bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclic voltammetric behaviour and some surface characteristics of the lead electrode in aqueous HCL solutions
Authors: El‐Halim A. M. Abd , Fawzy M. H. , Saty A.
Published: July 2010

The positive linear sweep voltammograms of lead were investigated in 0.01–2.00 M aqueous HCl solutions. The results revealed the occurrence of one anodic current peak as the result of formation of a thin PbCl2 surface layer. Intensive study of the electrochemical behaviour of the lead electrode in 1.00 M HCl solution was carried out by cyclic voltammetry. The results indicated that the formation of PbCl2 is a reversible process controlled by diffusion of Cl− ions to the electrode surface. Controlling the voltammetric conditions enabled the building up of a relatively thick and porous PbCl2 layer that could resist rupture or breakdown. In addition, the electrode surface products were examined by scanning electron microscopy and X‐ray diffractometry. The morphology of the as‐formed PbCl2 layers showed a primitive dependence on the voltammetric conditions. X‐ray diffraction analysis proved that only PbCl2 was formed on the electrode surface and no other products could be detected.
Propranolol hydrochloride release behaviour of crosslinked chitosan membranes
Authors: Thacharodi D. , Rao K. Panduranga
Published: July 2010

Chitosan membranes of 20 μm thickness were prepared by a solvent evaporation technique and crosslinked with different concentrations of glutaraldehyde to obtain membranes of various degrees of crosslinking. These membranes were characterized by thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) and tensile strength studies. The effect of crosslinking on the permeability of membranes to propranolol hydrochloride was evaluated by permeation studies conducted in static glass diffusion cells. A decrease in the thermal stability of chitosan membranes due to crosslinking was observed. The tensile strength of the membranes was improved by crosslinking. The introduction of crosslink points within the membrane reduced its permeability to propranolol hydrochloride as evidenced by decreased permeability and diffusion coefficients. Permeability studies revealed the operation of a pore mechanism in the transport of hydrophilic agents such as propranolol hydrochloride through chitosan and crosslinked chitosan membranes.
Catalytic splitting of acetals to unsaturated ethers
Authors: Červeny Libor , Winklerová Petra , Marhoul Antonín
Published: July 2010

Catalytic splitting of the dimethylacetals of heptanal, 3‐cyclohexylpropanal, 3‐cyclohexylbutanal, 3‐phenylpropanal and 3‐phenylbutanal to corresponding unsaturated ethers was studied in a gas phase. Acid catalysts were employed in the study. Reaction conditions favorable to high splitting selectivity to ethers were suggested. The original acetals as well as synthesized unsaturated methylethers revealed characteristic odoring properties.
Characterization of unsupported molybdenum oxide—cobalt oxide catalysts
Authors: Halawy Samih A. , Mohamed Mohamed A. , Bond Geoffrey C.
Published: July 2010

Study of the thermal decomposition of mixtures of ammonium heptamolybdate (AM) and Co(NO3)2. 6H2O by TGA and DTA show that small amounts of Co (up to 5 mol % expressed as Co3O4) did not alter the way in which AM decomposed. Larger amounts of Co (10–90 mol% as Co3O4) reduced the number of steps from three to one, and in addition the transformation of Co3O4 to CoO was observed at c. 920°C. Endothermic peaks in DTA at 744–806°C, due to sublimation of MoO3, disappeared at higher Co contents. Samples containing 5, 10 and 30 mol% Co as Co3O4 showed exothermic peaks at 242–290°C due to formation of CoMoO4. The activation energies for the decompositions were calculated using the Coats—Redfern method from the TG results. XRD patterns of the samples calcined at 500°C indicated the formation of CoMoO4 for MoO3–30 mol% Co3O4, while those containing higher contents of Co3O4 (> 50 mol%) gave the typical XRD pattern of Co3O4. These results were confirmed by IR and TPR analyses. XPS analysis showed the presence of Mo(VI) in MoO3, but it was reduced to Mo(V) in the mixed samples. The binding energies for Mo 3d5/2 and Co 2p3/2 levels confirmed the formation of CoMoO4 in the sample MoO3–30 mol% Co3O4.
Studies of alizarine adsorption from solution on to aluminium hydroxide gels
Authors: Bakoyannakis Demetris N. , Stalidis George A. , Zamboulis Demetris , Jannakoudakis Demetris A.
Published: July 2010

