# US 10,308,674 B2 · Process for preparing high-purity L-arabinose by using arabic gum as raw material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,308,674 B2 - Document ID: US10308674B2 - Status: Granted - Kind: B2 - Application number: 15/550,655 - Filed: 2015-05-07 - Published: 2018-02-01 - Granted: 2019-06-04 - Earliest claimed: 2015-03-24 - Assignees: Zhejiang University - Applicants: Zhejiang University - Inventors: Zongbi Bao; Minhui Huang; Zhiguo Zhang; Qiwei Yang; Baogen Su; Huabin Xing; Qilong Ren; Yiwen Yang - Web page: https://patentgrep.com/patent/US10308674B2 ## CPC - C07H 3/02: Monosaccharides - C07H 1/08: from natural products - C07H: SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS (derivatives of aldonic or saccharic acids C07C, C07D; aldonic acids, saccharic acids C07C59/105, C07C59/285; cyanohydrins C07C255/16; glycals C07D; compounds of unknown constitution C07G; polysaccharides, derivatives thereof C08B; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; sugar industry C13) ## Abstract The present invention discloses a process for preparing L-arabinose from Gum Arabic comprising the steps of catalytical hydrolysis of L-arabinose from gum arabic followed by the purification steps including neutralization using alkali, adsorption bleaching, electrodialysis desalination, adsorption separation of impurities and crystallization, with the absolute purity of L-arabinose up to 98% and the recovery as high as 25%˜29% of material weight. The disclosed process has such advantages as low cost, environmental-friendliness and simple operation, showing promising in industrial production. ## Claims ### Claim 1 A process for preparing high-purity L-arabinose from gum arabic, the process comprising the following steps: (1) adding dissolved gum arabic into an inorganic acid to form a mixed solution, controlling pH value of the solution at 0.2˜1, undertaking hydrolysis reaction at the temperature of 70˜100° C., after the reaction, neutralizing the hydrolysate by adding an alkali aqueous solution to reach pH of about 4˜7 and obtaining the neutralized hydrolysate containing L-arabinose; (2) adding the hydrolysate of step (1) to a fixed bed equipped with an adsorbent A continuously, collecting an effluent that passes through the adsorbent A to form a decolored solution; (3) passing the decolored solution of step (2) through a microporous membrane of a drainage to obtain a pretreatment solution, then desalinating the pretreatment solution by electrodialysis to obtain a desalination solution; (4) passing the desalination solution of step (3) through a fixed bed equipped with an adsorbent B continuously under room temperature, collecting an effluent that passes through the adsorbent B, obtaining a supersaturated syrup by concentrating the effluent that passes through the adsorbent B under reduced pressure at 45˜60° C.; and (5) crystallizing the supersaturated syrup and obtaining white powder of L-arabinose after drying; wherein the adsorbent A is one of granular activated carbon, non-polar macroporous polystyrene adsorption resin, weak polar macroporous polystyrene adsorption resin, non-polar macroporous acrylic adsorption resin, weak polar macroporous acrylic adsorption resin, non-polar gel-type polystyrene adsorption resin, weak polar gel-type polystyrene adsorption resin, weak polar gel-type polystyrene acid adsorption resin, non-polar gel-type acrylic adsorption resin and weak polar gel-type acrylic adsorption resin; wherein the process of the electrodialysis consists of the steps of: circulating the pretreatment solution in concentrated solution chamber and pure water in diluted solution chamber of an electrodialysis instrument respectively through electrode chamber that contains Na2SO4 as polar water and desalinating for 2˜5 hours under constant voltage and velocity; wherein the adsorbent B is one of non-polar macroporous polystyrene adsorption resin, non-polar macroporous acrylic adsorption resin, non-polar gel-type polystyrene acid adsorption resin, non-polar gel-type acrylic adsorption resin, granular activated carbon, and silica gel bonded with C18 or C30; and wherein the process of the crystallization comprises the steps of: dissolving the supersaturated syrup of step (4) in alcohol, cooling the temperature to ambient temperature, inducing crystallization by adding some L-arabinose, filtering after crystallizing for 24˜72 hours, and obtaining pure L-arabinose with purity of 98% or higher after drying in a vacuum oven at 50˜60° C.; the alcohol is methanol or ethanol, the ratio of alcohol volume to the supersaturated syrup by weight is (6˜10) L: 1 kg, the cooling rate is 0.2˜3° C./min and crystallization temperature range is −5˜10° C. ### Claim 