# US 9,434,674 B2 · Latent heat storage using renewable phase change materials > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,434,674 B2 - Document ID: US9434674B2 - Status: Granted - Kind: B2 - Application number: 14/605,344 - Filed: 2015-01-26 - Published: 2016-07-28 - Granted: 2016-09-06 - Earliest claimed: 2015-01-26 - Assignees: Trent University - Applicants: Trent University - Inventors: Suresh S. Narine; Michael C. Floros - Web page: https://patentgrep.com/patent/US9434674B2 ## CPC - C07C 67/03: by reacting an ester group with a hydroxy group - C07C 67/52: by change in the physical state, e.g. crystallisation - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS ## Abstract A method of producing a diol diester, which includes reacting a fatty acid alkyl ester having 6 to 30 carbon atoms, an α,ω-alkanediol having n carbon atoms, wherein n is an integer from 2 to 22; and a basic transesterification catalyst, is provided. Use of the diol diesters as phase change materials is also provided. ## Claims ### Claim 1 A method of producing a diol diester comprising reacting: a fatty acid alkyl ester having 6 to 30 carbon atoms; an α,ω-alkanediol having n carbon atoms, wherein n is an integer from 2 to 22; and about 0.01 to 1.0 wt. % (based on the weight of the mixture) of a basic transesterification catalyst; wherein the mixture is reacted at a reaction temperature of at least about 60° C. to provide a first reaction product comprising the diol diester; and the method further comprises recrystallizing the idol diester produced by the reaction. ### Claim 2 (depends on 1) The method of claim 1 further comprising diluting the first reaction product with an organic solvent to provide a diluted reaction product; and filtering the diluted reaction product to remove the basic transesterification catalyst. ### Claim 3 (depends on 1) The method of claim 1 further comprising dissolving the diol diester in the first diol diester product in an organic solvent to provide a dissolved product mixture; and filtering the dissolved product mixture. ### Claim 4 (depends on 3) The method of claim 3 wherein filtering the dissolved product mixture comprises filtering the dissolved product mixture slurried with a filtering aid. ### Claim 5 (depends on 1) The method of claim 1 wherein reacting the mixture produces an alkanol and the method further comprises continuously removing the alkanol from the reacting mixture. ### Claim 6 (depends on 1) The method of claim 1 wherein the mixture includes the fatty acid alkyl ester and the α,ω-alkanediol in a mole ratio of about 2:1 to 5:1. ### Claim 7 (depends on 1) The method of claim 1 wherein the mixture is substantially free of solvent. ### Claim 8 (depends on 1) The method of claim 1 wherein the basic transesterification catalyst is an inorganic basic compound. ### Claim 9 (depends on 1) The method of claim 1 wherein the basic transesterification catalyst is an alkali metal hydroxide, an alkali metal alkoxide and/or alkali metal carbonate. ### Claim 10 (depends on 1) The method of claim 1 wherein the fatty acid alkyl ester is a fatty acid methyl ester having 7 to 23 carbon atoms; the α,ω-alkanediol has 2 to 22 carbon atoms; and the basic transesterification catalyst comprises an alkali metal hydroxide and/or alkali metal carbonate. ### Claim 11 (depends on 1) The method of claim 1 wherein the basic transesterification catalyst is potassium hydroxide. ### Claim 12 (depends on 1) The method of claim 1 wherein the basic transesterification catalyst is potassium carbonate. ### Claim 13 (depends on 1) The method of claim 1 wherein the fatty acid alkyl ester is a fatty acid methyl ester; and the method further comprises removing methanol from the reacting mixture. ### Claim 14 (depends on 13) The method of claim 13 comprising removing the methanol from the reaction mixture under vacuum. ### Claim 15 (depends on 1) The method of claim 1 wherein the fatty acid alkyl ester is a fatty acid methyl ester; and the method comprises reacting the mixture at a temperature of about 90° C. to 150° C. ### Claim 16 (depends on 1) The method of claim 1 wherein the fatty acid alkyl ester is a methyl ester of a fatty acid having an even number of carbon atoms. ### Claim 17 (depends on 1) The method of claim 1 wherein the fatty acid alkyl ester comprises one or more saturated fatty acid methyl esters. ### Claim 18 (depends on 1) The method of claim 1 wherein the fatty acid alkyl ester comprises one or more unsaturated fatty acid methyl esters. ### Claim 19 (depends on 1) The method of claim 1 wherein the α,ω-alkanediol is ethanediol; 1,3-propanediol and/or 1,4-butanediol. ### Claim 20 A method of producing a diol diester comprising reacting: a fatty acid alkyl ester having 6 to 30 carbon atoms; wherein the fatty acid alkyl ester comprises one or more unsaturated fatty acid methyl esters; an α,ω-alkanediol having n carbon atoms, wherein n is an integer from 2 to 22; and about 0.01 to 1.0 wt.% (based on the weight of the mixture) of a basic transesterification catalyst; wherein the mixture is reaction temperature of at least about 60° C. to provide a first reaction product comprising the diol diester; and the method further comprises hydrogenating the first reaction product. ### Claim 21 A method of producing a diol diester consisting essentially of reacting: an aliphatic carboxylic acid alkyl ester having 6 to 30 carbon atoms, an α,ω-alkanediol having n carbon atoms, wherein n is an integer from 2 to 22, and about 0.01 to 1.0 wt.% (based on the total weight of the starting mixture) of a basic transesterification catalyst; wherein the reaction is conducted at a reaction temperature of at least about 60° C. to provide a first reaction product comprising the diol diester while substantially removing alkanol from the reacted mixture via distillation; and (c) diluting the reacted mixture with a solvent to form a product solution; (d) filtering the product solution to remove the basic transesterification catalyst and provide a filtered solution; and (e) recrystallizing the diol diester from the filtered solution to provide a recrystallized diol diester. ### Claim 22 (depends on 21) The method of claim 21 wherein filtering the product solution comprises filtering the product solution slurried with a filtering aid. ### Claim 23 (depends on 21) The method of claim 21 wherein the recrystallized diol diester does not exhibit a thermal degradation peak below 300° C. as determined by derivative thermogravimetric analysis. ### Claim 24 (depends on 21) The method of claim 21 wherein the recrystallized diol diester has a peak melting point of at least about 60° C. ### Claim 25 (depends on 21) The method of claim 21 wherein the recrystallized diol diester has a peak melting point of at least about 60° C. and a latent heat enthalpy of at least about 225 kJ/kg and does not exhibit a thermal degradation peak below 300° C. as determined by derivative thermogravimetric analysis. ### Claim 26 (depends on 25) The method of claim 25 wherein the aliphatic carboxylic acid alkyl ester is a methyl ester of a fatty acid having 16 and/or 18 carbon atoms; and the α,ω-alkanediol has 5, 7 or 9 carbon atoms.