A method is described for the determination of trace amounts of phosphorus present in terephthaloyl chloride (TCL). Phosphorus was extracted from the sample by distilled water. It was converted into molybdophosphoric acid, extracted with n-butyl acetate and molybdenum in the organic extract determined by catalytic polarography. Charging current compensation was employed to improve precision and detecton limit. The method enabled the determination of 0.0005 % P in TCL and the relative standard deviation was 4.2%.
Post-buckling analysis of a uniform cantilever column under a tip concentrated subtangential follower force has been studied. The solution of the problem is obtained in terms of elliptic integrals. The load deflection curves are presented.
This review highlights the different methods of synthesizing metal containing polymeric systems and an evaluation of their physico-chemical properties. The essential bulk properties of the polymer systems such as thermal stability, electrical and conductivity characteristics are significantly affected by incorporation of metal ions, due mainly to structural changes in the polymer network and varying extents of charge transfer and related interactions occurring in the metal modified macromolecular network. The potential applications of these metal containing polymers are briefly described.
This paper presents the extraction of nickel using nitric acid from waste nickel catalyst used in hydrogenation of oils and fats. The compounds of sulphur, phosphorus, nitrogen, etc., poisoning agents of catalyst and other acid insoluble fractions, are removed in order to utilize the waste catalyst. The extraction process has been optimized. It has been observed that countercurrent extraction up to three-stage with three normal acid and one hour duration are the best process conditions.
Large scale generation of plastic waste has generated considerable interest in seeking innovative solutions to waste recycling and reuse. The major driving force are both greater public awareness of the environment and government legislation. This paper briefly reviews the current state of the art in recycling technology. These comprise of primary, secondary and tertiary recycling processes. The various processes are described with reference to the nature of waste, manner of processing and conversion to products. Attempts to produce- monomers and value added derivatives from tertiary recycling are highlighted. Pyrolytic processes which produce fuel oils are discussed. Emerging technological trends indicate that recycle products will be increasingly sold on the basis of their property profile instead of generic brand names. Furthermore, plastic technologies such as blending, reactive processing, surface activation, compatibilization and impact modification will be increasingly used, making recycling both practical and profitable.
Ionomers are a specific class of ion containing polymers which typically possess less than 10 mole % ionic groups covalently attached to a hydrocarbon backbone. This review summarizes recent developments in the ionomer field including synthesis, structure, physical properties, solution behaviour, ionomer blends based on specific interactions and commercial applications. Ionomers are prepared either by copolymerization of an appropriate vinyl monomer or by functionalization of a hydrocarbon polymer chain- Copolymers of ethylene and methacrylic acid, suitably neutralized, are those ionomers of greatest commercial success. However, sulphonation chemistry applied to polystyrene or ethylene propylene diene monomer (EPDM), has led to new ionomer families which have been the subject of intensive research. Other classes of ionomers are described in this review. Most ionomers in the forms of neu salts display evidence of ion pair association which is responsible for their unique properties. Structural studies have shown that ion pair aggregates exist which can give rise to physical crosslinks, which under some circumstances can approach the performance of covalent crosslinks. Thus, ionically crosslinked elastomers can behave as thermoplastic elastomers wherein the crosslinks are reversibly dissociated with changes in temperature. These ionic crosslinks are also manifested in hydrocarbon solutions where they give rise to enhanced viscosity at polymer concentrations > c*, the coil overlap concentration. This review describes the solution behaviour of sulphonate ionomers in detail in solvents of different polarity. A number of commercial applications of selected ionomers are reviewed, including their use as thermoplastic elastomers, pressure sensitive adhesives, and drilling fluid viscosifiers.
The performance of coconut(I) and hydrogenated soyabean(II) oils as stationary phases for Gas Liquid Chromatography (GLC) has been evaluated. Several organic compounds, viz., aliphatic, aromatic and chlorinated hydrocarbons, cyclic ethers, alcohols, ketones and esters are used as test solutes. Classification of these stationary phases is carried out by different approaches, viz., McReynold's method. Novak's thermodynamic approach and Snyder's selectivity triangle. The results indicate that these stationary phases fall in the medium polar range. Close boiling compounds of industrial importance are satisfactorily resolved on these stationary phases. Stability studies revealed that I and II are quite stable up to 200 and 250-degrees-C respectively. It is concluded that I and II can be used as effective, versatile, easily available and cheap stationary phases for GLC.
The use of sodium cotton sulphonate as corrosion inhibitor for aluminum in 2 M HCl solution was studied by hydrogen evolution and thermometric methods. The two methods gave concordant results. The results indicate that the additive reduces the corrosion rate by way of adsorption through the pi electrons in the double bonds. The adsorption of the additive was found to obey Langmuir's adsorption isotherm.
A model of two species of microorganisms competing in a spatially heterogeneous batch fermenter is analysed. Using stability conditions without computation, practically useful inferences are derived about the effects of important parameters such as the maximum specific growth rates and the inoculum sizes. A threshold condition is derived for Turing instability, and it is argued that a parametrically sensitive population is more likely to 'jump' from a stable state to an unstable one, leading to spontaneous pattern formation.
