles ) triphenyl phosphine , 5 . 00 grams ( 0 . 0486 moles ) sodium bromide , 7 . 51 grams ( 0 . 115 moles ) zinc dust , and 2 . 88 grams ( 0 . 010 moles ) 4 -( p - chlorophenol )- n - methyl phthalimide . after purging with nitrogen for 60 minutes , 75 ml of dry dimethylacetamide was added and the mixture was heated to 70 ° c . with stirring . after three hours the mixture was cooled , poured into water and filtered . this crude material was purified and separated from the inorganics by dissolving in hot chlorobenzene and filtering . upon cooling , the product precipitated from solution . filtration and drying ( 80 ° c . overnight ) yielded 2 . 1 grams of bisimide . mp 201 °- 203 ° c . to a dry 250 ml flask equipped with a magnetic stirring bar and nitrogen inlet were added 0 . 65 grams ( 0 . 00502 moles ) nickel chloride , 3 . 75 grams ( 0 . 01906 moles ) triphenyl phosphine , 5 . 00 grams ( 0 . 486 moles ) sodium bromide , 0 . 75 grams ( 0 . 0048 moles ) dipyridyl , 7 . 51 grams ( 0 . 115 moles ) zinc dust , and 25 . 0 grams ( 0 . 0869 moles ) 4 -( p - chlorophenol )- n - methyl phthalimide . this mixture was purged with nitrogen for 60 minutes and 75 ml of dry dimethylacetamide was added . the mixture was heated slowly to 70 ° c . after 5 hours the mixture was cooled , poured into water and filtered . the crude material was purified and separated from inorganics via dissolving in chlorobenzene and filtration . upon cooling the product precipitated from solution . filtration and drying overnight at 80 ° c . gave the bisimide ; mp . 204 °- 205 ° c . the bisimides prepared in examples i and ii were converted to the corresponding dianhydride according to the following procedure . in a 50 ml flask equipped with a reflux condenser and magnetic stirrer is added 3 . 2 grams of bisphenol bisimide , 3 . 0 grams of 50 % aqueous sodium hydroxide , and 10 ml water . the mixture was heated at reflux with 18 hours , cooled to room temperature and acidified with an excess of 1n hydrochloric acid . the precipitated tetra acid was isolated by filtration , washed , and dried . in a 50 ml flask equipped with a condenser thermometer and magnetic stirrer was charged 3 . 2 grams of tetra acid , 4 . 0 ml acetic anhydride , and 8 . 0 ml o - dichlorobenzene . the mixture was heated to 135 ° c . after 18 hours the solution was cooled . the dianhydride precipitates as a finely divided solid and is collected by filtration and washed with chilled hexane . the product was dried in vacuo at 60 ° c . overnight . in a 100 ml flask equipped with dean stark trap / condenser , mechanical stirrer , nitrogen inlet and thermometer was added 2 . 90 g ( 0 . 00606 moles ) of the aforesaid dianhydride , 3 . 15 g ( 0 . 00605 moles ) of bpa dianhydride ( i . e . 2 , 2 bis ( 2 , 3 - dicarboxyphenoxy phenyl ) propane dianhydride ), 1 . 31 g ( 0 . 121 moles ) m - phenylene diamine , 0 . 03 g ( 0 . 00203 moles ) phthalic anhydride , 35 ml m - cresol , 25 ml toluene . the mixture was heated under nitrogen at 100 ° c . for 30 minutes , followed by raising the temperature to 150 ° c . in which the water formed in the reaction was removed by azeotropic distillation . after about 4 hours the temperature was increased to 180 ° c . and held there for one hour , then cooled to room temperature . the viscous mixture was diluted with 100 ml of chloroform and the polymer isolated by precipitation in methanol . the precipitate was dried at 125 ° c . to give 6 . 6 grams of polyetherimide copolymer . the polymer exhibited an intrinsic viscosity of 0 . 56 dl / gram when measured in phenol / tetrachloroethane ( 60 / 40 ; w / w ), at 30 ° c . and a glass transition temperature of 230 ° c . obviously other modifications and variations of the present invention are possible in the light of the above teachings . it is , therefore , to be understood that changes may be made in the particular embodiments of the invention described which are within the full intended scope of the invention as defined by the appended claims .