# US 11,027,245 B1 · Process for continuous dissolution of a solid in a reaction medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,027,245 B1 - Document ID: US11027245B1 - Status: Granted - Kind: B1 - Application number: 16/628,092 - Filed: 2018-06-28 - Published: 2021-05-20 - Granted: 2021-06-08 - Earliest claimed: 2017-07-05 - Assignees: Evonik Operations GmbH - Applicants: Evonik Operations GmbH - Inventors: Dirk Bröll; Thorsten Noll - Web page: https://patentgrep.com/patent/US11027245B1 ## CPC - B01F 21/30: {Workflow diagrams or layout of plants, e.g. flow charts; Details of workflow diagrams or layout of plants, e.g. controlling means} - B01D 3/143: {by two or more of a fractionation, separation or rectification step} - B01F 21/02: {Methods} - B01J 8/0242: {the fluid flow within the bed being predominantly vertical} - B01J 8/0278: {Feeding reactive fluids (for solid material B01J8/0015)} - C07C 51/573: Separation; Purification; Stabilisation; Use of additives - B01J 2208/00787: Bringing the solid in the form of a slurry before feeding it to the reactor - B01J 2219/00038: Processes in parallel - C07C 57/04: Acrylic acid; Methacrylic acid - C07D 279/20: with hydrogen atoms directly attached to the ring nitrogen atom - B01F: MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING (mixing paints B44D3/06) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS - C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08) ## Abstract A process for continuous dissolution of a solid in a reaction medium includes: (a) providing a liquid by withdrawal of a portion of the reaction medium from a first reaction vessel; (b) contacting the liquid provided in (a) with the solid in a second reaction vessel to form a solution of the solid; and (c) recycling the solution formed in step b) into the first reaction vessel. The solid in the second reaction vessel is present in the form of a fixed bed which is traversed by the liquid. ## Claims ### Claim 1 A process for continuous dissolution of a solid in a reaction medium, comprising: a) withdrawing a liquid, which is a portion of the reaction medium, from a first reaction vessel; b) contacting the liquid withdrawn from the first reaction vessel in a) with a solid in a second reaction vessel to form a solution of the solid, wherein the solid in the second reaction vessel is present in a form of a fixed bed which is traversed by the liquid; and c) recycling the solution formed in b) into the first reaction vessel. ### Claim 2 (depends on 1) The process according to claim 1, wherein the reaction medium comprises a liquid phase or a mixture of gaseous and liquid phases, and gaseous constituents are liquefied during the withdrawal in a). ### Claim 3 (depends on 1) The process according to claim 1, wherein the reaction medium comprises at least two chemical components, and before or during the withdrawal in a), the reaction medium is subjected to a separation process so that the portion of the reaction medium withdrawn in a) has a different composition to the reaction medium. ### Claim 4 (depends on 1) The process according to claim 1, wherein the first reaction vessel comprises a rectification column from which the withdrawal in a) is effected. ### Claim 5 (depends on 1) The process according to claim 1, wherein the liquid traverses the fixed bed from bottom to top in b). ### Claim 6 (depends on 1) The process according to claim 1, wherein the second reaction vessel comprises two or more fixed beds connected in parallel. ### Claim 7 (depends on 1) The process according to claim 1, wherein the portion of the reaction medium withdrawn in a) is divided into two substreams, of which only a first of the two substreams is passed through the second reaction vessel and a second of the two substreams is passed by the second reaction vessel as a bypass stream and mixed with the solution formed in b). ### Claim 8 (depends on 1) The process according to claim 1, wherein respective pressure measurements are performed before and after the second reaction vessel and a thus determined pressure difference is used to determine a fill level of the fixed bed. ### Claim 9 (depends on 1) The process according to claim 1, wherein the concentration of the solid in the solution obtained in b) is measured continuously by a UV/VIS spectrometer. ### Claim 10 (depends on 1) The process according to claim 1, wherein the reaction medium comprises: at least one unsaturated carboxylic anhydride of general formula R—C(O)—O—C(O)—R, in which R represents an unsaturated organic radical having 2 to 12 carbon atoms, at least one unsaturated carboxylic acid of general formula R—COOH in which R is as defined above, at least one aliphatic carboxylic anhydride, and at least one corresponding aliphatic carboxylic acid, wherein R is optionally substituted with any desired number of halogen atoms or cyano groups. ### Claim 11 (depends on 10) The process according to claim 10, wherein the reaction medium comprises (meth)acrylic acid, (meth)acrylic anhydride, acetic acid, and acetic anhydride. ### Claim 12 (depends on 10) The process according to claim 10, wherein the solid is phenothiazine. ### Claim 13 (depends on 10) The process according to claim 10, wherein the first reaction vessel comprises a rectification column, and the withdrawal in a) is effected in a top of the rectification column. ### Claim 14 (depends on 10) The process according to claim 10, wherein the portion of the reaction medium withdrawn in a) comprises aliphatic carboxylic acids to an extent of at least 90% by weight. ### Claim 15 (depends on 10) The process according to claim 10, wherein a temperature of the fixed bed is set to a range from 10° C. to 80° C. ### Claim 16 A continuous dissolution system, comprising: a first reaction vessel comprising a reaction medium, and a second reaction vessel comprising a solid, wherein a portion of the reaction medium is withdrawn from the first reaction vessel and introduced to the second reaction vessel, thereby contacting the solid to form a solution of the solid, wherein the solution is recycled back to the first reaction vessel, and wherein the solid is present in a form of a fixed bed. ### Claim 17 (depends on 16) The system according to claim 16, wherein the reaction medium comprises (meth)acrylic acid, (meth)acrylic anhydride, acetic acid, and acetic anhydride, and wherein the solid is phenothiazine.