Adsorption results of alizarine from ethanolic solutions on to aluminium hydroxide gels prepared by precipitation in pure and mixed aqueous and ethanolic media are presented. The gels had different specific surface areas and porous structures resulting from the nature of the solvent and the thermal treatment. Equilibrium took a long time to be established (about 9 h). In general, the higher the activation temperature of the gel the higher the adsorption capacity. The adsorbed amounts of alizarine on to the gels increased by increasing the adsorption temperature. The adsorption could be described equally well by the Freundlich and the Langmuir equations. Finally, the apparent enthalpy of the adsorption indicated an activated endothermic chemisorption.
Kinetics of metal ion exchange in iminodiacetic resins at low concentrations
Authors: Fernández A. , Suárez C. , Díaz M.
Published: July 2010

The kinetics of metal exchange processes with iminodiacetic chelating resin, which occurs with metal concentration change, has been studied. Mechanisms of rate control were analyzed, and diffusivities determined from experiments in batch solutions with decreasing metal concentrations, following the unreacted core model. Metal exchange in binary and ternary systems are analyzed and diffusivity variations of these systems discussed in terms of reaction fronts. The influence of temperature was also studied and energies of activation determined.
Modelling and application of the continuous impinging streams reactors in liquid—liquid heterogeneous reactions
Authors: Sohrabi Morteza , Kaghazchi Tahereh , Yazdani Farshad
Published: July 2010

The two phase mononitration of toluene, as an example of liquid—liquid reactions, has been studied in a continuous impinging streams reactor (CISR). The extent of reaction under different experimental conditions has been determined. A comparison has been made between the performance capability of the CISR and that of the continuous stirred tank reactor (CSTR). Under identical conditions, including mean residence time, temperature, feed compositions and phase ratio, the CISR has shown a higher efficiency. Finally, a stochastic model, based on Markov processes, has been developed for the reaction system which describes the flow pattern and the residence time distribution (RTD) in the reactor.
Studies of pressure build‐up due to particle deposition in a micro‐capillary with the use of three‐dimensional trajectory analysis
Authors: Arshad A. , Rahman M. S. , Rahman S. S.
Published: July 2010

A model is proposed to predict the increase in pressure drop in a micro‐capillary due to the particle deposition. Collection efficiency was estimated from three‐dimensional (3D) trajectory analysis which is based on mass balance and considers dispersion forces (London‐van der Waals), hydrodynamic forces (gravity and drag), and electrical force (electrical double layer). An exponential function introduced to 3D trajectory analysis accounts for the effects of fluid velocity on the particle capture probability. Validity of the model is tested experimentally by circulating a 1000 ppm bentonite suspension at different flow rates through a micro‐capillary of diameter 100 μM. Experimental evidence indicates that the 3D trajectory analysis is limited to a few conditions of particle deposition in a micro‐capillary.
Mechanism of phosphate interaction with two reference clays and an anatase pigment
Authors: Malati Mounir A. , Fassam Robert A. , Henderson Ian R.
Published: July 2010

The adsorption of phosphate by well‐characterised kaolin, mica or anatase followed the Langmuir isotherm. At pH values below the point of zero charge of each powder, adsorption was endothermic. A ring closure mechanism involving two adjacent adsorption sites would increase the entropy of the system compensating for the endothermic enthalpy change.
Liquefaction of cellulosic wastes: III. Production, characterization and evaluation of pyrolytic oils
Authors: Gharieb Hussein Kh. , Faramawy Sami , El‐Amrousi Fawzi A.
Published: July 2010

