Detail of "7699-00-5"

Reference

Enantioselective hydrogenation in supercritical fluids

Enantioselective hydrogenation in supercritical fluids. Limitations of the use of supercritical CO2. Minder, B.; Mallat, T.; Baiker, A. (Department of Chemical Engineering and Industrial Chemistry, Zurich CH-8092, Switz. 7699-00-5 and 7440-06-4 are cas registry numbers. These chemicals are also mentioned in this article.). Process Technology Proceedings, 12(High Pressure Chemical Engineering), 139-144 (English) 1996 Elsevier. CODEN: PTPREM. ISSN: 0921-8610. DOCUMENT TYPE: Journal CA Section: 45 (Industrial Organic Chemicals, Leather, Fats, and Waxes) The Pt-catalyzed enantioselective hydrogenation of Et pyruvate to (R)-Et lactate was considerably faster (by a factor of 3-3.5) in supercrit. ethane than in the conventional apolar solvent toluene, whereas the enantioselectivity was unaffected. Complete catalyst deactivation was obsd. in CO2, which was shown by FTIR to be due to the redn. of CO2 to CO via reverse water gas shift reaction. The catalyst could be regenerated by exposing it to ambient air, while H treatment was less efficient. This is the first evidence to the limitation of catalytic hydrogenations over Pt metals in supercrit. CO2. .

Heterogeneous asymmetric reactions

Heterogeneous asymmetric reactions. Part 40. New data on repeated use of Pt-alumina catalyst during enantioselective hydrogenation of ethyl pyruvate. Balazsik, Katalin; Bartok, Mihaly (Organic Catalysis Research Group of the Hungarian Academy of Sciences, Szeged H-6720, Hung.). Journal of Molecular Catalysis A: Chemical, 219(2), 383-389 (English) 2004 Elsevier B.V. CODEN: JMCCF2. ISSN: 1381-1169. DOCUMENT TYPE: Journal CA Section: 23 (Aliphatic Compounds) The repeated use of Pt-alumina (E4759) catalyst modified by dihydrocinchonidine (DHCD) was studied in the enantioselective hydrogenation of Et pyruvate under mild exptl. conditions not studied before (hydrogen pressure: 1 bar, temp. 1344-28-1 and 7699-00-5 which are cas registry numbers are also used here.: 253-298 K, DHCD concn.: 0.001-0.1 mmol/l) in toluene and AcOH. The effects of different reuse methods, DHCD concn. and temp. on the conversion and enantiomeric excess were studied. In toluene depending on the reaction conditions an increase in ee on reuse of 10-20% was obsd. This effect was not found in AcOH medium. It appears that the phenomenon is an intrinsic feature of the Pt-alumina-cinchona catalyst system, in which the restructuring of the catalyst Pt surface may play an important role. .