Showing papers by "National Chemical Laboratory published in 1976"
TL;DR: In this paper, two steps of the overall mechanism have been identified, namely, dissociation of CO and hydrogenation of deposited carbon by adsorbed hydrogen, and they have been studied on Ni and Ni-Cu alloy films at low pressures, at temperatures of 250-350 °C.
465 citations
TL;DR: In this paper, the i.r. absorption intensities of methane and its deutero-and fluoro-derivatives; CH 4, CD 4, CH 3 D, CHD 3, CH 2 D 2, CF 4, CH 3 F, CHF 3, and CDF 3 have been measured under high pressure.
99 citations
TL;DR: In this article, a hybrid thermochemical-electrolysis water splitting cycle is proposed and preliminary experimental results are presented, where the electrolytic step consists of the cathodic reduction of hydrochloric acid and the anodic oxidation of Cu + to Cu 2+.
50 citations
TL;DR: In this article, a new method of chemical deposition consisting of the formation of thin films of a substance at the interface of a solution and a gas was used to form thin film of semiconducting and photoconducting CdS. The structural, electrical and optical properties of these films were studied.
41 citations
TL;DR: In this article, a generalised zone reaction model for gas-solid reactions is proposed, which reduces to the existing models under certain specific specific conditions which are defined in terms of the width of the reaction zone.
38 citations
TL;DR: X-ray photoelectron spectroscopy has been used to determine the oxidation state of copper in various kinds of copper minerals, such as carrollite Co2CuS4, germanite Cu3(Ge, Fe) (S, As)4 and covelline CuS as mentioned in this paper.
Abstract: X-ray photoelectron spectroscopy has been used to determine the oxidation state of copper in various kinds of copper minerals. Cuprite Cu2O is found to be stable to air oxidation. Photoelectron spectra of carrollite Co2CuS4, germanite Cu3(Ge, Fe) (S, As)4 and covelline CuS reveal that these minerals contain univalent copper.
38 citations
TL;DR: In this paper, the dipole moment derivatives with respect to a bond length or a valence angle have been determined for gaseous CH and CD 2 F 2, and the determined values of a CH and a CF are −0.73 ± 0.14 and −4.23 ± 0.84 D/A, respectively.
27 citations
TL;DR: Results are presented to show that parthenin, a sesquiterpene lactone, is the major antigen which produces contact dermatitis in sensitive human beings.
Abstract: The increasing incidence of contact dermatitis due to the wild growth of the weed Parthenium hysterophorus Linn, in many parts of India has prompted chemical analysis coupled with clinical testing to isolate the offending agent Results are presented to show that parthenin, a sesquiterpene lactone, is the major antigen which produces contact dermatitis in sensitive human beings
26 citations
25 citations
TL;DR: In this article, a copolymerization of acrylic acid and N-vinylpyrrolidone (NVP) was performed in aqueous solution at 30°C in the pH range 4-9 and the monomer reactivity ratios (r1 for AA and r2 for NVP) were determined as a function of pH from the high conversion data.
Abstract: Acrylic acid (AA) and N-vinylpyrrolidone (NVP) were copolymerized in aqueous solution at 30°C in the pH range 4–9 and the monomer reactivity ratios (r1 for AA and r2 for NVP) were determined as a function of pH from the high conversion data by using both the differential (YBR) and the integrated copolymerization equations. The value of r1 decreased from 5.2 at pH 4 to a minimum of 1.3 at pH 5 and then increased to 8.1, 6.6, and 7.2 at pH 7, 8, and 9, respectively. Addition of 1M NaCl at pH 6.5 restored the r1 nearly to that at pH 4, the predominantly un-ionized acid. The r2 values for NVP were nearly zero at all pH values except at pH 5. The variation of the reactivity ratios with pH was examined in terms of the electrostatic interactions between the ionized monomer molecules, the rate of homopolymerization of acrylic acid, and the cation binding to the poly(acrylic acid) molecules. The r2 values for NVP compared favorably with the literature values reported in bulk and organic solvent systems, although r1 values are much higher.
20 citations
TL;DR: In this paper, the authors consider the case of a porous catalyst and show that the resulting rate of reaction is governed by both the kinetics of the reaction and the transport process (or processes) which gives rise to the gradient.
Abstract: Reactions occurring on the surface of a porous catalyst are accompanied by transport of heat and mass in the pores of the catalyst and across the boundary layer at the external surface. Under the conditions normally encountered in catalytic reactors, heat and mass fluxes can be large enough to cause finite gradients of concentration and temperature in the solid as well as in the film. In such instances the resulting rate of reaction is governed by both the kinetics of the reaction and the transport process (or processes) which gives rise to the gradient. Hence the dependence of the overall or global rate on temperature and the partial pressures of the reacting species can no more be expressed by the intrinsic kinetics of the reaction but is influenced also by the transport parameters of the system. In other words, in the presence of finite transport limitations the catalyst exhibits kinetics falsified by transport processes. This has been referred to as “disguised kinetics” by Wei [l]. Carberry [...
TL;DR: In this paper, photo-irradiation of longibornyl iodide in n-heptane containing some triethylamine as scavenger for hydrogen iodide, furnished rearranged hydrocarbons (longifolene, longicyclene and longibORN-8-ene).
TL;DR: In this article, factors influencing the asymmetric selectivity in the hydrogenation of methyl acetoacetate to methyl 3-hydroxybutyrate by the nickel-palladium-kieselguhr catalyst were studied in order to improve the optical purity of the product.