Liquefaction of municipal solid wastes has been achieved in an atmosphere of hydrogen gas and in the presence of boric acid which catalyzes the pyrolysis reaction. Two petroleum distillates, namely gas oil and residual fuel oil, were used as carrier media of solid refuse. The yield of pyrolytic oil was studied as a function of different operational conditions (temperature, pressure of hydrogen, carrier oil medium and concentration of boric acid). Hydrocarbon constituents of the oil mixtures, produced by liquefaction of cellulosic wastes slurried in fuel oil, were investigated by means of gas chromatography. It was found that the oil mixture, obtained at optimum reaction conditions, showed pronounced occurrence of low hydrocarbons in the range C3‐C15 as compared with the original fuel oil and the oil resulting from the pyrolysis of carrier oil without solid refuse. The residual pyrolytic char exhibited catalytic activity towards hydrocracking. It was suggested that the activity of char is due to the presence of transition metals as evidenced by an electron dispersion system (EDS). The hydrocracking activity of char seemed to be dependent on the operational conditions of the liquefaction. Multiple analytical parameters including API gravity, calorific value, total acid number and wt% of residue over 450°C were used to evaluate the oil mixtures produced as a petroleum crude oil. Carrier oils, particularly fuel oil, seemed to be highly modified in the course of the pyrolysis process. Also, the oil mixtures produced were distinguished from the original carrier oils by a considerably higher acidity due to association with oxygenated compounds which could be derived from cellulose macromolecules.
The osmometry of high polymers. I. Technique of osmometry
Authors: Cleverdon D. , Laker D.
Published: July 2010

Points of technique in the use of the Fuoss‐Mead osmometer, as modified by Masson and Melville, are discussed. In particular, a new criterion is described for the impermeability of the membrane to solute. Older criteria are critically reviewed. Problems of extrapolation of reduced osmotic pressure v. concentration curves are considered, and tentative explanations given for the negative slope sometimes observed.
Design of packed distillation columns. II. Operating vapour rates for packed distillation columns
Authors: Hands C. H. G. , Whitt F. R.
Published: July 2010

Relatively simple correlations of the important variables associated with allowable vapour rates in packed columns are presented. These are similar to those already used for the same purpose in connexion with plate columns. The suggested method of calculation of limiting velocity is simpler than those methods derived from correlations of a more complex type which are described in the literature on packed columns; it is nevertheless adequate for preliminary design of columns operating at atmospheric pressure or below.
Orientation problems. V. The nitration of the isomeric tolylsuccinimides
Authors: Evans W. H. , McGookin A.
Published: July 2010

It is shown that 2‐ and 4‐tolylsuccinimides, on nitration, form derivatives where the nitro groups occupy positions meta to the acylamino group, whereas 3‐tolylsuccinimide nitrates ortho‐para to the acylamino group; hence the methyl radical is the directing agent in these compounds.
The determination of free sulphur in vulcanizates by a polarographic method
Authors: Poulton F. C. J. , Tarrant L.
Published: July 2010

Using a buffered pyridine electrolyte, sulphur gives a regular polarographic wave suitable for its quantitative determination. A method based on this principle has been developed for the determination of ‘true’ free sulphur in rubber. The method has been compared with gravimetric and volumetric processes, and found to give slightly lower results than either of these, since sulphur combined in any form in the acetone extract is not included. It is particularly suited to routine replicate determinations as it is considerably quicker than older methods.
A spinning‐band column for vacuum fractionation of fatty‐acid esters
Authors: Williamson L. J.
Published: July 2010

A spinning‐band column which is specially adapted for the vacuum fractionation of fatty‐acid esters is described. Plate‐efficiency tests carried out at 760 mm. and in the range 3.0‐0.5 mm. show that the lowest value for the H.E.T.P. is 2.64 cm. at atmospheric pressure, this value increasing at the lower pressures. Distillation curves for ester mixtures show that the column is very suitable for analytical ester fractionation at pressures of the order of 1 mm.
Conversion of the simple electric furnace to precision high‐temperature maintenance
Authors: Warren D. R.
Published: July 2010

A simple and inexpensive method adaptable to most electric furnaces of reasonable internal dimensions is described. The furnace is converted into an air‐bath of very quick response, controlled with a simple and easily adjustable form of gas‐expansion thermostat. High temperatures may be maintained with very small fluctuation, and trouble from temperature gradients made negligible.
Azeotropic distillation apparatus
Authors: Raper D.
Published: July 2010

The paper describes an apparatus embodying, in a single unit which can be assembled in a few minutes, all the components necessary to condense, separate automatically and return the solvent and take off the water in azeotropic distillations.

