High energy irradiation

Excited states of hydrocarbon molecules often undergo nondissociative transformation, although dissociative transformation is not unknown. In the liquid phase, these excited states are either formed directly or, more often, indirectly by electron-ion or ion-ion recombination. In the latter case, the ultimate fate (e.g., light emission) will be delayed, which offers an experimental window for discrimination. A similar situation exists in liquid argon (and probably other liquefied rare gases), where it has been estimated that -20% of the excitons obtained under high-energy irradiation are formed directly and the rest by recombination (Kubota et al., 1976). 

The kinetics of electron-ion recombination is well described by the diffusion model both for photoionization and for ionization induced by high-energy irradiation. 

The mean thermalization length in high-energy irradiation tends to be somewhat longer than in the photoionization case, possibly due to higher initial energy. 

High-energy irradiation, silicone network preparation via, 22 567 High energy ruminant feeds, 10 864-865 High enriched uranium (HEU), 17 526 Higher aliphatic alcohols aldol process, 2 41-43 analysis, 2 9-10, lOt chemical reactions, 2 4-6 economic aspects, 2 7-9 health and safety factor, 2 6 manufacture from fats and oils, 2 12-19 oxo process (odd-numbered alcohols), 2 1, 10, 36-41... 

The investigation of free radicals formed by high energy irradiation of polytetrafluoroethylene is an example of an early application of EPR to polymer radicals. 

Early Events in High-Energy Irradiation of Polymers... 

One approach could be the attempt to include the lipids into the stabilization process. Lipid molecules bearing polymerizable groups can actually be arranged as planar monolayers or as spherical vesicles and polymerized by high energy irradiation within these membrane like structures under retention of the orientation of the molecules (8,9,36). 

Dajka, K Takacs, E Solpan, D Wojnarovits, L Guven, O. High-energy irradiation treatment of aqueous solutions of C.l. Reactive Black 5 azo dye pulse radiolysis experiments. Radiation Physics and Chemistry, 2003 67, 535-538. 

High-energy irradiation of the lower alcohols gives solvated electrons, solvated protons and radicals [64]. Solvated electrons are also obtained by irradiation of the aprotic amide solvents [65] frequently used in organic electrochemistry and by the irradiation of hexamethylphosphoric triamide [66], N-Methylpyrrolidone which has properties similar to dimethylformaraide, is a useful solvent for the generation of solvated electrons because the reaction between electrons and protons is relatively slower than with dimethylformamide [67],... 

Rate constants in excess of 10 M s are determined by pulse-radiolysis methods [4, 5]. High-energy irradiation of a solution containing the substrate and an excess of the aromatic species, generates the aromatic radical-anion. The decay of this by electron transfer to the substrate is followed using uv-spectroscopy and affords a rate constant for the second-order process. Slow rates of electron transfer are determined by adding the substrate to a solution of the aromatic radical-anion and following the reaction by conventional methods. 

Note 1 Peroxidation, ozonolysis, high-energy irradiation, and plasma etching are methods of generating active sites on a polymer surface. 

Polytetrafluoroethylene Degradation into low-molecular-weight products ("micropowders") used as additives to coatings, lubricants, and inks High-energy irradiation at 200-400 kGy... 

There is still some doubt as to the validity of the assignments of the ESR spectra for high energy-irradiated polypropylene. It is difficult for us to evaluate the probability of the different interpretations, even though these problems have been treated previously in this laboratory (50). 

Poly(1-butene). Loy (31) reported that the spectrum of high energy-irradiated poly(1-butene) at — 190°C. gave a poorly resolved six-line spectrum, with a hyperfine splitting constant of 21 gauss, indicating that the radicals formed have the structure (XVI) ... 

Poly (4-methyl-1-pentene). Poly(4-methyl-l-pentene) has not yet drawn much attention in radiation chemistry. As far as we know, only one study on high energy-irradiated poly(4-methyl-l-pentene) has been published (25), and this was in the form of a short communication. The ESR spectrum at liquid nitrogen temperature was a sextet with a hyper-fine splitting constant of 23 gauss. The radicals producing this spectrum were supposed to have structure XXI—i.e., radicals formed by side-chain scission. 

Knowledge of the effect of high-energy irradiation on nucleate boiling is not available. Sueh information is necessary for the design of boiling-... 

In both light and high energy irradiation induced reactions, phenyl-thiol, 2-mercaptomesitylene, and their sulfides inhibit nonchain processes,201202 e.g., the light-induced conversion of benzophenone in 2-propanol to benzopinacol and acetone.99 217 The reaction converts compounds into radicals by removal or addition of hydrogen atoms. The sulfur compounds in rapid hydrogen transfer processes convert the free radicals to stable molecules and may do so repeatedly.46 46... 

The generation of active centers on powdered polyamide backbone by high energy irradiation or by chemical reactions is reported in the literature. 

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