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WO-2026093194-A1 - CATALYTIC HYDRODECHLORINATION OF TRICHLOROMETHANE

WO2026093194A1WO 2026093194 A1WO2026093194 A1WO 2026093194A1WO-2026093194-A1

Abstract

Use of a catalyst comprising a carrier, an active metal supported on the carrier, and an optional second metal supported on or added to the carrier, for the hydrodechlorination of trichloromethane, the catalyst being selected from: (i) a Pt-Mo/Al 2 O 3 catalyst, where the carrier is alumina (Al 2 O 3 ), the active metal is platinum (Pt), and the second metal is molybdenum (Mo); (ii) a Pt-Ag/Al 2 O 3 catalyst, where the carrier is alumina (Al 2 O 3 ), the active metal is platinum (Pt), and the second metal is silver (Ag); (iii) a Pt-Co/Al 2 O 3 catalyst, where the carrier is alumina (Al 2 O 3 ), the active metal is platinum (Pt), and the second metal is cobalt (Co); or (iv) an Ir/SiO 2 catalyst, wherein the carrier is silica (SiO 2 ), and the active metal is iridium (Ir).

Inventors

  • SUN, Chunning
  • VAN LARE, CORNELIS ELIZABETH JOHANNUS
  • ZWIJNENBURG, AALBERT
  • WECKHUYSEN, BERT MARC

Assignees

  • NOBIAN INDUSTRIAL CHEMICALS B.V.

Dates

Publication Date
20260507
Application Date
20251027
Priority Date
20241101

Claims (15)

