I am going to analyze the issue of organic chemistry in the news for this purpose I have chosen the article “Asymmetric heterogeneous catalytic hydrogenation; is it a useful tool for the synthetic organic chemist?” from the ARKIVOC journal, written by Antal Tungler. This article gives a description of the value of different methods of asymmetric hydrogenation and summary of results achieved during the experiments and further perspectives in this sphere of study.
In the current essay I am going to analyze the issue of organic chemistry in the news for this purpose I have chosen the article “Asymmetric heterogeneous catalytic hydrogenation; is it a useful tool for the synthetic organic chemist?” from the ARKIVOC journal, written by Antal Tungler. The article concerns the research conducted at the Department of Chemical Technology within the Budapest University of Technology and Economics; it is dedicated to Professor Dr. Sandor Antus on the occasion of his 60th birthday.
This article gives a description of the value of different methods of asymmetric hydrogenation and summary of results achieved during the experiments and further perspectives in this sphere of study. Thus this article deals with different kinds of chemical reactions; enantioselective reductions; heterogenized transition metal complexes; modified metal catalysts (nickel, platinum, and palladium); diastereoselective reactions; reactions of achiral compounds; and reactions of chiral compounds.
The article mainly concerns the issue of that “Liquid phase catalytic hydrogenation became in the last hundred years a beneficial method among organic chemical processes, applied both in laboratory and in industry” (Tungler 224). According to the information stated in the article there were a great number of different attempts within the competition “between homogeneous and heterogeneous catalytic asymmetric hydrogenation” which began nearly in the second half of the twentieth century (Tungler 224).
The competition is considered to be unequal because in spite of the awareness of the advantages and drawbacks of both approaches of the scientists and people taking part in the experiments and concerning the sphere of organic chemistry, it obvious that the heterogeneous catalytic reactions can be practically used. The issue is researched by a great number of scientists from different institution presenting diverse scientific value; they use modern and the most sophisticated techniques and methods in order to investigate the issue of “surface phenomena during asymmetric hydrogenations” (Tungler 225).
From the point of view of use of the results of reactions in the sphere of synthetic matters the article gives a full description and discusses the heterogenized transition metal complexes together with the modified metal catalysts. There are two basic methods of heterogenization; they are phase variation and anchoring.
“During anchoring the catalyst is bound by chemical methods to the surface of a support matrix, in phase variation the catalyst is dissolved in water, in a fluorinated solvent or in non-aqueous ionic liquid, which can be separated from the solvent containing the substrate and the product” (Tungler 225). Further the article describes the biphasic catalysis, the reaction and its result; the use of water-soluble ligands and other examples of catalysis conducted with the utilization of water as one of the components of the reaction.
Then the author of the article finds necessary to enumerate types of fixations (entrapping in spongy materials, covalent bonding, and ionic bonding) and types of supports that can be possibly represented by inorganic materials and polymers. The further issue concerning the modified metal catalysts also deals with asymmetric heterogeneous catalysts, and “the combination of the catalytically active metal and the modifier ensures the enantioselectivity only at a small group of substrates” (Tungler 226).
The successive passages give a specified description of different types of catalysts. Thus the nickel catalysts are very simple from the point of view of preparation for the not very complicated process of the reaction. Further there comes a scheme of hydrogenation of various ketones with cinchona modified catalyst; and palladium catalysts.
The next part of the article gives a description of diastereoselective reactions: reactions of achiral starting compounds and reactions of chiral compounds. The author explains the value of the hydrogenation of thymol from the point of view of industrial application. Further comes the significant summary of results of the hydrogenation of thymol, which represents a great value from the point of view of menthol production, whereas menthol was “extracted from natural mint containing oils” (Tungler 233). The next come the description of the reactions of chiral starting compounds, which claims that the “frequently used method for diastereoselective hydrogenation is the reduction of molecules having a chiral moiety and a prochiral unsaturated part” (Tungler 234).
Thus the article “Asymmetric heterogeneous catalytic hydrogenation; is it a useful tool for the synthetic organic chemist?” from the ARKIVOC journal, written by Antal Tungler deals with specific reactions researched at the Department of Chemical Technology within the Budapest University of Technology and Economics in order to find out the possibility of the industrial utilization of the results of different experiments; one of the examples was the industrial production of menthol with the help of hydrogenation of thymol. The experiments involved the asymmetric hydrogenation using different kinds of catalysts, such as nickel, platinum, and palladium; diverse types of fixations (entrapping in spongy materials, covalent bonding, and ionic bonding); and different types of supports that can be possibly represented by inorganic materials and polymers in order to achieve specific results. The article is closely connected with the issue of organic chemistry described in the news, namely the problem concerning heterogeneous catalytic hydrogenation.
Works Cited
Tungler, Antal, and Eva Sipos, and Viktor Hada. “Asymmetric Heterogeneous Catalytic Hydrogenation; is it a Useful Tool for the Synthetic Organic Chemist?” ARKIVOC VII (2004): 223-242. Web.