Heterogeneous Precious Metal Catalysts for Highly Efficient Hydrogenation Reaction

Heterogeneous catalysts are highly sustainable because they are easy to recover and reuse, which is also important from the perspective of the SDGs. Therefore, hydrogenation reactions using heterogeneous catalysts can be designed as economical and environmentally friendly processes. Hydrogenation is a type of reduction reaction, in which hydrogen adds to multiple bonds, nitro groups, benzyl groups, carbonyl groups, and even aromatic rings. These transformations are useful in organic synthesis chemistry and are widely used from laboratory scale to process chemistry. Hydrogenation reactions generally use hydrogen gas as the hydrogen source and proceed in the presence of a catalyst. The catalysts used are classified into homogeneous catalysts, mainly metal complexes, and heterogeneous catalysts, in which a metal is supported on a carrier. Heterogeneous catalysts in particular are solid catalysts that do not dissolve in the reaction system, making post-reaction treatment easy, and in many cases the catalyst can be separated by filtration alone and highly pure products can be obtained.

Hydrogenation reactions using heterogeneous catalysts are widely used as a useful method due to their high practicality and reusability, but there are some challenges. For example, when multiple reducible functional groups coexist, selective hydrogenation of the target functional group can be difficult. In addition, many heterogeneous catalysts often require harsh reaction conditions such as high temperature and pressure to fully exert their reaction activity. In addition, the catalyst may cause clogging during filtration after the reaction, and it may not be sufficiently dispersible in the reaction system. These issues are important from the perspective of reaction scalability and operability, and they need to be resolved in future catalyst design and process development.

We have added 14 products to our lineup of activated carbon supported precious metal catalysts. In addition to general-purpose catalysts, we have begun selling product groups for various applications, including egg-shell catalysts with improved precious metal support methods, catalysts with improved filterability and filtration speed, catalysts that suppress side reactions such as dehalogenation due to sulfur poisoning, and catalysts that are useful for adjusting the liquid pH of the reaction solution. These catalysts are useful for screening tests aimed at optimizing reaction conditions and improving selectivity in hydrogenation reactions, as well as process development toward scale-up manufacturing.

1. Heterogeneous Precious Metal Catalysts for Highly Efficient Hydrogenation Reaction

2. Introduction Heterogeneous catalysts are highly sustainable because they are easy to recover and reuse, which is also important from the perspective of the SDGs. Therefore, hydrogenation reactions using heterogeneous catalysts can be designed as economical and environmentally friendly processes. Hydrogenation is a type of reduction reaction, in which hydrogen adds to multiple bonds, nitro groups, benzyl groups, carbonyl groups, and even aromatic rings. These transformations are useful in organic synthesis chemistry and are widely used from laboratory scale to process chemistry.  Hydrogenation reactions generally use hydrogen gas as the hydrogen source and proceed in the presence of a catalyst. The catalysts used are classified into homogeneous catalysts, mainly metal complexes, and heterogeneous catalysts, in which a metal is supported on a carrier.

3. Heterogeneous catalysts in particular are solid catalysts that do not dissolve in the reaction system, making post-reaction treatment easy, and in many cases the catalyst can be separated by filtration alone and highly pure products can be obtained. Hydrogenation reactions using heterogeneous catalysts are widely used as a useful method due to their high practicality and reusability, but there are some challenges. For example, when multiple reducible functional groups coexist, selective hydrogenation of the target functional group can be difficult. In addition, many heterogeneous catalysts often require harsh reaction conditions such as high temperature and pressure to fully exert their reaction activity. In addition, the catalyst may cause clogging during filtration after the reaction, and it may not be sufficiently dispersible in the reaction system. These issues are important from the perspective of reaction scalability and operability, and they need to be resolved in future catalyst design and process development.