  1. 378.0861 PC CLAIMS: 1 . Use of a catalyst comprising a carrier, an active metal supported on the carrier, and an optional second metal supported on or added to the carrier, for the hydrodechlorination of trichloromethane, the catalyst being selected from: (i) a Pt-Mo/AI 2 O 3 catalyst, where the carrier is alumina (AI 2 O 3 ), the active metal is platinum (Pt), and the second metal is molybdenum (Mo); (ii) a Pt-Ag/AI 2 O 3 catalyst, where the carrier is alumina (AI 2 O 3 ), the active metal is platinum (Pt), and the second metal is silver (Ag); (iii) a Pt-Co/AI 2 O 3 catalyst, where the carrier is alumina (AI 2 O 3 ), the active metal is platinum (Pt), and the second metal is cobalt (Co); or (iv) an I r/SiO 2 catalyst, wherein the carrier is silica (SiO 2 ), and the active metal is iridium (Ir).
  2. 2. A use as claimed in claim 1 , wherein the catalyst has a total metal loading of from 0.5 to 3.0 wt.%, preferably of from 0.7 to 2.5 wt.%, and more preferably of from 0.8 to 2.1 wt.%, based on the total weight of the catalyst.
  3. 3. A use as claimed in claim 1 or claim 2, wherein the Pt-Mo/AI 2 O 3 catalyst contains from 0.7 to 1 .3 wt.% Pt and from 0.1 to 1 .0 wt.% Mo, preferably from 0.8 to 1 .2 wt.% Pt and from 0.2 to 0.7 wt.% Mo, and more preferably from 0.9 to 1 .1 wt.% Pt and from 0.3 to 0.6 wt.% Mo, based on the total weight of the catalyst.
  4. 4. A use as claimed in claim 1 or claim 2, wherein the Pt-Ag/AI 2 O 3 catalyst contains Pt and Ag in a molar ratio of from 5:1 to 1 :5, preferably of from 3:1 to 1 :3, more preferably of from 2.5:1 to 1 :1 , and most preferably of from 2:1 to 1 .5:1 .
  5. 5. A use as claimed in claim 1 or claim 2, wherein the Pt-Co/AI 2 O 3 catalyst contains from 0.7 to 1 .3 wt.% Pt and from 0.1 to 2.0 wt.% Co, preferably from 0.8 to 1 .2 wt.% Pt and from 0.2 to 0.7 wt.% Co, and more preferably from 0.9 to 1 .1 wt.% Pt and from 0.3 to 0.6 wt.% Co, based on the total weight of the catalyst.
  6. 6. A use as claimed in any preceding claim, wherein the Pt has an average particle size of less than 10 nm, preferably less than 5 nm, and more preferably less than 2 nm, as determined by electron microscopy. 378.0861 PC
  7. 7. A use as claimed in any preceding claim, wherein Mo, Co or Ag has an average particle size of less than 2 nm, preferably less than 1 nm, and more preferably less than 0.5 nm, as determined by electron microscopy.
  8. 8. A use as claimed in any preceding claim, wherein the alumina carrier is gamma phase alumina.
  9. 9. A use as claimed in any preceding claim, wherein the alumina carrier has a Brunauer- Emmett-Teller (BET) surface area greater than 150 m 2 /g, preferably greater than 160 m 2 /g.
  10. 10. A use as claimed in any preceding claim, wherein the silica and/or alumina carrier has a primary particle less than 100 nm as determined by electron microscopy.
  11. 11 . A process for producing dichloromethane, chloromethane and/or methane from trichloromethane, the process comprising, under an oxygen-free atmosphere: in a reducing stage, contacting a catalyst with a hydrogen-containing gas stream at a temperature of from 250 to 400 °C, preferably 300 to 350 °C, thereby forming a reduced catalyst; and in a reaction stage, contacting the reduced catalyst with a trichloromethane- containing gas stream at a temperature of from 100 to 350 °C, wherein the catalyst comprises a carrier, an active metal supported on the carrier, and an optional second metal supported on or added to the carrier, and is selected from: (i) a Pt-Mo/AI 2 O 3 catalyst, where the carrier is alumina (AI2O3), the active metal is platinum (Pt), and the second metal is molybdenum (Mo); (ii) a Pt-Ag/AI 2 O 3 catalyst, where the carrier is alumina (AI 2 O 3 ), the active metal is platinum (Pt), and the second metal is silver (Ag); (iii) a Pt-Co/AI 2 O 3 catalyst, where the carrier is alumina (AI 2 O 3 ), the active metal is platinum (Pt), and the second metal is cobalt (Co); or (iv) an lr/SiO 2 catalyst, wherein the carrier is silica (SiO 2 ), and the active metal is iridium (Ir).
  12. 12. A process as claimed in claim 1 1 , wherein the trichloromethane-containing gas stream comprises hydrogen and trichloromethane in a molar ratio of at least 10:1 , preferably at least 15:1 , more preferably at least 20:1 , and most preferably at least 40:1 .
  13. 13. A process as claimed in claim 1 1 or 12, wherein the reaction stage is carried out at a temperature of from 120 to 220 °C, preferably of from 150 to 200 °C. 378.0861 PC
  14. 14. A process as claimed in any of claims 11 to 13, further comprising: in a separating stage, separating the dichloromethane from the chloromethane and/or methane, preferably by distillation.
  15. 15. A process as claimed in any of claims 1 1 to 14, having a dichloromethane productivity above 500 mmol • g C at -1 • h -1 , preferably above 600 mmol • g C at -1 • h -1 , more preferably above 700 mmol • g C at -1 • h’ 1 , and most preferably above 800 mmol • g C at -1 • h’ 1 .

