Showing papers by "National Chemical Laboratory published in 1970"
TL;DR: In this article, it is suggested that the primary lac acid is jalaric acid and that shellolic and laksholic acids (and their epimers) arise from shellolic acid by a Cannizzaro reaction under conditions of alkaline hydrolysis.
40 citations
TL;DR: An electron diffraction study has been made on vacuum-deposited films of Ag2Se and Ag2Te on different substrates at various temperatures and the transition of α to β phase occurred reversibly at about 136 °C as mentioned in this paper.
28 citations
TL;DR: In this paper, a modified procedure for the isolation of hard resin from seed-lac is described, and an integrated procedure for isolation of various lac acids from the "hard resin" hydrolysate has been developed.
24 citations
TL;DR: Isolongifolene epoxide undergoes novel rearrangements on treatment with 1% HCl in CHCl3 or on being exposed to active adsorbent (Al2O3, SiO2-gel).
17 citations
TL;DR: Starting with camphene-1-carboxylic acid (III), both C13-keto acid (II) and (±)-isolongifolene itself, have been synthesized by an unambiguous route.
17 citations
15 citations
TL;DR: In this paper, the results of adiabatic compressibility measurements of poly(acrylic acid) and polyacrylamide along with their corresponding monomers and two poly(sodium acrylates) obtained by neutralizing the polyacid 25% and 100% with sodium hydroxide have been described.
Abstract: The results of adiabatic compressibility measurements of poly(acrylic acid) and polyacrylamide along with their corresponding monomers and two poly(sodium acrylates) obtained by neutralizing the polyacid 25% and 100% with sodium hydroxide have been described. The total adiabatic compressibility of poly(acrylic acid) solution is higher than that of the corresponding salt solutions or of polyacrylamide solutions. The unneutralized acid does not dissociate much, even in dilute solution, and the magnitude of electrostriction in polyamide is greater than in acid. The ΦV2 and ΦK2 values for monomers and polymers are seen to be almost concentration independent, and so are the sodium salts of the polyacid. Poly(acrylic acid) and poly(acrylamide) are structurally closely related polymers, and water must be bound to them through polar groups either by hydrogen bonding or by dipole attraction. The hydrophobic part of the solute, because of compact orientation of water and solute in the boundary region, causes a decrease in solvent volume and therefore in the values of ΦV2 and ΦK2. On the other hand, intermolecular hydrogen bonding between the polar groups increases the volume and counterbalances the hydrophobic effect. Because of these two counteracting effects, the observed ΦV2 and ΦK2 values are seen to be concentration independent. Contrary to the observation with poly(methacrylic acid)1 and its sodium salts, the solvated counter-ions in case of poly(sodium acrylates) make no special contribution in the dilute region. In 100% neutralized polyacid, the dissociation of counterions is complete, and the magnitude of electrostriction is highest in this case. Accordingly, lowest ΦV2 and ΦK2 values (37.0 cc/mole and −50.50 × 10−3 cc bar−1 mole−1) are observed. However, the dissociation and therefore the magnitude of electrostriction are somewhat reduced in the presence of 1.0M NaCl solution; and, accordingly, the values increase to 42.80 cc/mole and −33.0 × 10−4 cc bar−1, mole−1, respectively. The limiting values for the apparent molal volume and the apparent molal compressibility for the polymers show a considerable decrease over those of the monomers. The values of ΦV20 and ΦK20 per methyl group are less in the polymers than in the monomers, and this has been attributed to water clusters that become stronger and better formed as the molecules grow larger and larger. The molar volumes of acrylic acid and methacrylic acid are decreased, while those of acrylamide and methacrylamide are increased when dissolved in water to form an infinitely dilute solution.
14 citations
TL;DR: A study of ascorbic acid osazones by spectrosocopic methods shows that they are γ- lactones, not δ-lactones as claimed recently, and it is found that they mutarotate in solution.
12 citations
TL;DR: In this paper, the structure of the secondary alcohol, which is the major alcohol, has been elucidated and characterized as longibornan-9-ol, arising by transannular hydration of longifolene.
