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EP-4493531-B1 - PROCESS FOR THE PRODUCTION OF ETHYLENE GLYCOL

EP4493531B1EP 4493531 B1EP4493531 B1EP 4493531B1EP-4493531-B1

Inventors

  • GRUTER, GERARDUS JOHANNES MARIA
  • SCHULER, Eric
  • RAVEENDRAN, Shiju Nirappurackal

Dates

Publication Date
20260506
Application Date
20230314

Claims (10)

  1. A process for the production of mono ethylene glycol comprising subjecting an aqueous oxalic acid solution to a hydrogenation reaction in the presence of hydrogen and a metal containing hydrogenation catalyst, wherein the process is a continuous flow process in a fixed bed reactor; wherein the aqueous oxalic acid solution and a hydrogen gas stream are fed to the fixed bed reactor; wherein the reactor comprises a hydrogenation catalyst bed, the catalyst being a supported metal containing hydrogenation catalyst with a total metal loading of from equal to and higher than 2.0 wt % up to equal to and lower than 20.0 wt %; and wherein the hydrogenation reaction is performed at a temperature selected from the range of from equal to and higher than 95°C up to equal to and lower than 125°C, at a hydrogen pressure selected from the range of from equal to and higher than 10 bar H 2 up to equal to and lower than 150 bar H 2 , at a residence time of equal to or longer than 5 minutes up to equal to or lower than 2 hours; to produce mono ethylene glycol with high selectivity of 80% and higher, at a conversion of oxalic acid of 90% to 100%.
  2. The process of claim 1, wherein the reactor is a trickle bed reactor.
  3. The process of claim 1 or 2, wherein the aqueous oxalic acid solution comprises from equal to or higher than 1.0 weight % to equal to or lower than 40 weight % of oxalic acid.
  4. The process of any one of claims 1 to 3, wherein the hydrogenation catalyst contains one or more metals selected from group A metals: platinum, nickel, copper, ruthenium, rhodium and iridium, and optionally one other metal selected from group B metals: tin, bismuth, palladium, rhenium, gold, and antimony.
  5. The process of any one of claims 1 to 4, wherein the hydrogenation catalyst contains ruthenium as group A metal, and preferably one group B metal.
  6. The process of claim 5, wherein the hydrogenation catalyst contains ruthenium and tin.
  7. The process of claim 6, wherein the molar ratio of ruthenium to tin in the catalyst is from 10:1 to 1:10, preferably 5:1 to 1:5, more preferably 5:2 to 1:4.
  8. The process of any one of claims 1 to 7, wherein the catalyst is a trimetallic catalyst containing ruthenium, tin and platinum.
  9. The process of any one of claims 1 to 8, wherein the hydrogenation catalyst is supported on a carrier selected from carbon, silicon carbide, MAX-Phase (Ti 2 Al 2 C), TiO 2 andZrO 2 , preferably carbon or MAX-Phase.
  10. The process of any one of claims 1 to 9, wherein the hydrogenation reaction is performed in a reactor with non-metallic or inert liners, preferably selected from Teflon, glass, PVC, titanium and Hastelloy.