Description

378.0861 PC HYDRODECHLORINATION CATALYST Technical field The present invention is directed to new hydrodechlorination catalysts, and in particular, to new hydrodechlorination catalysts that enable the selective hydrodechlorination of trichloromethane (CHCI3) into dichloromethane (CH2CI2). Background Industrially, chloromethanes (i.e., carbon tetrachloride (CCI4), trichloromethane (CHCI3), dichloromethane (CH2CI2), and chloromethane (CH3CI)) are typically produced by reacting methane (CH4) with chlorine (Cl2). The chlorination reaction proceeds via a low-selectivity radical mechanism, meaning that the products stream includes a mixture of the four possible chloromethanes. As market conditions can vary, there is a need for production processes that exhibit a high degree of flexibility, such that the composition of the chloromethane products stream can be optimized. Currently, the higher chloromethanes (i.e., CCI4 and CHCI3) are the least desired in the market. Because of this, their economic value is lower, and in some cases these compounds are seen as undesired and incinerated. In response, the catalyzed reaction of CCI4 with H2 to CHCI3 and HCI (also called hydrodechlorination) has been studied and some suitable catalysts have been developed. These are commonly based on noble metals platinum (Pt) and palladium (Pd), with activated carbon, alumina (AI2Os), or silica (SiO2) as carriers. The analogous hydrodechlorination reaction of CHCI3 into CH2CI2 is more challenging and has been less investigated. However, CH2CI2 is a useful solvent for many chemical processes. It is also used in the food industry to decaffeinate coffee and tea, and as a blowing agent for polyurethane foams. Accordingly, there is a need for a reaction that can convert CHC into CH2CI2 (and CH3CI and/or CH4). 378.0861 PC Summary of the Disclosure In a first aspect, the present invention is directed to the use of a catalyst comprising a carrier, an active metal supported on the carrier, and an optional second metal supported on or added to the carrier, for the hydrodechlorination of trichloromethane, the catalyst being selected from: (i) a Pt-Mo/AI2O3 catalyst, where the carrier is alumina (AI2O3), the active metal is platinum (Pt), and the second metal is molybdenum (Mo); (ii) a Pt-Ag/AI2O3 catalyst, where the carrier is alumina (AI2O3), the active metal is platinum (Pt), and the second metal is silver (Ag); (iii) a Pt-Co/AI2O3 catalyst, where the carrier is alumina (AI2O3), the active metal is platinum (Pt), and the second metal is cobalt (Co); or (iv) an I r/SiO2 catalyst, wherein the carrier is silica (SiO2), and the active metal is iridium (Ir). Advantageously, the use of a Pt-Mo/AI2O3 catalyst, a Pt-Ag/AI2O3 catalyst, a Pt-Co/AI2O3 catalyst, or an lr/SiO2 catalyst, in accordance with the first aspect of the invention, has been found to enable surprisingly selective hydrodechlorination of trichloromethane with hydrogen into dichloromethane. Furthermore, these catalysts can be easily produced using wetness impregnation methods and have been found to exhibit excellent stability during the hydrodechlorination reaction. The use of these catalysts in accordance with the first aspect of the invention therefore provides a flexible, economic, and long-term route to the lower chloromethanes in response to external market dynamics. In a second aspect, the invention provides a process for producing dichloromethane, chloromethane and/or methane from trichloromethane, the process comprising, under an oxygen- free atmosphere: in a reducing stage, contacting a catalyst with a hydrogen-containing gas stream at a temperature of from 250 to 400 °C, preferably 300 to 350 °C, thereby forming a reduced catalyst; and in a reaction stage, contacting the reduced catalyst with a trichloromethane-containing gas stream at a temperature of from 100 to 350 °C, wherein the catalyst comprises a carrier, an active metal supported on the carrier, and an optional second metal supported on or added to the carrier, and is selected from: (i) a Pt-Mo/AI2O3 catalyst, where the carrier is alumina (AI2O3), the active metal is platinum (Pt), and the second metal is molybdenum (Mo); (ii) a Pt-Ag/AI2O3 catalyst, where the carrier is alumina (AI2O3), the active metal is platinum (Pt), and the second metal is silver (Ag); 378.0861 PC (iii) a Pt-Co/AI2O3 catalyst, where the carrier is alumina (AI2O3), the active metal is platinum (Pt), and the second metal is cobalt (Co); or (iv) an I r/SiO2 catalyst, wherein the carrier is silica (SiO2), and the active metal is iridium (Ir). As shown in the Examples below, this Pt-Mo/AI2O3, Pt-Ag/AI2O3, Pt-Co/AI2O3, or lr/SiO2 catalysed hydrodechlorination reaction provides a highly selectivity and highly productive route to dichloromethane. The process therefore offers a less costly and more environmentally friendly outlet for trichloromethane. Figures Figure 1 is a schematic diagram of the catalytic performance testing used in the Examples.