2 (depends on 1) The process for preparing high-purity L-arabinose from gum arabic according to claim 1, wherein the inorganic acid is sulfuric acid, hydrochloric acid, phosphoric acid or mixture of two thereof and molar concentration of H+is 1˜6 mol/L. ### Claim 3 (depends on 1) The process for preparing high-purity L-arabinose from gum arabic according to claim 1, wherein the hydrolysis time is 1˜5 hours. ### Claim 4 (depends on 1) The process for preparing high-purity L-arabinose from gum arabic according to claim 1, wherein decolorization temperature of step (2) is 20˜55° C. and flow rate is 0.5˜3 bed volume/hour. ### Claim 5 (depends on 1) The process for preparing high-purity L-arabinose from gum arabic according to claim 1, wherein the mass concentration of Na2SO4 is 3% ˜8% and the volume ratio of the pretreatment solution and pure water is 1: 1˜3. ### Claim 6 (depends on 1) The process for preparing high-purity L-arabinose from gum arabic according to claim 1, wherein the desalination conditions are as follows: operating voltage is 20˜30 V and the solutions flow rate is 10˜30 L/hours. ### Claim 7 A process for preparing high-purity L-arabinose from gum arabic, the process comprising the following steps: (1) adding dissolved gum arabic into an inorganic acid to form a mixed solution, controlling pH value of the solution at 0.2˜1, undertaking hydrolysis reaction at the temperature of 70˜100° C., after the reaction, neutralizing the hydrolysate by adding an alkali aqueous solution to reach pH of about 4˜7 and obtaining the neutralized hydrolysate containing L-arabinose; (2) adding the hydrolysate of step (1) to a fixed bed equipped with an adsorbent A continuously, collecting an effluent that passes through the adsorbent A to form a decolored solution; (3) passing the decolored solution of step (2) through a microporous membrane of a drainage to obtain a pretreatment solution, then desalinating the pretreatment solution by electrodialysis to obtain a desalination solution; (4) passing the desalination solution of step (3) through a fixed bed equipped with an adsorbent B continuously under room temperature, collecting an effluent that passes through the adsorbent B, obtaining a supersaturated syrup by concentrating the effluent that passes through the adsorbent B under reduced pressure at 45˜60° C.; and (5) crystallizing the supersaturated syrup and obtaining white powder of L-arabinose after drying; wherein the adsorbent A is one of granular activated carbon, non-polar macroporous polystyrene adsorption resin, weak polar macroporous polystyrene adsorption resin, non-polar macroporous acrylic adsorption resin, weak polar macroporous acrylic adsorption resin, non-polar gel-type polystyrene adsorption resin, weak polar gel-type polystyrene adsorption resin, weak polar gel-type polystyrene acid adsorption resin, non-polar gel-type acrylic adsorption resin and weak polar gel-type acrylic adsorption resin; wherein the process of the electrodialysis consists of the steps of: circulating the pretreatment solution in concentrated solution chamber and pure water in diluted solution chamber of an electrodialysis instrument respectively through electrode chamber that contains Na2SO4 as polar water and desalinating for 2˜5 hours under constant voltage and velocity; wherein the adsorbent B is one of non-polar macroporous polystyrene adsorption resin, non-polar macroporous acrylic adsorption resin, non-polar gel-type polystyrene acid adsorption resin, non-polar gel-type acrylic adsorption resin, granular activated carbon, and silica gel bonded with C18 or C30; wherein the process of the crystallization comprises the steps of: dissolving the supersaturated syrup of step (4) in alcohol, cooling the temperature to ambient temperature, inducing crystallization by adding some L-arabinose, filtering after crystallizing for 24˜72 hours, and obtaining pure L-arabinose with purity of 98% or higher after drying in a vacuum oven at 50˜60° C.; the alcohol is methanol or ethanol, the ratio of alcohol volume to the supersaturated syrup by weight is (6˜10) L: 1 kg, the cooling rate is 0.2˜3° C./min and crystallization temperature range is -5˜10° C.; wherein the inorganic acid is sulfuric acid, hydrochloric acid, phosphoric acid or mixture of two thereof and molar concentration of H+is 1˜6 mol/L; wherein the hydrolysis time is 1˜5 hours; wherein decolorization temperature of step (2) is 20˜55° C. and flow rate is 0.5˜3 bed volume/hour; wherein the mass concentration of Na2SO4 is 3% -˜8% and the volume ratio of the pretreatment solution and pure water is 1: 1˜3; and wherein the desalination conditions are as follows: operating voltage is 20˜30 V and the solutions flow rate is 10˜30 L/hours.