Atomic reaction with

The 0 -phenyl-0 -piperidyl-(2)-acetic acid methylester of BP 135° to 137°C under 0.6 mm pressure is obtained in theoretical yield by hydrogenation of 50 g of 0 -phenyl-0 -pyridyl-(2)-acetic acid methylester in glacial acetic acid in the presence of 1 g of platinum catalyst at room temperature, while taking up 6 hydrogen atoms. Reaction with HCI gives the hydrochloride. Resolution of stereoisomers is described in U.S. Patent 2,957,880. 

Leger, L. Oxygen Atom Reaction with Space Shuttle Materials at Orbital Altitudes, NASA Technical Memorandum 58246, May 1982... 

Cobalt atom reactions with ethylene were also studied (121). By using techniques similar to those described for Cu (122) and Ni (101), it has proved possible to synthesize a novel series of mononuclear and binuclear cobalt-ethylene complexes, Co(C2H4) , = 1, or 2, and... 

Fig, 37. Far-infrared spectra of chromium, iron, and cobalt atom reactions with benzene, benzene-(f and benzene/benzene-d mixtures in argon matrices at 10-12K 171). 

To conclude, we shall mention some metal-atom reactions with boranes (172) and carboranes (173). When cobalt atoms reacted with pentaboraneO) and cyclopentadiene, a number of new metalloborane clusters were formed (172), two of which were 65115003(17-05115)3 and cyclopentyl-B5H40o2(i7-05H5)3. Possible structures for the former are shown in Fig. 42. The reaction of cyclopentadiene, pentaboraneO), and 2-butyne with cobalt atoms yielded the metallocarborane species illustrated in Fig. 43 (173). 

An overview of the time-dependent wavepacket propagation approach for four-atom reactions together with the construction of ab initio potential energy surfaces sufficiently accurate for quantum dynamics calculations has been presented. Today, we are able to perform the full-dimensional (six degrees-of-freedom) quantum dynamics calculations for four-atom reactions. With the most accurate YZCL2 surface for the benchmark four-atom reaction H2 + OH <-> H+H2O and its isotopic analogs, we were able to show the following ... 

Aspects of the apparatus for the synthesis using metal atoms are described. The reactions of the atoms of rhenium, tungsten, and osmium with hydrocarbons including alkanes are described. It is shown that metal atom reactions with alkanes can give isolable organometallic compounds including l-alkylidene compounds. 

For over 15 years we have conducted research utilizing metal atoms in low temperature spectroscopic and synthetic studies at Rice University.8 Our synthetic work was started in the late 1960s with the work of Krishnan, on lithium atom reactions with carbon monoxide, extended by Meier- in his studies of lithium atom reactions with water and ammonia and expanded over the next several years to include metal atom interactions with HF, H2O, H3N, H4C, and their hundreds of organic analogs—RF, R2O, ROH, R3N,. . . H3N, R4C, R3CH, etc. A most exciting aspect of... 

Kanofsky, J. R., and D. Gutman. Direct observation of the products produced by the 0-atom reactions with ethylene and propylene studied in high-intensity molecular beams. Chem. Phys. Lett. 15 236-239. 1972. 

Figure 11. Mechanism for F-atom reaction with a silicon film leading to the products Sip2 and Sip4.

Chlorine atoms react with aromatic hydrocarbons, but only at a significant rate with those having saturated side chains from which the chlorine atom can abstract a hydrogen or unsaturated side chains to which it can add. For example, the rate constant for the Cl atom reaction with benzene is 1.3 X 10"15 enr3 molecule-1 s-1 (Shi and Bernhard, 1997). On the other hand, the rate constants for the reactions with toluene and p-xylene are 0.59 X 10-10 and 1.5 X 10-l() enr3 molecule"1 s"1, respectively (Shi and Bernhard, 1997), and that for reaction with p-cymene is 2.1 X 10"10 cm3 molecule"1 s-1 (Finlayson-Pitts et al., 1999). Hence... 

