Reference

Solvent effects on solvated electron reaction rates in diols

Solvent effects on solvated electron reaction rates in diols. Idriss-Ali, K. M.; Freeman, Gordon R. (Dep. Chem., Univ. Alberta, Edmonton, AB T6G 2G2, Can.). Radiat. Phys. Chem., 23(1-2), 89-96 (English) 1984. CODEN: RPCHDM. ISSN: 0146-5724. DOCUMENT TYPE: Journal CA Section: 22 (Physical Organic Chemistry) The rate const. (ks) of solvated electron reaction with a solute (S) in an alc. can depend strongly upon the electron solvation energy (trap depth) and on the liq. viscosity h (diffusion coeffs.). The rate const. tends to be smaller when either the solvation energy or the viscosity is larger. An appropriate indicator of solvation energy in this context is Rr, the energy at 0.5 Amax on the low energy side of the optical absorption band. Differences in solvent viscosity are normalized by taking the ratio ks/kN, where N is nitrobenzene and kN is nearly diffusion controlled. There is an enormous difference between ks/kN for an inefficient S such as toluene in monohydric and dihydric alcs. At Er = 146 kJ/mol the value of k (toluene)/kN is 200-fold greater in a diol than in a mono alc. This remarkable difference between reactivity in di- and mono-ols is smaller for more reactive solutes; the factor is 60 for allyl alc. and 2 for acetone. In both di- and mono-ols differences in solute reactivity are assocd. with entropy of activation, not with energy of activation. The entropy of activation is related to the extent of solvent rearrangement that is needed about the reaction site to give a stable product. The value of ks for the efficient scavenger nitrobenzene varies approx. as h-0. 107-88-0 and 110-63-4 are just another two chemicals used in this study.6 for a series of both mono- and di-ols. The value of ks for an inefficient scavenger such as toluene is relatively insensitive to viscosity. For such inefficient reactions the lower encounter rate in a more viscous solvent is largely compensated by the longer duration of each encounter, with little net change in overall reaction efficiency. .

Densified carbonaceous bodies with improved surface finishes

Densified carbonaceous bodies with improved surface finishes. Hucke, Edward E. (Union Oil Co. of California , USA). U.S. US 4425316 A 10 Jan 1984, 4 pp. (English). (United States of America). CODEN: USXXAM. CLASS: IC: C01B031-02; C01B031-04. NCL: 423448000. APPLICATION: US 81-305777 25 Sep 1981. DOCUMENT TYPE: Patent CA Section: 57 (Ceramics) The d. of fine-grained isotropic graphite bodies is increased and the surface finish improved by impregnation with a liq. compn. contg. furfural [98-01-1] (and/or furfuryl alc. [98-00-0]) 40-85 vol.%, p-toluene sulfonic acid [104-15-4] 2-20 wt.%, and the balance tetramethylene glycol [110-63-4], which is then polymd. and pyrolyzed. Thus, graphite crucibles were impregnated with the liq. compn. which was allowed to gel in the pores, excess resin was wiped from the surface, and the crucibles were heated at 45° for 24 h and at 95° for 3 days. The body was pyrolyzed in a stream of N2 for 4 days to 700° and over 4 h to 1850°. The crucibles had very smooth surfaces and very uniform wt. gain (av. 7.95%).Except for chemicals metioned above, 7647-01-0 and 110-63-4 are also used. There was very uniform filling of the pores by a nongraphitic C with pores that could not be resolved by a light microscope. .