The apparatus is suitable for reactions on any reasonable scale using various solvents lighter or heavier than water. Difficulty has been experienced with benzene, but means are suggested for overcoming it.
Film resistances in rectification
Authors: Chari K. S. , Storrow J. Anderson
Published: July 2010

Attempts have been made to analyse data from rectification in a wetted‐wall column in terms of postulated equations for film values of the height of a transfer unit (HTU) values. Discrepancies found in some of the correlations are no greater than are to be expected from our lack of knowledge of physical characteristics of the binary mixtures, notably of the diffusion coefficient in the liquid phase.
P‐aminobenzenesulphonylphenylcyanamide (N4‐cyano‐sulphanilide) and related compounds
Authors: Kurzer F.
Published: July 2010

Extension of the general method for the preparation of sulphonylcyanamides by the interaction of arylureas and aromatic sulphonyl chlorides has given p‐aminobenzenesulphonylphenylcyanamide by two routes. A number of related substituted sulphonamides of this type are also described. Migliardi and Tappi's claim to have obtained sulphonylureas from as‐diarylurea and arylsulphonyl chlorides could not be substantiated, the expected diarylcyanamides being obtained instead under the conditions of the present synthesis.

Attempts to extend to arylsulphonylarylcyanamides the general reaction of converting cyanamides to thioureas by the addition of hydrogen sulphide were unsuccessful.
The use of ethyl silicate in providing heat‐resistant coatings of aluminium on steel
Authors: Tolley G.
Published: July 2010

The doping of sprayed aluminium with ethyl silicate has been found to give a heat‐resistant coating which needs no heat treatment before putting into service. This coating is compared with aluminizing, and the relative protection given by these two coatings to mild steel from 700° to 950° C. has been determined.
Synthesis of 3‐ and 4‐methoxystyrenes
Authors: Sulzbacher Max
Published: July 2010

Various methods for the synthesis of 3‐ and 4‐methoxystyrene were studied. The decarboxylation of the corresponding methoxycinnamic acids was effected by means of anhydrous copper sulphate in quinoline solution with an improved yield.
The analytical examination of plasticizers obtained from polyvinyl chloride compositions
Authors: Haslam J. , Soppet W. , Willis H. A.
Published: July 2010

Methods which have proved useful in the chemical and infra‐red examination of plasticizers used in polyvinyl chloride (PVC) compositions are summarized. Information is given about the method of isolation of the plasticizer and the qualitative tests which may be applied. On the quantitative side attention is given to the saponification value and the determination of phthalate, phosphate and chlorine. Methods which have proved useful in the isolation of the alcohols derived from ester‐type plasticizers are described.

The infra‐red spectra of 19 common plasticizers are presented and the use of these spectra in the identification of plasticizers, and the qualitative and rough quantitative analysis of plasticizer mixtures is described. The examination by infra‐red spectroscopy of extracts from plasticizers, such as alcohols and unsaponifiable material, is described as an aid to identification of plasticizer mixtures.
Sulphonated cross‐linked polystyrene: A monofunctional cation‐exchange resin
Authors: Pepper K. W.
Published: July 2010

Recent improvements in the performance of ion‐exchange resins are illustrated by an account of the preparation and properties of sulphonated cross‐linked polystyrene. The copolymerization of styrene and divinylbenzene (DVB) in bead form is described. Cross‐linked polystyrene has been sulphonated by heating the copolymer with concentrated sulphuric acid at 100°c. in the presence of silver sulphate. After a time depending on the particle size and DVB content of the copolymer, the exchange‐capacity of the product attains a limiting value which corresponds to the formation of a monosulphonic acid. Sulphonated cross‐linked polystyrene is a hygroscopic gel; its swelling and shrinkage in water and aqueous solutions are markedly dependent on the degree of cross‐linking. The cation‐exchange properties of the resin are consistent with those expected of a monofunctional, strongly acidic material. The influence of the extent of cross‐linking on the relative affinity‐coefficients and rates of exchange of sodium and hydrogen ions are indicated.
A method for the quantitative estimation of copper with particular reference to proofed jute fabrics
Authors: Macmillan W. G. , Das P. C.
Published: July 2010