4. We have added 14 products to our lineup of activated carbon supported precious metal catalysts. In addition to general-purpose catalysts, we have begun selling product groups for various applications, including egg-shell catalysts with improved precious metal support methods, catalysts with improved filterability and filtration speed, catalysts that suppress side reactions such as dehalogenation due to sulfur poisoning, and catalysts that are useful for adjusting the liquid pH of the reaction solution. These catalysts are useful for screening tests aimed at optimizing reaction conditions and improving selectivity in hydrogenation reactions, as well as process development toward scale-up manufacturing.

5. Products Product Number Product Name P3300 Palladium 5% on Carbon, M type (wetted with ca. 55% Water) P3299 Palladium 10% on Carbon, M type (wetted with ca. 55% Water) P3302 Palladium 5% on Carbon, PH type (wetted with ca. 55% Water) P3303 Palladium 7.5% on Carbon, PH type (wetted with ca. 53% Water) P3301 Palladium 10% on Carbon, MA type (wetted with ca. 53% Water) P3294 Palladium 5% on Carbon, EA type (wetted with ca. 55% Water) P3295 Palladium 5% on Carbon, EB type (wetted with ca. 55% Water) P3297 Palladium 5% on Carbon, LA type (wetted with ca. 55% Water) P3298 Palladium 5% on Carbon, LB type (wetted with ca. 55% Water) P3304 Platinum 2% on Carbon (wetted with ca. 55% Water) P3306 Platinum 5% on Carbon (wetted with ca. 55% Water) P3305 Platinum 3% on Carbon (wetted with ca. 55% Water) (Modified by Sulfur) R0322 Ruthenium 5% on Carbon, SD type (wetted with ca. 55% Water) These products are sold as wetted form containing  ca.  50% water because it can be flammable when dried. These products have been merchandized under the technical partnership with Kawaken Fine Chemicals Co., Ltd. Information of the features and recommended reactions for each products is available in our product brochure. If you would like to purchase in bulk, please contact us on [email protected]

6. Advantages 14 product lineup containing palladium, platinum, or ruthenium supported on carbon Includes catalysts for specialized use as well as catalysts for general use Suppresses dehalogenation and allows chemoselective hydrogenation

7. Features and Reactivities of Products  (*) reaction examples are described in this page.

8.  (*) reaction examples are described in this page.

9. Chemoselectivity of Palladium Catalysts ‡ This table is reference data. Actual reactivities can defer depending on conditions and substrates.

10. Applications Selective Hydrogenation with Non-Dehalogenation Sulfur modified Pt/C (Product No.  P3305 ) is poisoned and its ability of hydrogenation is controlled, so that almost no dehalogenations occur even if nitro groups and multiple bonds co-exist.

11. Hydrogenation under Low Pressure and at Low Temperature Hydrogenations generally require high pressure conditions in order to promote reactions. LA type and LB type Pd /C are highly activated, which enables hydrogenation under low pressure and at low temperature. As a result, side reactions are suppressed even though competitive functional groups exist. In the presented reactions, pyridine and indole moieties do not affect the reaction and carboxy groups are tolerable.

12. Hydrogenation of Aromatic Nucleus In this reaction, target monomers are efficiently obtained because almost no C-O hydrogenolysis occur. Alicyclic diol monomers are applicable to the synthesis of polyester resins and polycarbonate resins with high heat resistance and transparency.

13. Synthesis of sp 3  Carbon-enriched and Three-dimensional Building Blocks sp 3  carbon-enriched scaffolds are preferred to flat aromatic rings in the field of drug discovery research. sp 3  carbons are reported to enhance hydrophilicity and to improve stability to metabolism. Hydrogenation of aromatic nucleus are used.

14. Pd /C Catalyst Balancing Ease Filtration Property and High Dispersibility Heterogeneous catalysts can be removed by filtration. The filtration speed will influence work efficiency. Filtration properties and dispersity have a trade-off relationship, so catalysts with small diameters have high reactivity because of their high dispersity , but catalysts tend to become clogged, which reduces the filtration speed. AD type Pd /C has controlled size, so it has both good filtration property and dispersity .

15. PLEASE CONTACT TCI FOR MORE INFORMATION www.TCIchemicals.com/IN/en | [email protected]