# US 9,518,030 B2 · Purification of aryltriazoles > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,030 B2 - Document ID: US9518030B2 - Status: Granted - Kind: B2 - Application number: 14/954,345 - Filed: 2015-11-30 - Published: 2016-03-31 - Granted: 2016-12-13 - Earliest claimed: 2013-07-01 - Applicants: Randolph K Belter - Inventors: Randolph K Belter - Web page: https://patentgrep.com/patent/US9518030B2 ## CPC - C07D 249/18: Benzotriazoles - C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08) ## Abstract Impure aryltriazoles such as benzotriazole and tolyltriazole that are contaminated with dark colored impurities can be purified by conversion to an aryltriazole acid salt by treatment with aqueous acid. The aryltriazole acid salt is water soluble whereas the dark colored impurities are not. The aryltriazole acid salt solution is separated from the dark colored impurities and the aryltriazole acid salt is isolated by precipitation. The free aryltriazole may be recovered by neutralization with base. ## Claims ### Claim 1 A process for purifying an impure aryltriazole obtained by the diazotization reaction of an ortho-phenylenediamine with a nitrite, said impure aryltriazole containing dark and colored impurities, consisting of the steps: 1) dissolving at a temperature of 50 to 100° C. said impure aryltriazole with an aqueous solution of at least 1 equivalent of a 10-20% aqueous solution of strong acid to form two liquid phases, one phase of said two liquid phases comprising the cationic form of said aryltriazole in an aqueous solution and other phase of said two liquid phases comprising substantially all of the dark and colored impurities; 2) separating the one phase of the said two liquid phases comprising said cationic form of said aryltriazole in an aqueous solution from the other phase of the liquid mixture comprising substantially all of the dark and colored impurities; 3) cooling said one phase of the said two liquid phases comprising said cationic form of said aryltriazole in an aqueous solution to less than 50° C., thereby forming two new phases, one phase being the solid cationic form of said aryltriazole and the other phase being an aqueous solution; 4) separating said solid cationic form of said aryltriazole from said aqueous solution. ### Claim 2 (depends on 1) The process according to claim 1 wherein the impure aryltriazole is benzotriazole. ### Claim 3 (depends on 1) The process according to claim 1 wherein the impure aryltriazole is tolyltriazole. ### Claim 4 (depends on 1) The process according to claim 1 wherein the strong acid is selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and perchloric acid. ### Claim 5 (depends on 1) The process according to claim 1 wherein the strong acid is sulfuric acid. ### Claim 6 (depends on 1) The process according to claim 1 wherein the strong acid is selected from the group consisting of phosphoric acid and nitric acid. ### Claim 7 (depends on 1) The process according to claim 1 wherein said dissolving is carried out using at least 1 equivalent of strong acid per mole of aryltriazole. ### Claim 8 (depends on 1) The process according to claim 1 wherein said dissolving is carried out using at least 0.5 moles (1 equivalent) of sulfuric acid per mole of aryltriazole. ### Claim 9 (depends on 1) The process according to claim 1 wherein said dissolving is carried out using at least 1.0 moles (1 equivalent) of strong acid selected from the group consisting of hydrochloric and nitric acid per mole of aryltriazole. ### Claim 10 (depends on 1) The process according to claim 1, step 2 wherein said separating is carried out at a temperature of from about 50 degrees centigrade to about 100 degrees centigrade (Celsius). ### Claim 11 (depends on 1) The process according to claim 1, step 2 wherein said separating is carried out at a temperature of from about 80 degrees centigrade to about 100 degrees centigrade (Celsius). ### Claim 12 (depends on 1) The process according to claim 1 wherein said solid cationic form of said aryltriazole is treated with an aqueous solution of base to form an aqueous solution containing the anionic form of said aryltriazole. ### Claim 13 (depends on 1) The process according to claim 1, wherein said aqueous solution of step 4 is recycled to form a recycle liquid, forming a solution of an impure aryltriazole with 10-20% aqueous solution of a strong acid using said recycle liquid as the solvent, to form two liquid phases, one phase of said two liquid phases comprising the cationic form of said aryltriazole and the other phase of said two liquid phases comprising substantially all of the dark and colored impurities, and repeating steps 2, 3 and 4. ### Claim 14 (depends on 1) The process according to claim 1 wherein said aqueous solution from Step 4 is purified by treating the solution with an adsorbing media selected from the group consisting of activated carbon, kieselguhr, diatomaceous earth, clays, alumina, fuller's earth, pumice, sodium dithionite, and “oil only” absorbents thereby forming a purified residual aqueous phase. ### Claim 15 (depends on 1) The process according to claim 1 wherein the aqueous solution of the cationic form of said aryltriazole of Step 2 is treated with an adsorbing media selected from the group consisting of activated carbon, kieselguhr, diatomaceous earth, clays, alumina, fuller's earth, pumice, sodium dithionite and “oil only” absorbents thereby forming a further purified aqueous aryltriazole salt solution. ### Claim 16 (depends on 1) The process according to claim 1 wherein the aqueous solution of the cationic form of said aryltriazole acid salt solution of Step 2 is treated with an adsorbing media consisting of “oil only” absorbents. ### Claim 17 A process for purifying impure tolyltriazole obtained by the diazotization reaction of an ortho-toluenediamine with a nitrite, said impure tolyltriazole containing dark and colored impurities, consisting of the steps: 1) dissolving at a temperature of 80 to 100° C. said impure tolyltriazole with an aqueous solution of at least 1 equivalent of a 10-20% aqueous solution of sulfuric acid to form two liquid phases, one phase of said two liquid phases comprising the cationic form of tolyltriazole in an aqueous solution and the other phase of said two liquid phases comprising substantially all of the dark and colored impurities; 2) separating the one phase of the said two liquid phases comprising said cationic form of tolyltriazole in an aqueous solution from the other phase of the liquid mixture comprising substantially all of the dark and colored impurities; 3) cooling said one phase of the said two liquid phases comprising said cationic form of tolyltriazole in an aqueous solution to less than 50° C., thereby forming two new phases, one phase being the solid cationic form of said tolyltriazole and the other phase being an aqueous solution; 4) separating said solid cationic form of said tolyltriazole from said aqueous solution.