Influence of alkali on the carbonization process—II: Carbonization of various coals and asphalt with NaOH

Four kinds of coal, one weathered coal and one petroleum asphalt, were carbonized with 120 wt% NaOH. With the addition of NaOH, the amount of hydrogen evolved increases enormously and the temperature of its evolution is lowered by 200–300°C. The reaction is thought to be a dehydrogenation resulting from the addition of NaO- to the active methylene groups or to aromatic nuclei, followed by liberation of NaOH, and causing some condensation reactions. At a higher temperature a large amount of CO evolves. This evolution is due to a reduction of Na₂O or Na₂CO₃ produced in an earlier step of the reaction, with residual carbon.     

Influence of alkali on the carbonization process—III: Dependence on type of alkali and of alkali earth compounds

3,5-Dimethylphenol-formaldehyde resin was carbonized up to 1000°C with various kinds of alkali and alkali earth compounds added. The hydroxides of Li, Na, K, Sr and Ba reacted with the resin to produce large amounts of hydrogen and CO. The order of reactivity was, Li <K <Na and Ca, Mg ? Sr <Ba. Carbonates evolve only a small amount of hydrogen, although evolution of CO was very large. Carbonates cannot react with reactive methylene groups or aromatic hydrogens, whereas hydroxides easily substitute these hydrogens with MO-, liberating hydrogen atoms. The reduction of carbonate with carbon takes place in a similar way as that with hydroxides. The lower the melting point of the alkali or alkali earth compounds is, the lower the temperature of evolution of hydrogen is. This may be due to the good wettability of lower melting alkali or alkali earth compounds.     

Vinyl polymerization, 399. Polymerization of methyl methacrylate with sodium polystyrenesulfonate in presence of polyethyleneglycol

The effect of polyethyleneglycol on the radical polymerization of methyl methacrylate initiated with an aqueous solution of sodium polystyrenesulfonate was studied. Under the definite condition, the conversion of methyl methacrylate raised from 6.6 to 100% by the addition of polyethyleneglycol. It was concluded that polyethyleneglycol acted only as a host of Na⁺, but not as a phase transfer catalyst.     

Low temperature—long time,high temperature-short time liquefaction of coal: The Hokudai process

A Japanese cola was hydrogenated in wash oil with fine iron dust and sulphur as catalyst under a reaction pressure of 12–13 MPa at 420 °C for 2 h and then at 500 °C for 0–20 min. The liquid yield boiling up to 600 °C amounted to 55–66 wt%. Pyridine conversion was ≈ 100 wt%, benzene conversion 82–90 wt% and n-hexane conversion 53–70 wt%. Compared with direct hydrogenation at 500 °C for 10 min the low temperature-long time plus high temperature-short time liquefaction process (the Hokudai process) is a very effective method for obtaining high liquid yield under relatively low hydrogen pressure without coking, using disposable catalyst and non-donor solvent.     

The origins of defects in sputtered Co-Cr perpendicular magneticrecording media

The authors examine various causes of contamination and the defects they produce, and they typify some defects that originate at the metal/substrate interface, as nodules or extraordinary particles. They find that these are not caused by dirt or mishandling, but are induced by an exudate from the polymide substrates used. The nodules' characteristic acorn shape can be analyzed mathematically to suggest a possible exudate-induced mechanism for their formation and growth. The authors conclude that most of these defects can be eliminated     

Influence of Thermo-mechanical Control Process for Duplex Stainless Steel on Low-Temperature Toughness

Metallurgical and Materials Transactions A - The microstructure dependence of the low-temperature toughness of a 2205 duplex stainless steel produced by a thermo-mechanical control process was...     

Vinyl polymerization: 414. Polymerization of vinyl monomer initiated by poly(N,N,N-trimethyl-N-2-methacryloxyethyl)ammonium chloride

The polymerization of vinyl monomer initiated by an aqueous solution of poly(N,N,N-trimethyl-N-2-methacryloxyethyl)ammonium chloride (poly(Q-DMAEM-CI) has been carried out at 85°C. The effects of the amounts of vinyl monomer, poly(Q-DMAEM-CI) and water on the conversion of vinyl monomer have been studied. The overall activation energy in the polymerization of MMA is estimated as 41.9 kJ mol^?1. The polymerization proceeds through a radical mechanism. The location in which the polymerization occurs is discussed. The selectivity for vinyl monomer is explained by ‘the concept of hard and soft hydrophobic areas and monomers’.     