Abstract: Factors influencing the asymmetric selectivity in the hydrogenation of methyl acetoacetate to methyl 3-hydroxybutyrate by the nickel-palladium-kieselguhr catalyst were studied in order to improve the optical purity of the product. Optimum pH-value of the tartaric acid solution for modification of the catalyst was found to be 4.34.5. A slight increase of the asymmetric yield was attained by preheating the catalysts in the solvent and/or by preheating the reaction mixtures under hydrogen pressure without stirring. Thus, the product having [α] 20D-20.10° (optical purity 91.2%) was obtained in the best condition.
TL;DR: In this paper, the performance of a cocurrent up-flow this paper with glass beads was studied using the oxidation reaction of sodium sulfite, at a reaction temperature of 20°C.
Abstract: Packed-bed cocurrent up-flow reactors gave better results than conventional trickling flow reactors in hydrodesulfurization of heavy oil. To find the characteristics of this up-flow type reactor, liquid-phase mass transfer coefficient, gas-liquid interfacial area and gas holdup in a column packed with 0.1, 0.28 or 0.43 cm glass beads were studied using the oxidation reaction of sodium sulfite. Experiments were carried out at a reaction temperature of 20°C. Superficial liquid and gas velocities based on empty column, ul and ug, were 1-6 and 0.5-6cm/sec, respectively, for any size of glass beads. With the values of ul and ug, glass beads bed remained stationary, expanded or fluidized. Stagnant gas holdup was observed under the condition of ul
TL;DR: Citrate lyase from Streptococcus facealis has been purified to homogeneity and shows only a weak reaction inactivation and the enzyme complex is not associated with acetylating enzyme activity for reactivation of the HS-citrate Lyase in presence of acetate and ATP.
TL;DR: In this article, zinc sulfide phosphors activated by copper, silver or manganese were ground in a dry or wet state, and the changes of their luminescent properties as well as crystal structure have been measured.
TL;DR: In this paper, the authors describe work now underway at the National Chemical Laboratory for Industry (N.C.L.I.) in Tokyo, Japan on the production of hydrogen from H2S or H2O by thermochemical processes.
TL;DR: In this paper, the fundamental frequencies of 1,2-dibromoethane CH 2 Br and CD 2 BrCD 2 Br were determined by comparison with those of related molecules.
TL;DR: In this paper, the applicability of X-ray photoelectron spectroscopy to the determination of the oxidation state of vanadium in minerals is studied, and vanadium-rich aegirine (Na, Ca) (Fe, V)Si2O6 is found to contain vanadium as trivalent state.
Abstract: The applicability of X-ray photoelectron spectroscopy to the determination of the oxidation state of vanadium in minerals is studied. Using this technique, vanadium-rich aegirine (Na, Ca) (Fe, V)Si2O6 is found to contain vanadium as trivalent state.
TL;DR: In this paper, approximate equations of currentpotential curves are given for electrode processes with a coupled homogeneous chemical reaction, and the equations hold in the whole range of the arguments, particularly including the upper and lower extremities.
TL;DR: In this paper, the π,π * absorption spectra of fluorenone and 9,10-phenanthrenequinone were examined and it was found that there is an exact similarity between these two spectra up to near 250 nm.
TL;DR: In this article, the heat and mass balance equations for diffusion accompanied by chemical reaction in a catalyst pellet are solved for reactions following a common class of Langmuir-Hinshelwood kinetics and general-order kinetics.
TL;DR: In this article, the size and number of fine sodium chloride crystals on the inside wall of a column were investigated with a scanning electron microscope, and it was shown that the thermal stability of such a column is superior to that of a wall-coated open-tubular column.
TL;DR: The isolation and stereochemistry of 3-hydroxylongifolaldehyde (4), the missing key-compound in the earlier proposed mechanism for the abnormal perbenzoic acid oxidation of longifolene is described in this paper.
TL;DR: In this paper, the half band widths of dichloromethane CH 2 Cl 2 were measured in the liquid state and in solutions, and it was concluded that the reorientational motion of the dichlormethane molecule in liquid state can not explain the whole part of the band broadening of the i.r. absorption spectra.
TL;DR: Polyimides were prepared by reacting 3,3′-sulfonyl-bis(phenyl isocyanate) [SDI] with pyromellitic dianhydride [PMDA] and also with 3, 3′, 4, 4′-benzophenone tetracarboxylic acid dianohydride [BPTD].
Abstract: Polyimides were prepared by reacting 3,3′-sulfonyl-bis(phenyl isocyanate) [SDI] with pyromellitic dianhydride [PMDA] and also with 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride [BPTD]. Their properties were compared with those obtained by reacting 4,4′-methylene-bis(phenyl isocyanate) [MDI] with respective dianhydrides.
Polyimide wurden durch die Reaktion von 3,3′-Sulfonyl-bis(phenylisocyanat) [SDI] mit Pyromellitsauredianhydriden [PMDA] und 3,3′,4,4′-Benzophenon-tetracarbonsauredianhydriden (BPTD) hergestellt. Ihre Eigenschaften wurden mit denjenigen der durch die Reaktion zwischen 4,4′-Methylen-bis(phenylisocyanat) [MDI] und den entsprechenden Diahydriden gewonnenen Polyimiden verglichen.