Oxygenated solvent

Section 15 14 The hydroxyl group of an alcohol has its O—H and C—O stretching vibrations at 3200-3650 and 1025-1200 cm respectively The chemical shift of the proton of an O—H group is variable (8 1-5) and depends on concentration temperature and solvent Oxygen deshields both the proton and the carbon of an H—C—O unit Typical... 

H. T. Kohlbrand, Case History of a Deflagration Involving an Organic Solvent/Oxygen System Below its Flash Point, Paper presented at AlChE Loss Prevention Symposium, San Diego, Aug. 1990. 

Benzoyl hydroperoxide was used for the conversion of divinyl sulphide into divinyl sulphoxide by Levin as early as 1930. In 1954 Bateman and Hargrave reported that saturated sulphides may be oxidized to sulphoxides by means of cyclohexyl or t-butyl hydroperoxide. These authors found that in both polar and non-polar solvents oxygen transfer occurred to give quantitative yields of sulphoxides over a wide range of experimental conditions according to equation 7. It was also reported that a quantitative yield of sulphoxides was obtained from the reaction of unsaturated sulphides with t-butyl and cyclohexyl hydroperoxides in methanol. With t-butyl hydroperoxide in benzene the sulphoxide yield was in no case stoichiometric, varying from 90 to 5% under the condition chosen. 

Meanwhile attempts to find an air oxidation route directly from p-xylene to terephthalic acid (TA) continued to founder on the relatively high resistance to oxidation of the /Moluic acid which was first formed. This hurdle was overcome by the discovery of bromide-controlled air oxidation in 1955 by the Mid-Century Corporation [42, 43] and ICI, with the same patent application date. The Mid-Century process was bought and developed by Standard Oil of Indiana (Amoco), with some input from ICI. The process adopted used acetic acid as solvent, oxygen as oxidant, a temperature of about 200 °C, and a combination of cobalt, manganese and bromide ions as catalyst. Amoco also incorporated a purification of the TA by recrystallisation, with simultaneous catalytic hydrogenation of impurities, from water at about 250 °C [44], This process allowed development of a route to polyester from purified terephthalic acid (PTA) by direct esterification, which has since become more widely used than the process using DMT. 

Fig. 13. Coordination fluctuations of Nb5+ in the decaniobate ion during a molecular dynamics calculation of the decaniobate ion in continuum solvent. Oxygen atoms are red, and niobium atoms are green. The dynamics are characterized by frequent Nb— i.3-0 bond ruptures, as shown in (b), followed by instantaneous tetrahedral coordination for the Nb3, shown in (c). See Figure 4 for description of notation.

Supercritical water is neither a liquid nor a gas, but it has properties between the liquid and gas phases (i.e., density approaching its liquid phase and diffusivity and viscosity approaching its gas phase). At the critical point, hydrogen bonds disappear, and water becomes similar to a moderately polar solvent. Oxygen and almost all hydrocarbons become completely miscible... 

Dioxygenyl tetrafluoroborate Organic materials Nitric acid Hydrocarbons Nitryl perchlorate Organic solvents Oxygen (Liquid) Hydrocarbons Ozone Aromatic compounds, or Benzene, etc. Ozone Aromatic compounds, or Benzene, etc. Permanganic acid Organic materials Peroxodisulfuric acid Organic liquids Peroxomonosulfuric acid Aromatic compounds Silver perchlorate... 

Guaiacoxyacetoveratrone. Unusual Effects of Solvent, Oxygen and Singlet State Participation", Can. J. Chem., 1991, 69, 104. 

Irradiation of bromothiazoles in various organic solvents (methanol, ether, cyclohexane) produces thiazole (and the isomeric isothiazole) as the main reaction product386. The reactivity decreases in the order 2-bromothiazole > 5-bromothiazole 4-bromoth-iazole, and is probably related to the C—Br bond strengths. The mechanism is considered to involve homolytic cleavage of the C—Br bond, followed by abstraction of a hydrogen atom from the solvent. Oxygen does not exhibit any noticeable effect upon the reaction, but the debromination is accelerated by triethylamine. 

Tiibing Type Acids (weak) Acids (strong) Bases (weak) Bases (strong) Vi as o Organic solvents Oxygen Salt Solutions... 

The following results in the case of solvation of poly(vinyl alcohol) (PVA) in water, ethanol, and water-ethanol mixtures show that the situation in the case of solvation of polar polymers in polar solvents is different from the above case of the solvation of nonpolar polymers in nonpolar solvents. Shown in Figure 11-10 is the distribution of solvent oxygen and carbon atoms around the PVA oxygen (OPVA) calculated by Miiller-Plathe and van Gunsteren [79], In all solvents the first peak in the RDF is at... 

Figure 11-10 Solvation of the oxygen atoms of poly(vinyl alcohol), (a) Partial radial distribution functions of PVA oxygen with solvent oxygen and (b) solvent carbon atoms. The figure is taken from Miiller-Plathe and van Gunsteren [79]...

The Hamiltonian for the vibration of a tagged (solute) oxygen molecule is taken to be harmonic, as in Equation (22). The bath Hamiltonian involves the translations and rotations of all (solute and solvent) oxygen molecules (4) ... 

Gordon and Taube (17) have shown that the slow U02 " -solvent oxygen exchange is catalyzed by U (V). 

In divided cells the reaction at the counterelectrode is seldom a problem in aqueous solvents, oxygen evolution at the anode is convenient if chloride is desired as the anion, it is advisable to add ethanol to the anodic compartment as it reacts with the evolved chlorine. In oxidations, hydrogen evolution is a convenient counterelectrode reaction it may also be used in nonaqueous solvents [68-73]. In methylene chloride it has been noted that chloride ion formed by reduction of methylene chloride at the counterelectrode could diffuse to the anode compartment and participate in the follow-up reactions [426] this can be avoided by adding a little acetic acid to the cathode compartment. 

The evidence for carbocation intermediates in the pinacol rearrangement is compelling for some substrates and conditions. Bunton" found that pinacol itself that was recovered from O-enriched aqueous sulfuric acid had incorporated an appreciable amount of solvent oxygen. Under these conditions the reaction goes to completion, i.e. the incorporation cannot be due to reversible formation of diol from pina-... 

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