Patent ID: 8309760

Claim:
A process for providing crystalline terephthalic acid comprising: a) providing a composition comprising 5% to 99% by weight of terephthalic acid and one or more ionic liquids, wherein the ionic liquids comprise: a) a cation formed from an alkylated heterocyclic or heteroaryl unit chosen from imidazole, pyrazole, thiazole, isothiazole, azathiozole, oxothiazole, oxazine, oxazoline, oxazaborole, dithiozole, triazole, selenozole, oxahosphole, pyrrole, borole, furan, thiophene, phosphole, pentazole, indole, indoline, oxazole, isothirazole, tetrazole, benzofuran, dibenzofuran, benzothiophene, dibenzothoiphene, thiadiazole, pyrdine, pyrimidine, pyrazine, pyridazine, piperazine, piperidine, morpholine, pyran, annoline, phthalazine, quinazoline, and quinoxaline; and b) an anion chosen from: i) F − − , Cl − , Br − , and I − ; ii) BX 4 − ; PX 6 − ; AsX 6 − ; and SbX 6 − ; wherein X − is a halogen chosen from F − , Cl − , Br − , and I − ; iii) NO 2 − ; iv) NO 3 − ; v) SO 4 2− ; vi) (CF 3 )SO 3 − ; vii) substituted or unsubstituted)B(R 10 ) 4 − ; viii) substituted or unsubstituted (R 10 O)S(═O) 2 O − ; ix) substituted or unsubstituted (R 10 O) 2 PO − ; x) substituted or unsubstituted R 10 CO 2 − ; xi) substituted or unsubstituted (R 10 O) 2 P(═O)O − ; xii) substituted or unsubstituted (R 10 O)C(═O)O − ; xiii) substituted of unsubstituted azolate; R 10 is independently hydrogen; substituted or unsubstituted linear; branched, and cyclic alkyl; substituted or unsubstituted linear, branched, and cyclic alkoxy; substituted or unsubstituted aryl; substituted or unsubstituted aryloxy; substituted or unsubstituted heterocyclic; substituted or unsubstituted heteroaryl; acyl; silyl; boryl; phosphino; amino; thio; and seleno; or wherein the azolate can be substituted on a carbon atom by a unit chosen from cyano, nitro, and amino; and b) combining the composition of step (a) with a non-solvent, thereby crystallizing terephthalic acid.