11 citations
TL;DR: In this article, an acid-catalysed disproportionation of 7-methoxy-1,3,4-trimethyl-1 2,2, 3,4, 4,6,7,8,9,10,10hexahydrophenanthridine (XII) gave a mixture of the corresponding cis- and trans-derivatives in similar proportions.
11 citations
TL;DR: Pure lac resin has been oxidized and then hydrolysed to furnish a mixture of products, which were carefully separated and identified and enabled the authors to determine the points of attachment of constituent lac adds in the pure lac resin.
TL;DR: In this article, the fragmentation modes of some epimeric 7-substituted norbornenes have been established from deuteration and high resolution studies, and it has been shown that stereochemical differences have very little influence in directing the fragmentation mode of these epimers.
Abstract: The fragmentation modes of some epimeric 7-substituted norbornenes have been established from deuteration and high resolution studies. Stereochemical differences were found to have very little influence in directing the fragmentation modes of these epimers. Formation of common intermediates or transition states by ring opening process has been proposed to rationalise the mass spectral behaviour of these compounds.
01 May 1970
TL;DR: The investigations embodied in the paper describe different methods of culturing tissues of Tectona grandis (teak), Artocarpus heterophyllus (jack),orus alba (mulberry) and Populus nigra (poplar) and, of these, teak, jack and mulberry tissues have been established in culture for the first time.
Abstract: The investigations embodied in the paper describe different methods of culturing tissues ofTectona grandis (teak),Artocarpus heterophyllus (jack),Morus alba (mulberry) andPopulus nigra (poplar). Of these, teak, jack and mulberry tissues have been established in culture for the first time. Teak, mulberry and poplar tissues grow well on Murashige and Skoog’s medium containing 1·0 ppm glycine, while jack tissue grows well on Blaydes’ medium. The tissues of teak, grown on Marashige and Skoog’s medium containing 3·2 mg. glycine and gibberellic acid, have good pigmentation. Jack tissue requires a specific higher temperature (30° C.) for its growth.
TL;DR: The particulate acetylcholinesterase of ox brain caudate nucleus was obtained in stable, soluble form by digestion with pancreatic elastase and was rapidly and irreversibly inactivated when a solution containing enzyme, phosphate, and thioethanol was frozen.
TL;DR: Isolongifolene has been systematically degraded to a bisnor-keto acid, the spectral characteristics of which are in full accord with the structure (II) assigned earlier.
TL;DR: In this article, a new general bond energy scheme is developed with low standard error of ± 0.28 kcal/mole which is close to the experimental uncertainty, and the energy terms of the new scheme are transferable to other non-hydrocarbon organic compounds for which a general scheme is under way.
Abstract: Results of application of seven well-known bond energy/group contribution methods to the experimental data on heats of formation of 70 alkanes, including a few polymers, are reported. The earlier claims of accuracy of many of these schemes become untenable with the emergence of new data on nonanes and polymers, calling for more parameters to cope with the steric interaction energy in higher branched alkanes. A new general bond energy scheme is developed with low standard error of ±0.28 kcal/mole which is close to the experimental uncertainty. Heats of formation of some polyolefin structures are predicted for the experimental verification in the future. The energy terms of the new scheme are transferable to other non-hydrocarbon organic compounds for which a general scheme is under way.
TL;DR: Two possible mechanisms of degradation of isobutyrate have been suggested and a plausible pathway has been outlined for the terminal oxidation pattern in the Pseudomonad (PL-strain).
Abstract: The organism grown on Δ1-p-menthene was found to grow without any lag on methyl isopropyl ketone, isobutyrate, succinate, malate, lactate and acetate. Isobutyrate or acetate grown cells grew on Δ1-p-menthene after a lag and showed comparatively little growth on β-isopropyl pimelic acid.
TL;DR: Dehydrogenation of isolongifolene over 10% PdC, in the vapour phase, at 450-± 5° gave in ∼23% yield a mixture of naphthalenes, consisting essentially of 1-methylnaphthalene (7·5%), 1methyl-7-isopropylnaphalene (eudalene, 67·5), 1-mixture of 1,methyl-6-isophropyl naphalenes (2·8%), and 1,6-dimethyl-
TL;DR: In this article, the VCl4-AlEt3 catalyst system was used to polymerize methyl methacrylate at 40°C with the VCL4-Et 3 catalyst system in n-hexane.
