Showing papers by "National Chemical Laboratory published in 1979"
TL;DR: In this paper, the asymmetric hydrogenation of methyl benzoylformate to R- (-) -methyl mandelate was studied using Pt-C catalysts modified with cinchonidine.
Abstract: The asymmetric hydrogenation of methyl benzoylformate to R- (-) -methyl mandelate was studied using Pt-C catalysts modified with cinchonidine. High asymmetric selectivities (over 80% optical yield) were attained in the hydrogenation using some ethers, esters, or benzene as solvent.
207 citations
TL;DR: Carbonsauren (II) werden with Cyanurchlorid (I) uber diskutierte Zwischenstufen in die Saurechloride (III) ubergefuhrt, die mit Alkoholen, Phenolen, Aminen oor auch Aminosauren direkt zu Estern, Amiden oder Peptiden (IV) umgesetzt werding as mentioned in this paper.
91 citations
TL;DR: An oxygen-deficient perovskite of composition SrFeO3−x selectively absorbs NO gas above approximately 100°C, and the analysis of the infrared spectrum of the system 14NO - 15NO - SIRF 3−x has revealed that the absorbed species in the system is possibly the nitrosyl ion (NO−) bound to the iron ion accomodating some oxygen vacancies as mentioned in this paper.
63 citations
TL;DR: In this article, the analysis of solid-solid reactions is discussed, including fundamental considerations, experimental techniques, analysis of pellet-pellet reactions, mixed powder reactions, role of the gas phase, and reactor design.
Abstract: This paper reviews some important aspects of the analysis of solid-solid reactions which include: fundamental considerations, experimental techniques, analysis of pellet-pellet reactions, analysis of mixed powder reactions, role of the gas phase, and reactor design. Illustrations are given wherever necessary. Examples of industrial applications, important systems studied, and the models used are tabulated.
58 citations
TL;DR: A high-temperature form of a brownmillerite-like compound Sr2Fe2O5, which has a perovskite structure with the oxygen vacancies randomly distributed, showed a remarkable NO decomposition at 700-900°C as mentioned in this paper.
54 citations
TL;DR: Palladium complex catalyzed carbonylation of organic halides in the presence of organotin compounds to give unsymmetrical ketones in moderate to excelent yields is disclosed.
53 citations
TL;DR: In this article, the unstable species aminoborane, BH2NH2, was identified as a reaction product of ammonia with diborane by microwave spectroscopy.
53 citations
51 citations
TL;DR: In this paper, the hydration of β-dicalcium silicate was followed at a fixed w/c ratio of 0.45 and at 10° to 40°C by analyzing the liquid phase in the paste, by determining free lime and combined water, and by electron microscopy.
Abstract: The hydration of β-dicalcium silicate was followed at a fixed w/c ratio of 0.45 and at 10° to 40°C by analyzing the liquid phase in the paste, by determining free lime and combined water, and by electron microscopy. The reaction proceeded from the induction period through a propagative surface nucleation-growth of the CSH stage and an Overall penetration reaction Sw; the kinetics of these stages are discussed.
34 citations
TL;DR: In this paper, the authors measured line widths for the Raman v 1, v 15 and infrared v 12 of C 6 ll 6 in C 6 D 6 solution, and compared with literature values.
34 citations
TL;DR: A mutant of Sclerotium rolfsii CPC 142 that secretes about two times more filter paper-degrading activity in NM-2 growth medium in submerged cultures than the parent strain was obtained by ultraviolet mutagenesis of crushed sclerotia, and the production of endo-beta-glucanase in the mutant was affected to a lesser extent.
Abstract: A mutant of Sclerotium rolfsii CPC 142 that secretes about two times more filter paper-degrading activity in NM-2 growth medium in submerged cultures than the parent strain was obtained by ultraviolet mutagenesis of crushed sclerotia. The production of endo-beta-glucanase in the mutant was affected to a lesser extent. With the parent strain, the addition of 3% rice bran to NM-2 medium was essential for optimal formation of cellulase, including filter paper-degrading activity. However, with the mutant the addition of rice bran to NM-2 medium increased the formation of endo-beta-glucanase but not filter paper-degrading or cellobiase activity. An altered control mechanism for the production of filter paper-degrading enzymes is suggested. The genome(s) controlling the cellulase complex of enzymes in the UV-8 mutant is not under coordinate control.
TL;DR: The carbon and energy source for aerobically grown cultures of Candida guilliermondii profoundly influenced the neutral lipid content and the fatty acid composition of the individual lipid components.
Abstract: The carbon and energy source for aerobically grown cultures ofCandida guilliermondii profoundly influenced the neutral lipid content and the fatty acid composition of the individual lipid components. Methanol (0.80%, w/v) grown cells cultivated at 30 C in presence of 0.025% ammonium sulfate contained 12% total lipids, 67% of which was neutral lipids. Glucose (0.74%, w/v) or ethanol (0.53%, w/v) grown cells contained 21–22% total lipids, 80% of which was neutral lipids, under the same conditions. Methanol-grown cells contained a decreased 18∶1 acid (52–54% of total fatty acids) and an increased 18∶2 acid (23–25%), as compared with glucose- or ethanol-grown cells which contained 57–66% 18∶1 acid and 8–14% 18∶2 acid, in both neutral and polar lipid fractions. The relationship between methanol metabolism and desaturation of fatty acid in yeast was discussed.
TL;DR: In this paper, it was found that dibenzophospholes cause considerable rate enhancement in comparison with diphenylphosphines as catalyst ligands, although they behave like phosphines of strong donor ability in terms of the product distribution.
TL;DR: In this article, a prototype piston engine using LaNi 5 H x as an energy conversion medium was developed, which consists of two metal hydride containers, each having about 700 g (1.6 moles) of LaNi5 H x powder, a cylinder and piston, and two electromagnetic valves which work and synchronize with the movement of the piston.
