# US 6,296,829 B1 · Process for the aqueous purification of hydrogen peroxide containing impurities > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,296,829 B1 - Document ID: US6296829B1 - Status: Granted - Kind: B1 - Application number: 09/419,878 - Filed: 1999-10-15 - Granted: 2001-10-02 - Earliest claimed: 1998-10-16 - Assignees: L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude - Inventors: Christine Devos; Didier Demay - Web page: https://patentgrep.com/patent/US6296829B1 ## CPC - C01B 15/0135: {Purification by solid ion-exchangers or solid chelating agents} - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} ## Abstract Process for purifying an aqueous hydrogen peroxide solution containing impurities, some of which are in ionic form, in which the said aqueous solution is purified by passing it through at least one first resin of anionic type in order to remove at least some anionic impurities, and then through a second resin of cationic type in order to remove at least some of the cationic impurities, or vice versa, characterized in that at least a first and a second bed of a first resin of anionic type are arranged in parallel, in that the aqueous solution is directed alternately onto the said first or the said second bed, and in that changeover from the first bed to the second bed (or vice versa) is carried out when the said first [lacuna] is at least partially saturated with at least one of the anions constituting the anionic impurities. ## Claims ### Claim 1 Process for purifying an aqueous hydrogen peroxide solution containing impurities, some of which are in ionic form, comprising: passing said solution (i) through at least one first, anionic resin to remove at least some anionic impurities, and then through a second, cationic resin in order to remove at least some cationic impurities, or (ii) through at least one first, cationic resin to remove at least some cationic impurities, and then through a second, anionic resin to remove at least some cationic impurities, wherein at least a first and a second bed of the anionic resin are arranged in parallel, wherein the aqueous solution is directed alternately to said first or said second bed, and changeover from the first bed to the second bed or from the second bed to the first bed is carried out when the resin contained in the first bed or the second bed, respectively, is at least partially exchanged with at least one of the anions constituting the anionic impurities, and wherein at least one of the beds of at least one of the resins is provided with safety means capable of triggering a rinsing of at least one of the beds when an anomaly is detected in the progress of at least one process step, wherein the anomaly is based on one or more of hydrogen peroxide solution flow rate, hydrogen peroxide solution temperature, abnormal functioning of a utility service, and actuation of an emergency switch. ### Claim 2 (depends on 1) Process according to claim 1, wherein each of the beds of anionic resin arranged in parallel is used successively until at least partially exchanged with at least one of the anions constituting the anionic impurities. ### Claim 3 (depends on 1) Process according to claim 1, wherein at least one of the beds comprises a plurality of resins, stacked in successive beds or mixed together, which are capable of exchanging the anionic impurities with a different selectivity. ### Claim 4 (depends on 1) Process according to claim 1, wherein the concentration of organic anionic impurities in the aqueous solution is larger than the concentration of inorganic anionic impurities in the aqueous solution. ### Claim 5 (depends on 1) Process according to claim 1, wherein essentially all of the organic anionic impurities in the aqueous solution are in the form of acetates and formates. ### Claim 6 (depends on 1) Process according to claim 1, wherein essentially all of the inorganic anionic impurities in the aqueous solution are in the form of nitrates. ### Claim 7 (depends on 1) Process according to claim 1, wherein the aqueous hydrogen peroxide solution to be purified has a concentration of 30% by volume, and wherein the concentration of acetate ions in the aqueous solution to be purified is at least about 300×10−3 millieq/l. ### Claim 8 (depends on 1) Process according to claim 1, wherein the aqueous hydrogen peroxide solution to be purified has a concentration of 30% by volume, and wherein the concentration of acetate ions in the aqueous solution to be purified is not more than about 2000×10−3 millieq/l. ### Claim 9 (depends on 1) Process according to claim 1, wherein the aqueous hydrogen peroxide solution to be purified