Abstract: Methyl methacrylate was polymerized at 40°C with the VCl4–AlEt3 catalyst system in n-hexane. The rate of polymerization was proportional to the catalyst and monomer concentration at Al/V ratio of 2, indicating a coordinate anionic mechanism of polymerization. NMR spectra were further used to confirm the mechanism of polymerization and stability of active sites responsible for isotacticity.
TL;DR: Physical properties of monomolecular films such as pressure area isotherms, rates of spreading, and equilibrium spreading pressures have been studied at 25°C for n-alkoxy propanols and butanols having the general formula CnOC3H6OH and Cn ǫ O4H3OH, where n = 16, 18, 20, and 22 as discussed by the authors.
TL;DR: The ideal gas state entropies at 298.15°K are: maleic anhydride, 71.9; β-propiolactone, 69.1; cyclopentadiene, 65.3; diketene, 72.7; and carbon suboxide, 66.0 cal/degmole as discussed by the authors.
Abstract: Thermodynamic functions of ten monomeric compounds have been calculated for three temperatures by the statistical method using molecular structural data and vibrational assignments. The ideal gas state entropies at 298.15°K are: maleic anhydride, 71.9; β-propiolactone, 69.1; vinylene carbonate, 70.1; cyclopentadiene, 65.3; diketene, 72.3; cyclopropene, 58.7, vinyl fluoride, 60.4; ethyleneimine, 62.8; butatriene, 71.7; and carbon suboxide, 66.0 cal./deg-mole. The standard free energies and equilibrium constants of formation are also derived by using mostly the published data on the heats of formation of these monomers.
TL;DR: In this paper, the primary cyclic monomer (methyl cycloeleostearate-I) has been obtained and unambiguously shown to be methyl 5-butyl-1,3-cyclohexadiene-6-caprylate (IV).
TL;DR: In this paper, the chlorination products from 3-pentadecenyl phenol, phenol acetate and methyl ether have been prepared and tested as plasticizer extenders for PCV.
TL;DR: In this article, the oxidation of benzone has been studied in an adiabatic semifluidized mixed tubular (MT) reactor, and a definite improvement is possible when the oxidation is carried out in this reactor, as observed by a comparison of the experimental results obtained in tubular, mixed, and MT reactors under different conditions.
Abstract: Combined reactors in which the mixed reactor is followed by a tubular reactor can be optimal for a large number of simple adiabatic exothermal reactions. In the present paper, optimality criteria defined earlier for simple reactions involving a single reactant species have been extended to reactions involving two reactant species and for a system of consecutive reactions.
The oxidation of benzone has been studied in an adiabatic semifluidized mixed tubular (MT) reactor. A definite improvement is possible when the oxidation is carried out in this reactor, as observed by a comparison of the experimental results obtained in tubular, mixed, and MT reactors under adiabatic conditions.
TL;DR: In this paper, one carrier space-charge-limited current is studied in CrCdS-Cr diodes or sandwiches prepared by vapour deposition technique.
Abstract: One carrier space-charge-limited current is studied in CrCdSCr diodes or sandwiches prepared by vapour deposition technique. The ohmic contacts with CdS are made of evaporated chromium. The current voltage characteristics are measured by the slowly varying triangular pulses. The thickness of the CdS films are in the range of 0·2–0·5 μ as estimated by the weight difference method. It has been observed that at low voltages, the ohmic region is dominant whereas at higher voltages a V 3 2 /d 5 2 dependence of current is found. A theoretical relationship between the voltage and the current density is obtained assuming E −1 2 dependence of mobility which is in agreement with the experimental results.
TL;DR: In this paper, a cyclokamlolenate-based intramolecular thermal cyclization of conjugated trienes, discovered with methyl eleostearate, has been extended to its ω-hydroxy analogue, viz. methyl kamlolenates.
01 Jan 1970