01 Apr 1979
TL;DR: In this paper, the Raman line shapes of six totally symetric bands of liquid cyclohexane have been measured as a function of pressure at 0.1-1.5 kbar and of temperature at 25-175°C.
Abstract: The Raman line shapes of six totally symetric bands of liquid cyclohexane have been measured as a function of pressure at 0.1–1.5 kbar and of temperature at 25–175°C. Densities and shear viscosities have also beeen measured, and the hard sphere diameter of the cyclohexane molecule has been evaluated from the analysis of the viscosity data. The observed isotropic line width for all modes studied increases with increasing pressure and increasing temperature. The essential features of the experimental data for ν 1 (2938 cm −1 ) and ν 2 (2852 cm −1 ) bands are interpreted in terms of the vibrational dephasing model. However, for the lower frequency ν 3 , ν 4 , ν 5 and ν 6 bands (1465 cm −1 to 388 cm −1 ), ħω ≈ kT and, therefore, only qualitative discussion of the experimental data is possible. The observed isotropic line widths δ obs , for the lower frequency bands show stronger temperature dependence than that found for δ obs of the ν 1 and ν 2 bands, and lower sensitivity to volume changes. Phenomenological discussion of the experimental data for the δ obs of the low frequency bands is presented.
TL;DR: In this paper, the thermal analysis of n-long chain alcohols CH3(CH3)n-1-OH, designated as Cn-OH (n = 16, 18, 20 and 22), and corresponding alkoxy ethanols CH 3(CH2)n1-OCH2CH2
TL;DR: In this paper, a process flow sheet of a sulfur-iodine cycle and its mass balance were made based on experimental results, and the heat balance for this cycle was made.
TL;DR: In this article, the Ramaman spectra of aqueous gallium chloride solutions are obtained in both liquid state at room temperature and glassy state at a given temperature and are discussed in terms of ionic equilibrium reactions.
TL;DR: The oleoresin from Hardwickia pinnata Roxb is shown to be a complex blend of sesquiterpenes and diterbenes as discussed by the authors, which consists of a series of closely related new diterpenoids of ent -clerodane type.
TL;DR: Two additional sesquiterpene lactones apart from parthenin have been shown to be allergenically active and Structures of these sesQuiterpenoids are presented.
Abstract: Parthenin has been reported as the active allergen in Parthenium hysterophorus contact sensitivity. A study was carried out to test various chemical fractions of the plant for isolating and identifying the exact allergens. Two additional sesquiterpene lactones apart from parthenin have been shown to be allergenically active. Structures of these sesquiterpenoids are presented. Photopatch tests do not indicate a photosensitizing capacity for these compounds.
TL;DR: In this paper, the rotational and centrifugal distortion constants have been determined for the normal and d2 species of trifluoroborane, and the molecular structure has been determined.
TL;DR: In this article, the heat capacity of UP 1− x S x (x = 0.0, 0.4 S 0.6, 0., 0.8, 1.0) has been measured from 80 to 670 K by laser-flash calorimetry and all samples exhibit an anomaly corresponding to the magnetic transition.
TL;DR: In this article, the Coriolis interaction and CNDO/2 calculation of cyclopropane-h 6 and -d 6 absorption intensities were analyzed in order to determine the intensity parameter (∂ p /∂ S j ) with the help of information from information from the COROLIANS interaction.
TL;DR: In this article, the structure determination of four new diterpene acids from the oleoresin of Hardwickia pinnata Roxb is described, and the four acids belong to ent-clerodane type and have been chemically correlated with (−)-hardwickiic acid of proven absolute stereochemistry.
TL;DR: The regeneration of cell wall and continued cell division with formation of viable callus from rose protoplasts are described.
TL;DR: In this article, a high-sensitivity apparatus for thermoanalytical microscopy under reflected light has been designed and has been applied to studies of (1) the mechanism of the polymorphic transition of stearic acid, (2) the fine structure of the smectic, cholesteric, and cholesteryl nonanoate and (3) the process of the multiplication of yeast bacteria.
TL;DR: In this article, an attempt has been made to give a more realistic molecular potential for carbon tetrafluoride by using published X-ray diffraction data for α-CF4.
Abstract: An attempt has been made to give a more realistic molecular potential for carbon tetrafluoride by using published X-ray diffraction data for α-CF4. It was found that an addition of anisotropic Lennard-Jones potentials between nonbonded atoms is preferable for molecular interactions in crystal. The values of the potential parameters are evaluated and give a reasonable interpretation of the temperature dependence of the lattice parameters.
TL;DR: In this article, the concept of ring strain in five-membered rings (about 5 × 2 kcal/mol in the background of thermochemical data) has been reviewed and amended by providing a special set of energy terms for the (C, O, N, S) -ring skeleton which is considered strain-free if the hydrogen atom is th...
Abstract: The bond energy scheme is extended to nitrogen compounds by correlating experimental thermochemical data reviewed to 1980. Heats of formation and atomization energy terms are provided for bonds of nitrogen with other elements: H, C, O, N, S, and halogens. An overall precision of 3 kcal/mol was attainable at the best, which is rather low for chemical reaction kinetics purpose. This is attributable mainly to the intrinsically unpredictable bond energies of the nitrogen atom due to the “lone-pair” electrons participation in the valence bonding, rendering nitrogen bonds specific and less transferable. The nearest-neighbor interactions on nitrogen atom are also severe but predictable if sufficient energy terms are generated. The concept of ring strain in five-membered rings (about 5 × 2 kcal/mol in the background of thermochemical data) has been reviewed and amended by providing a special set of energy terms for the (C, O, N, S) -ring skeleton which is considered strain-free if the hydrogen atom is th...