Coking reaction in hydrogenation

Asphaltene prepared from a Japanese coal (Akabira, 81.2 wt% C) and coal tar pitch were heat treated under nitrogen or hydrogen. Under nitrogen the initial thermal decomposition produced radicals which abstracted hydrogen from other molecules to stabilize and to produce smaller molecules and gas. The molecules from which hydrogen was abstracted as well as other radicals polycondensed to produce heavier solvent-insoluble fractions. Under hydrogen the radicals were stabilized by hydrogen gas to produce smaller molecules avoiding the production of a heavier fraction. The higher the hydrogen pressure, the smaller was the yield of heavier fraction and the larger the yield of lighter fraction. Higher temperature accelerated the production of the heavier fraction. Donor solvents could reduce the production of the heavier fraction.     

Pressure and temperature effects on the hydrogenation of coal-derived asphaltene

Pressure and temperature effects on hydrogenation reactions were examined using coal-derived asphaltene at 390,420 and 450 °C, under 3 and 10 MPa of hydrogen partial pressure. Higher conversion was obtained at higher reaction temperatures. Benzene-insoluble material (Bl) was formed at higher temperatures especially at low hydrogen pressure, this Bl being one-third of the reaction product at 450 °C. From structural analysis of unreacted asphaltenes and product oils, at 390 °C, it was concluded that smaller molecular components convert to oil initially and the larger molecules remain as unreacted asphaltene. Under higher hydrogen pressure for all temperatures carbon aromaticity (f_a) and number of aromatic ring per structural unit (R_aus) in unreacted asphaltenes were lower than those under lower hydrogen pressure suggesting that hydrogenation of the aromatic nucleus was promoted by higher pressure. At lower hydrogen pressure, R_aus for asphaltenes at higher temperature is larger than that at lower temperature. This suggests that at lower hydrogen pressure, dehydrogenation or condensation reactions occur more easily. A large effect at higher hydrogen pressure was a reduction in the extent of condensation reactions. Higher reaction temperatures contribute to splitting of bridged linkages so reducing molecular size and degree of aromatization.     

Enzymatic synthesis of optically active ferrocenes by immobilized lipase from Candida Antarctica

Immobilized lipase (Candida Antarctica lipase, CAL) efficiently catalyzes the transesterification and amidation of the racemic ferrocenes, 1‐hydroxyethylferrocene, (±)‐ 1 , 1‐hydroxy[3](1,1′) ferrocenophane, (±)‐ 4 , 1‐amonoethylferrocene, (±)‐ 2 , and 1‐amono[3](1,1′) ferrocenophane, (±)‐ 5 , with acyl esters, resulting in the formation of R products possessing high enantiomeric purity. When 1‐hydroxyethylferrocene, (±)‐ 1 , and 1‐hydroxy[3](1,1′) ferrocenophane, (±)‐ 4 , was used as substrate diisopropyl ether was a suitable solvent. In the reaction conditions investigated, the use of vinyl acetate in diisopropyl ether gave the best yield of (R)‐ 1a (49%, 99% ee) after 2 h of incubation at 30 °C. But, with the amino ferrocenes, 1‐amonoethylferrocene, (±)‐ 2 , and 1‐amono[3](1,1′) ferrocenophane, (±)‐ 5 , as substrate, diisopropyl ether was unsuitable as a solvent owing to the low solubility of the substrate in this solvent. Using tetrahydrofuran as a solvent, enzymatic amidation of 1‐amonoethylferrocene, (±)‐ 2 , gave the best yield of (R)‐ 2a (21%, 99% ee) after 120 h of incubation at 30 °C. CAL working in organic solvent is able to efficiently carry out the resolution of ferrocenyl alcohol and amine derivatives which have similar structures, such as (±)‐ 1 and (±)‐ 2 , (±)‐ 4 and (±)‐ 5 which possess central chirality. This enzyme accepted only non‐bulky primary alcohols and amines as ferrocenyl substrates. © 1999 Society of Chemical Industry