Shi, J. C., and M. J. Bernhard, Kinetic Studies of Cl-Atom Reactions with Selected Aromatic Compounds Using the Photochemical Reaction-FTIR Spectroscopy Technique, hit, J. Chem. Kinet, 29, 349-358 (1997). 

Because many of the alternates and replacements for CFCs have an abstractable hydrogen atom, reaction with OH in the troposphere dominates their loss. Table 13.4 gives some rate constants for the reaction of OH with these compounds the kinetics summary of De-More et al. (1997) should be consulted for other compounds. It is seen that the rate constants at 298 K are typically in the range of 10-l3-10-ls cm3 molecule-1 s-1, depending on the degree of halogen substitution and the nature of the halogen, e.g., F, Cl, or Br. Typical A factors are of the order of 1 X 10 12 cm3 molecule-1 s-1 per H atom (DeMore, 1996). 

The electronic energy of the iodine atom in the 52Py2 state renders a number of atomic reactions with halogen and interhalogen molecules exothermic which would be endothermic for the analogous reactions of the ground state. 

Selective denitration of methyl 4,6-O-benzylidene- and 4,6-O-alkyl-idene-D-hexopyranoside 2,3-dinitrates to yield 3-nitrates has also been achieved by using sodium nitrite in ethanol as the reagent.233,238, 241.242 interestingly, when the nitrate group is on a primary carbon atom, reaction with this reagent takes place to give the primary alcohol,232,241,243 but the conversion may, on occasion, proceed only with... 

First experiments on oxygen atom reactions with hydrocarbons, with the zone of discharge in water vapor, as well as in O2, used as a source of 0 atoms, have shown that the reaction products are formaldehyde, acetaldehyde, acids, alcohols, peroxides, i.e., products of lower degrees of conversion than that yielding H20, CO, and C02. 

Thus, CH20 and CO are obtained in equal amounts. Other reactions of a lower probability are the formation of alcohol by reaction 0 + C2H6 - C2H6OH, possibly depending on pressure, and the formation of acetaldehyde 0 + C2H6 - C2H 0 + H2. It will be noted that the formation of alcohol was observed by Murad and Noyes63 in the course of oxygen atom reactions with ethane. 

It follows that oxygen atom reactions with saturated and unsaturated hydrocarbons proceed with scission of the C—C and C=C bonds, respectively. 

Cvetanovic67 was concerned with oxygen atom reactions with unsaturated hydrocarbons. The oxygen atoms were obtained in his experiments by mercury-photosensitized decomposition of N20. Cvetanovi6 came to the conclusion that the reaction of oxygen atoms with ethylene proceeded essentially with scission of the hydrocarbon bond, while with higher olefins this was not observed. Corresponding oxides (epoxides) and carbonyl compounds were formed in the course of the reaction. 

This reaction is similar to the step observed in O atom reactions with ethane. 

Great attention was paid to oxygen atom reactions with acetaldehyde. It will be mentioned that the study of this reaction encountered greater difficulties. 

In investigating the oxygen atom reaction with carbon monoxide 1 62 it was found that this reaction at pressures of 2.5 mm. Hg and higher obeyed essentially a bimolecular law, although a slow trimolecular reaction might have occurred as well. 

Relative concentrations of oxygen atoms were determined from the limiting amount of a primary or a secondary product (or the sum of these) in O atom reactions with the substance studied. The reactant was admitted in sufficient concentrations at various sites of the reaction vessel, and the limiting amount of reaction products was determined. A curve plotted as log (O)0/(O)r vs. X was used for determining the rate constant for the disappearance of atoms. 

Cvetanovi6,0>71 determined the relative rate constants of oxygen atom reactions with various molecules. 

Rate Constants for Oxygen-Atom Reactions with Various Molecules... 

Substantial production of Hg(3P0) atoms has been seen by Callear and McGurk (180). Continuous emissions that presumably originate from loose complexes between the Hg(3P0) atoms and the hydrocarbons have been observed near 2537 A (938). No HgH has been detected from the (3Pi) atom reactions with saturated hydrocarbons (177). 

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