Copper in the presence of excess ammonia can be estimated volumetrically by titration at the boil against a glucose solution previously standardized with a copper solution under identical conditions. The method was found useful for the estimation of copper in proofed jute fabrics.
Design of packed distillation columns. IV. An empirical method for the estimation of column height using the H.E.T.P. concept
Authors: Hands C. H. G. , Whitt F. R.
Published: July 2010

Published results on packed columns and some additional original data on semi‐technical columns filled with Raschig rings are presented in a form permitting correlation of H.E.T.P. values with packing diameter, rate of liquid flow and liquid viscosity.
Formaldehyde condensations with phenol and its homologues. XI. The preparation of 2‐hydroxymethyl‐3:5‐dimethylphenol by a new general method
Authors: Finn S. R. , Musty J. W. G.
Published: July 2010

In Part V of this series, it was shown that the reaction of formaldehyde with 3:5‐dimethylphenol could result in the formation of either the p‐monoalcohol or the 0‐0′‐dialcohol, according to the reaction conditions.

The 0‐monoalcohol (2‐hydroxymethyl‐3:5‐dimethylphenol) has now been prepared from 2‐dimethylaminomethyl‐3:5‐dimethylphenol by conversion with acetic anhydride to 1‐acetoxy‐2‐acetoxy‐methyl‐3:5‐dimethylbenzene, followed by reduction of the latter with lithium aluminium hydride. This process may be expected to provide a general method for the preparation of phenolic alcohols from the parent phenols.

The structure of the 0‐alcohol has been confirmed by reduction of the corresponding aldehyde with lithium aluminium hydride.
Synthesis of molecular units for rational synthesis of phenol‐formaldehyde and allied resins. I. Synthesis of resoles, dihydroxydiphenylethanes, and dihydroxydiphenylpropanes
Authors: Carpenter A. T. , Hunter R. F.
Published: July 2010

The rational synthesis of polycondensation individuals produced during the formation of phenol‐formaldehyde and allied resins by reactions leading to unequivocal structures has been begun. Three resole structures have been synthesized by methods which offer extension to other intermediates : (i) 2 : 4′‐Dihydroxy‐5‐hydroxymethyldiphenylmethane was synthesized by application of a lithium‐exchange reaction with n‐butyl‐lithium to 5‐bromo‐2 : 4′‐dihydroxydiphenylmethane by way of the 5‐carboxy‐2 :4′‐dihydroxy‐derivative which was reduced to the required compound by lithium aluminium hydride; (ii) 2 : 2′‐dihydroxy‐3 : 5‐bishydroxymethyldiphenylmethane was synthesized from 3 : 5‐dibromo‐2 : 2′‐dihydroxydiphenylmethane by way of 3 : 5‐dibromo‐2 : 2′‐dihydroxy‐3′: 5′‐bishydroxymethyldiphenylmethane, which on controlled reduction with palladium‐hydrogen furnished the required bishydroxymethyl compound; (iii) 2:4: 6‐trishydroxymethylphenol was obtained by reduction of ethyl hydroxytrimesate by lithium aluminium hydride in dioxan.

As a contribution towards the problem of ‘ cross‐linking ’ in phenolic resins, I : 2‐di‐(p‐hydroxy‐phenyl)ethane, I: 2‐di‐(o‐hydroxyphenyl)ethane, and I‐o‐hydroxyphenyl‐2‐p‐hydroxyphenylethane, in which the phenolic nuclei are separated by an additional methylene group, have been rationally synthesized with a view to comparison of their reaction with formaldehyde with that of the corresponding dihydroxydiphenylmethanes. The corresponding isomeric dihydroxydiphenylpropanes have also been prepared for investigation of the effect of insertion of a further methylene group between the phenolic nuclei.
The kinetics of continuous reaction processes: Application to polymerization
Authors: Denbigh K. G.
Published: July 2010

The paper discusses the general principles of the kinetics of reactions as carried out in the two main types of continuous process. Comparison is made with the corresponding batch system with regard to the necessary volume of reaction space. It is shown that a correct choice of the type of process can sometimes be used to increase the yield of a reaction. The application of these principles to polymerization is described in outline.
Polymerization of isobutene by boron trifluoride
Authors: Evans Alwyn G.
Published: July 2010