Some aspects of industrial relevance for the manufacture of di-octyl-phthalate (DOP), using methane sulphonic acid (MSA) as the catalyst have been studied on the bench scale level. The kinetic parameters like rate constant, order with respect to the reactants and catalyst, activation energy, frequency factor have been determined. The MSA catalyst was found to be better catalyst than the conventionally used p-TSA (para-toluene sulphonic acid) to produce DOP.
Experimental studies on air-water flow through orfices mounted on horizontal pipe have been presented. The method of dimensional analysis has been used to correlate the experimental data. The correlation developed predicts the two-phase frictional pressure drop with acceptable statistical accuracy.
Di(2-ethylhexyl)phosphoric acid (D2EHPA) is used extensively in the solvent extraction of various metals from aqueous solutions. Various methods of preparation of D2EHPA are reviewed. The laboratory scale process development work carried out for preparation of D2EHPA from phosphorous oxychloride and 2-ethylhexanol is described. The effects of various process parameters like (i) mole ratio of POCl3 to 2-ethythexanol (2EHA), (ii) order of addition of these two reagents, (iii) temperature of the reaction and (iv) use of inert solvent on the yield and composition of crude D2EHPA are studied. The scheme of refining of crude D2EHPA is based on (i) solubility of sodium salt of M2EHPA in 0.5 M Na2CO3 solution, (ii) solubility of neutrals in an organic solvent and (iii) formation of stable microemulsion between sodium salt of D2EPHA, water and an organic solvent. The performance of prepared sample of D2EHPA and Mobil USA product in the extraction of uranium, neodymium and praseodymium from their acidic chloride solutions are comparable.
Benzophenone undergoes a one-step, two-electron, irreversible reduction at the mercury and glassy carbon electrodes. The halobenzophenones exhibit two reduction waves. The more positive wave is due to the reductive cleavage of the C - X(X = Cl, Br) bond involving two electrons. This is unlike the behaviour observed in aqueous media. Molten acetamide behaves like water for most electrochemical reduction but like an aprotic solvent in the presence of 0.1 M NaOH for some reduction processes.
Comparative assessment of the oxidation behaviour of three zirconium alloys has been done on the basis of kinetics of oxidation in steam at temperatures between 400 and 1200-degrees-C. Structural analysis of oxide films indicated that the films were predominantly monoclinic. Relative amounts of stresses in the films as estimated from peak shifts in XRD patterns showed that the films were stress free at 1200-degrees-C while at lower temperatures the stress was of the order 5 x 10(5) psi. Micrographic examination of the cross-sections of oxidized samples was carried out using colour micrography and showed a difference in the morphology of the alpha layer in Zircaloy on one hand and Nb-containing alloys on the other. The elemental redistribution due to oxidation was markedly seen at 1200-degrees-C. The difference in oxidation behaviour of the alloys has been explained.
Viscosities of three mixtures of m-xylene with acetic acid, propionic acid and butanol have been determined at 293.15, 303.15, 313.15, and 323.15 K, over the complete compositional range. Using the viscosity-composition-temperature data excess viscosity and the energies of activation of flow have been determined, and their variation with composition have been discussed. The predictive ability of some of the existing correlations for mixture viscosities have been compared.
The electrodeposition of nickel-iron alloys from alkaline sulphate bath containing diammonium hydrogen citrate and amino acids has been studied. The deposition potential, the percentage composition of the alloy and the current efficiency of the bath solutions are determined as a function of bath composition, pH, current density, temperature, agitation of the bath solution and the concentration of addition agents. The electroplated alloys exhibited fee structure. Throwing power is evaluated. Functional properties such as adhesion, hardness, porosity, magnetic properties and corrosion resistance of the alloys, electroplated under optimum plating conditions are evaluated. The anomalous codeposition of Fe is minimised and the quality of the plated alloys improved, only with the combination of diammonium hydrogen citrate and amino acid.
The excess volumes of binary mixtures of o-xylene and m-xylene with 2-propanol, 2-methyl-1-propanol and 3-methyl-1-butanol have been measured at 303.15 K. V-E is positive over the whole range of composition in all the mixtures. The results are compared with those for mixtures of toluene with the corresponding iso-alcohols.
Cyclic voltammetric studies on nickel in alkali sulphur solutions revealed the formation of divalent hydroxide and sulphide of nickel. Sulphides undergo oxidation to sulphur and sulphate on nickel surface. The formation of nickel sulphide and soluble nickel sulphur complexes were envisaged. The formation of higher valent oxides of nickel was inhibited by the presence of sulphur. The oxygen evolution reaction was favoured on sulphate covered surface.
This review summarizes the recent developments in the synthesis of new speciality macromolecules by the use of living carbocationic polymerization processes. After discussing the fundamentals of carbocationic macromolecular engineering and living polymerizations, a wide variety of useful materials such as macromonomers, telechelics, polymers with pendant functional groups, star-shaped macromolecules, block and graft copolymers, and networks available by the use of living carbocationic polymerization processes are described.
