Short contact time dissolution of vitrinite and inertinite concentrates

The short contact time dissolution of vitrinite and inertinite concentrates of an Australian bituminous coal was studied under isothermal conditions with tetralin as solvent. The reactivity of the two maceral types and the yields and nature of the products were determined for a range of reaction temperatures (400, 420 and 440 °C) and reaction times (2–20 min). The dissolution of vitrinite proceeded at a significantly greater rate than for inertinite and was associated with greater selectivity to soluble non-gaseous products. At very short reaction times (2 min), the vitrinite underwent solubilizing reactions to yield products of higher molecular weight and greater oxygen functionality than was the case for inertinite, for which changes in the chemical nature of the products were negligible over the range of conditions studied. At longer reaction times (5 min), the composition of the vitrinite-derived products was similar to that of the inertinite-derived products.     

Summary of discussion on ‘Sciences related to pitch and coke usage in carbon manufacture’

This article is a brief summary of the Discussion session held after the presentation of the preceding papers at the conference organized by the Industrial Carbon and Graphite Group of the Society of Chemical Industry, London, March 1984.     

Coal liquefaction using a hydrogenated creosote oil solvent: H-atom transfer from hydrogen donor components in the solvent

The presence of hydroaromatic, hydrogen donor components in a coal-derived solvent is one of the more important factors in the successful operation of a non-catalytic coal liquefaction process. Various hydrogen donor species present in a hydrogenated creosote oil have been identified. Their rate of disappearance under conditions that are consistent with a short residence time coal liquefaction process has been used to rank the reactivities of the various hydrogen donors. 1,2,3,10b-Tetrahydrofluoranthene was found to be an exceptional donor while 4,5-dihydropyrene, the hexahydropyrenes and 9,10-dihydrophenanthrene were found to be quite active. Sym.-octahydrophenanthrene and 2a,3,4,5-tetrahydroacenaphthene exhibited moderate activity. Tetralin and the four methyltetralin isomers were found to be unreactive under the coal liquefaction conditions employed.     

Analysis of polar compound classes in SRC-II liquids: Comparison of non-aqueous titrametric,i.r. spectrometric and h.p.l.c. methods

Results for various types of polar compounds in SRC-11 coal-derived liquids and other fuels were obtained by one or more of the three analytical methods: non-aqueous titration, i.r. spectroscopy and h.p.l.c. Practical aspects as well as precision, accuracy and assumptions necessary for effective application of each of the methods are discussed. H.p.l.c. is applicable to the widest variety of compound types, is the most rapid, most sensitive and shows the best promise for increased development and improvement. Application and development of these techniques is a logical step toward improving process monitoring, catalyst development, toxicological screening and general fuel analysis.     

Effect of catalysts on the reaction between a cycloaliphatic diisocyanate (H-MDI) and n-butanol

Kinetics of the reaction between bis(4-isocyanatocyclohexyl)methane, H-MDI, and n-butanol was studied in toluene at 100°C. Effects of various catalysts, such as Hg(CH₃COO)₂, Zn(CH₃COO)₂ · 2H₂O, SnCl₄ · 5H₂O, and dibutyltindilaurate on the reaction rate and kinetics were also investigated. Reactions were followed by determining the unreacted isocyanate as a function of reaction time, using the standard dibutylamine back titration method. All catalysts seem to be very effective in increasing of the rate of the reaction compared to the uncatalyzed system. Depending on the initial stoichiometric ratio of (NCO) and (OH) and the concentration of the catalyst used, it seems possible to have preferential catalysis of the primary reaction between (NCO) and (OH) over the side reactions.     

Graft copolymerization onto rubber. VII. Graft copolymerization of methyl methacrylate onto rubber using potassium peroxydisulfate catalyzed by silver ion

The graft copolymerization of methyl methacrylate onto natural rubber (NR) was carried out varying the concentration of monomer, initiator, thiourea, and silver nitrate over a wide range. The grafting reaction was temperature-dependent. From the Arrhenius plot, the overall energy of activation was computed. A suitable reaction scheme and rate expression for the rate of polymerization was suggested.     

Formation and Properties of Calcium Aluminosilicate Glasses

The glass-forming region for calcium aluminosilicate glasses has been determined. A number of properties of these glasses (thermal expansion coefficient, glass transformation and dilatometric softening temperature, and refractive index) have been studied. The results of these measurements suggeq that the structures of these glasses may not as closely resemble those of alkali aluminosilicate glasses as is commonly assumed. Evidence is presented which suggests that the binary calcium aluminate glasses may be phase separated.     

Phase Studies Concerning Sintering in Aluminas Doped with Ti4+

Previous solid state analyses of sintering in Ti⁴⁺-doped-commercial alumina are shown to be in error because a liquid phase exists in the appropriate region of the Al₂O₃−TiO₃−Na₂Ophase diagram at least by 1350^°C, a temperature lower than that at which "solid state" studies were conducted. It is suggested that liquid-phase sintering is a much more common occurrence than was realized formerly.     

Physical and chemical characteristics of butterfat fractions obtained by crystallization from molten fat

Both summer and winter butterfats were fractionated using a laboratory procedure which was designed to simulate a commercial fractionation process. The process is based on a slow, controlled cooling of the melted fat, a short stabilization time at the fractionation temperature, and separation of the crystals from the liquid oil by vacuum filtration using a stainless steel perforated disc. Fractionation temperatures of 29, 26, 23 and 19 C for winter butterfat and 29 and 19 C for summer butterfat were used to obtain solid and liquid fractions at each temperature. Three replications at each temperature showed good reproducibility of results. The fractions were characterized by their fatty acid and triglyceride compositions, melting and crystallization behavior, iodine value, peroxide value and melting point. Presented at the AOCS meeting in Philadelphia in May 1985.     

Decision rules for selecting effect sizes in meta-analysis: A review and reanalysis of psychotherapy outcome studies.

This study deals with some of the judgmental factors involved in selecting effect sizes from within the studies that enter a meta-analysis. Particular attention is paid to the conceptual redundancy rule that Smith, Glass, and Miller (1980) used in their study of the effectiveness of psychotherapy for deciding which effect sizes should and should not be counted in determining an overall effect size. Data from a random sample of 25 studies from Smith et al.'s (1980) population of psychotherapy outcome studies were first recoded and then reanalyzed meta-analytically. Using the conceptual redundancy rule, three coders independently coded effect sizes and identified more than twice as many of them per study as did Smith et al. Moreover, the treatment effect estimates associated with this larger sample of effects ranged between .30 and .50, about half the size claimed by Smith et al. Analyses of other rules for selecting effect sizes showed that average effect estimates also varied with these rules. Such results indicate that the average effect estimates derived from meta-analyses may depend heavily on judgmental factors that enter into how effect sizes are selected within each of the individual studies considered relevant to a meta-analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)