Description

FIELD OF THE INVENTION The present invention relates to a process for the production of ethylene glycol comprising hydrogenation of oxalic acid. BACKGROUND OF THE INVENTION In view of climate change issues, lots of initiatives are developing to decrease the amount of greenhouse gases in the atmosphere. The focus on capturing CO2 is increasing, wherein CO2 is captured mostly from large point sources, such as chemical or power plants, industries with significant CO2 emissions (such as steelmaking), natural gas processing, the production of hydrogen from fossil fuels, etcetera. After capture, the next steps are CO2 storage (CCS) and/or utilization (CCU). The significant difference between storage and utilization is that CCS technologies store CO2 underground so that it cannot re-enter the atmosphere, whereas CCU technologies use CO2 to convert it to more valuable products, such as plastics or biofuels. Notably, while today the traditional fossil sources of energy production can be replaced by net-zero emission methods (at least in theory), this is not the case for the production of materials, like plastics or concrete. Thus, using CO2 for the production of materials will be vital for ensuring a lower impact on natural resources and is one of the few options for realizing negative emissions (provided that at least non-fossil CO2 and renewable energy is used). For example, CO2 can be used to produce oxalic acid (HOOCCOOH), and in turn oxalic acid can be hydrogenated to produce for example glycolic acid (HOCH2COOH; GA) and mono ethylene glycol (HOCH2CH2OH; MEG), which are valuable chemicals for a number of different applications, such as for the production of plastics, and for GA as a preservative in food processing, as a skin care agent in cosmetics, and more. However, although hydrogenation of carboxylic acids is an important organic reaction for the synthesis of useful and valuable chemicals, it is a chemically difficult reaction due to the low reactivity of the carboxy group and the acidic property. This requires for example rational design of catalysts. See: Tamura, M. et al. Recent Developments of Heterogeneous Catalysts for Hydrogenation of Carboxylic Acids to Their Corresponding Alcohols. Asian J. Org. Chem. 2020, 9 (2), 126-143. Thus, the direct reduction of carboxylic acids requires severe conditions. However, high temperatures cannot be used, as oxalic acid starts to decompose above 130°C, leading to CO2 and formate, and further to methane under hydrogenation conditions. As a result, there are only a few disclosures in the art about this particular reaction. In 1955, Carnahan et al. (J.Am.Chem.Soc., 1955, 77 (14), 3766-3768, DOI:10.1021/ja01619a025) reported that glycolic acid could effectively be reduced to mono ethylene glycol above 145°C while using a ruthenium dioxide or ruthenium-on-carbon catalyst. However, very high pressures (650-710 atm., 700-775 atm.) were needed to reach a yield of 80% or higher. They also reported conversion of oxalic acid dihydrate (no solvent) at temperatures between 94 and 170°C using a ruthenium oxide catalyst, and equally high pressures (630-990 atm.) and long reaction times (10.5 hours), to produce a yield of only 47 % of mono ethylene glycol. The catalytic hydrogenation of an aqueous solution of oxalic acid by a ruthenium-carbon catalyst was reported by Santos et al. (Reaction Kinetics, Mechanism and Catalysis (2020) 131:139-151). They investigated in batch mode the reduction of oxalic acid in the presence of a 5 wt.% Ru/C microporous catalyst in a slurry reactor, at a pressure of 80 bar and a temperature range of 120-150°C, under continuous gas flow, with an operation time of 7 hours. They observed the formation of glycolic acid, acetic acid, ethylene glycol, and volatile compounds. Conversions of oxalic acid of above 90% were reached, however with highest operating selectivity of only 16% (at 130 °C) for ethylene glycol, further a selectivity of 63% (at 120 °C) for glycolic acid and 87% (at 150 °C) for volatile products, respectively. WO2017134139 discloses a method of preparing glycolic acid and/or ethylene glycol, the method at least comprising the steps of: (a) providing an aqueous oxalic acid containing stream having a molar ratio of water/oxalic acid of above 5.0; (b) subjecting the aqueous oxalic acid containing stream provided in step (a) to hydrogenation in the presence of a hydrogenation metal catalyst and hydrogen, thereby obtaining a glycolic acid containing stream; and (c) optionally subjecting the glycolic acid containing stream obtained in step (b) to hydrogenation in the presence of a hydrogenation metal catalyst and hydrogen, thereby obtaining an ethylene glycol (HOCH2CH2OH) containing stream. All the examples of WO2017134139 work in batch mode. The highest selectivity for ethylene glycol reported in the batch process of WO2017134139 is 70% at a conversion of oxalic acid of 99%, produced after a reaction time of in total 18 hours at 90 - 120°C (subs