Catalytic Transfer Hydrogenation.docx

Fajar Firstya Adam 02211850010006 Teknik Reaksi Kimia Lanjutan (Program Pascasarjana)

REVIEW Catalytic Transfer Hydrogenation Transformation of organic synthesis compounds or biomass derived compounds often deal with complicated structure of polyfunctional groups of its molecules. One of significant method and interesting in practical research is examining Catalytic Transfer Hydrogenation reaction which promising a new pathway of chemical conversion in especially reductive reaction techniques eventhough this idea have been proposed and recently this issue, somehow revived. This techniques provide of utilization of H atom bond scission from other hydrogen source rather than using molecular hydrogen gaseous phase. Some disadvantages of using pressurized hydrogen is easily ignited moreover in industrial large scale which may be took a huge risks. Along with Green Chemistry terminology, a philosophy of chemical research engineering which lately discussed in much publication then promotes the optimization of designing process with reducing of harmful hazardous substance. Then, with those drawback mentioned earlier, the catalytic transfer hydrogenation techniques should be considered. This technique used for reduction of unsaturated organic compound with the aid of hydrogen source in a present of catalyst. Catalyst could be homogenous or heterogenous. The mechanism of catalytic transfer hydrogenation can occur according to two mechanism, hydricidic route which assisted by transition-metals or direct hydrogen transfer by non-transition metals. Hydrogen source often utilize a solvent which can release hydrogen or donoring its hydrogen most of solvent which can produce is organic solvent, but anorganic compound, hydrazine should be an alternative. Essentially, the kinetics and rate of catalytic transfer hydrogenation reaction affected by mostly, the nature of donor and solvent, which the origin of hydrogen molecule, whereas in reductive reaction with pressurized hydrogen, the pressure of hydrogen gases play the key role. Organic compound which suitable for hydrogen donor, should have a very low oxidating potential, high reactivity, its interaction with catalyst and sufficient of solubility with reactant. Mostly, unstaturated alcohol or short-chain alcohol often used as hydrogen source because, not only as solvent but also as hydrogen donor another solvent could inhibit transfer reaction, with aldehid group such as nitrobenzaldehid. Another variable which very critical for reaction is temperature. Hydrogen transfer from donor to acceptor occurs in a high temperature, but it can be lowered about 50% thanks to the present of metal catalyst which provide this reaction at mild condition. And the last variables which truly determine the reaction is catalyst, because, in the catalyst, providing a space where hydrogen transfer reaction took place. Not only hydrogen transfer but also intermediate product such as formation of metal-hydride, rearrangement of dehydrogenation of donor molecules on metal catalyst site, its stereochemical, how transfer would be affected to the acceptor, including several scission of functional groups from donor and acceptor, can be determine how mechanism should be occurred, and all of these phenomenon should be specifically revealed to give a better selectivity from catalytic transfer hydrogenation reaction on several organic substances. Application of these technique path in kinetic engineering have been used for transformation several substances, depends on its target compound, for example, reduction of double bond such as olefin, acetylene, and carbonyl compound, hydrogenolysys reaction for nitil, halide and amine compound. Recently this technique applied in degradation or transformation of complex substance such as lignin, glycerol or starch. By the end of this review and information, hopefully this technique can be explored for further development, research and study based this idea shoud be conducted and revisited. Keyword : Hydrogen donor, Catalytic Transfer Hydrogenation, Organic Transformation, Catalyst

Fajar Firstya Adam 02211850010006 Teknik Reaksi Kimia Lanjutan (Program Pascasarjana)

Further Information and Cited publication, Musolino, M.G., Scarpino, L.A., Maurellio, F., Pietropaolo, R (2009). "Selective Transfer Hydrogenolysis promoted by supported Palladium Catalys in the absence of Hydrogen" Green Chem 2009 11, (153-158) Gilkey, M.J., B. Xu (2016) " Heterogeneous catalytic transfer hydrogenation as an effective pathway in biomass upgrading". ACS Catalysis. 2016, 6, 1420−1436 Wang, D., Didier A (2015) " The Golden age of Transfer Hydrogenation". Chem. Review 2015, 115: (6621−6686) Wang, J ., R Nie, L Xu, X Lyu, X Lu (2019) " Catalytic transfer hydrogenation of oleic acid to octadecanol over magnetic recoverable cobalt catalysts". Green Chem 2019 2: (6621−6686) Wolfson, A., I Grinberg, D Tavor (2019) " Solvent Selection in Transfer Hydrogenation and Suzuki Cross-coupling ". Energy and Environmental Engineering 2013 1: (17-23) Zhang, J (2018) " Catalytic transfer hydrogenolysis as an efficient route in cleavage of lignin and model compounds". Green Energy & Environment 2018 3: (328-334) Johnstone, R. A. W., Wilby, A. H., (1985) " Heterogeneous Catalytic Transfer Hydrogenation and Its Relation to Other Methods for Reduction of Organic Compounds". Chem. Rev. 1985, 85, (129-170) Johnstone, R. A. W., Wilby, A. H., (1981) “Metal-assisted reactions part 10”. Tetrahedron 1981, 37,3667–3670. Gandarias, I., P.L.Arias J. Requies M. El Doukkali M.B.Güemez (2011). "Liquid Phase Glycerol Hydrogenolysis, to 1,2-Propanediol under nitrogen pressure using 2-propanol as Hydrogen Source". Journal of Catalyst 282 (2011) 237-247