has a concentration of 30% by volume, and wherein the concentration of nitrate ions in the aqueous solution to be purified is at least about 30×10−3 millieq/l. ### Claim 10 (depends on 1) Process according to claim 1, wherein the aqueous hydrogen peroxide solution to be purified has a concentration of 30% by volume, and wherein the concentration of nitrate ions in the aqueous solution to be purified is not more than about 100×10−3 millieq/l. ### Claim 11 (depends on 1) Process according to claim 1, wherein the flow rate of hydrogen peroxide per volume of resin is between 4 and 40 h−1. ### Claim 12 (depends on 11) Process according to claim 11, wherein the flow rate of hydrogen peroxide per volume of resin is between 10 and 30 h−1. ### Claim 13 (depends on 12) Process according to claim 12, wherein the flow rate of hydrogen peroxide per volume of resin is between 15 and 25 h−1. ### Claim 14 (depends on 1) Process according to claim 1, wherein at least one of the anionic resins used is capable of absorbing acetate and/or nitrate ions. ### Claim 15 (depends on 1) Process according to claim 1, wherein at least one of the anionic resins used is a copolymer of styrene and divinylbenzene. ### Claim 16 (depends on 15) Process according to claim 15, wherein at least one of the resins used comprises a functional group which is a quaternary ammonium group, obtained by amination of a chloromethylated copolymer of styrene and divinylbenzene. ### Claim 17 (depends on 16) Process according to claim 16, wherein the ionic form of at least one of the resins used is HCO3−. ### Claim 18 (depends on 1) Process according to claim 1, wherein the cationic resin is arranged in the form of one or more beds, each bed comprising at least one cationic resin. ### Claim 19 (depends on 18) Process according to claim 18, wherein at least one of the cationic resins is a copolymer of styrene and divinylbenzene. ### Claim 20 (depends on 19) Process according to claim 19, wherein the copolymer is strongly acidic. ### Claim 21 (depends on 20) Process according to claim 20, wherein the ionic form of at least one of the cationic resins used is H+. ### Claim 22 (depends on 1) Process according to claim 1, wherein the cationic resin is dispersed in the form of a plurality of beds arranged in series and/or in parallel. ### Claim 23 (depends on 18) Process according to claim 18, wherein at least one of the cationic resins is capable of adsorbing at least one of the ions Na+, Al3+ and Fe3+. ### Claim 24 (depends on 1) Process according to claim 1, wherein the aqueous hydrogen peroxide solution to be purified comprises between 0.5×10−3 millieq/l and 20×10−3 millieq/l of sodium. ### Claim 25 (depends on 1) Process according to claim 1, wherein the aqueous hydrogen peroxide solution to be purified comprises between 2×10−3 and 20×10−3 millieq/l of aluminum. ### Claim 26 (depends on 1) Process according to claim 1, wherein the aqueous hydrogen peroxide solution to be purified comprises between 0.05×10−3 and 0.5×10−3 millieq/l of iron. ### Claim 27 (depends on 1) Process according to claim 1, wherein the aqueous hydrogen peroxide solution to be purified is of industrial pure grade quality. ### Claim 28 (depends on 1) Process according to claim 1, wherein the aqueous hydrogen peroxide solution to be purified is placed in contact with an adsorbent of neutral organic matter before being placed in contact with the first of the at least one anionic and cationic resin. ### Claim 29 (depends on 1) Process according to claim 1, wherein the rinsing is carried out with water. ### Claim 30 (depends on 29) Process according to claim 29, wherein the resistivity of the water is greater than or equal to 18 MΩ·cm at 25° C. ### Claim 31 (depends on 30) Process according to claim 30, wherein the safety means comprise means for measuring the flow rate of hydrogen peroxide solution through the at least one bed of resin, so as to trigger the rinsing of said at least one resin bed when the flow rate value measured is less than a predetermined value of four times the volume of resin in the bed per hour. ### Claim 32 (depends on 1) Process according to claim 1, wherein the safety means comprise at least one probe for detecting the temperature of the hydrogen peroxide solution which is in contact with the at least one bed of resin. ### Claim 33 (depends on 1) Process according to claim 1, wherein the safety means are also sensitive to abnormal functioning of a utility service used during the process and/or to actuation of an emergency switch. ### Claim 34 (depends on 33) Process according to claim 33, wherein the utility service is electricity, water, or compressed-air supply.