The polymerization of isobutene by BF3, requires a co‐catalyst. The true catalyst for this polymerization is the complex of the co‐catalyst with the BF3. The initiation, propagation and termination steps of this process are discussed.
The chemistry of phenolic resins and the processes leading to their formation
Authors: Zinke Alois
Published: July 2010

The paper presents first a review of the work on phenolic resins done by Euler and his co‐workers, by Hultzsch and by Zinke and his team, and of the importance of this work for the knowledge of the hardening process. More recent research work of Zinke and his co‐workers, especially on cyclic polynuclear phenols is also described. There is a short discussion of the chemistry of novolaks and of the work of Ziegler. Results of research on the hexamine‐hardening process are also discussed.
Recent developments in x‐ray diffraction studies of high polymers
Authors: Bunn C. W.
Published: July 2010

Examples of preferred ‘tilted crystal’ orientations in fibres during the early stages of drawing and also during contraction on heating are described. The crystallographic direction of tilt in drawing is, in the examples studied so far, not the same as the direction of tilt in relaxation. Tilted‐crystal X‐ray diffraction patterns give very valuable aid in the determination of the crystal structures of high polymers.

The ability of high polymers to crystallize depends on geometrical regularity of molecular structure; chemical or stereochemical irregularity prevents crystallization unless the alternative groups of atoms are similar in size and shape.

The determination of the proportions of crystalline and amorphous material in polymer specimens by the X‐ray diffraction method is discussed. The experimental requirements and the underlying theoretical assumptions are pointed out.

A reversible transition of a novel type has been detected in polytetrafluoroethylene: the onset of partial disorder in the crystals at room temperature, 300° c. below the melting point.
Practice of osmometry: Its contribution to the characterization of a high polymer
Authors: Cleverdon D.
Published: July 2010

Osmometers are reviewed, together with the current opinion concerning thermodynamic investigations arising from their use. The validity of osmotic pressures extrapolated to infinite dilution to provide one of the fundamental molecular weight averages is emphasized. The nature of distribution curves constructed from a single type of molecular weight average is discussed. The number‐average and viscosity‐average distribution curves of a commercial polystyrene are compared. The number‐average molecular weights are also used to compare the Beall procedure of treating fractionation data with the classical one. The Beall procedure indicates the presence of a very high molecular weight ‘tail’ to the distribution, for whose existence there is ancillary evidence.
Studies on birefringence of macromolecular solutions
Authors: Sadron C.
Published: July 2010

A large amount of work has been done during recent years in order to find out the main properties of submicroscopic particles dispersed in a liquid from the mean physical properties of their solutions, such as viscosity, light‐scattering power, osmotic pressure, and Brownian diffusion.

In general it is necessary to study several of these properties before predicting mass, shape, dimensions, mechanical or optical characters of the particles.

This paper gives a brief survey of the results that may be obtained from the study of the double refraction which can be induced in a macromolecular solution by application of a proper field of orientation, namely a hydrodynamical or an electrical field. The effect of a magnetic or of an ultrasonic field is not discussed in this paper because of the uncertainty of the interpretation of the experimental results so far obtained.

The case of a hydrodynamical field (stream double‐refraction) has actually been previously studied more thoroughly; it is considered in this paper, but some results obtained in the second case (Kerr effect), which seem to be very promising, will also be given.
Mechanism of the degradation of polyamides
Authors: Achhammer Bernard G. , Reinhart Frank W. , Kline Gordon M.
Published: July 2010

Films of polyamides were exposed to heat, ultra‐violet radiant energy, and different atmospheric conditions. The degradation products were collected in some cases and analysed by mass‐spectrometric techniques. The unexposed and exposed specimens were examined by the following techniques to obtain information concerning the changes in chemical and physical structure of the polymer: infra‐red absorption, ultra‐violet absorption, viscosity of solutions, measurement of dielectric constant and dissipation factor, photomicrography, X‐ray diffraction, electron microscopy, and effect of organic liquids. In addition, pyrolysis studies were made and some physical properties were determined. The results of the investigation show clearly that no single method gives a complete picture but that the results from several of the methods give an insight into the degradation mechanism. The general course of the degradation of polyamides may be described as follows : (I) splitting of the polymer chain at the C‐N linkages; (2) changes in degree of crystallinity or local order; and (3) loss of dipole‐associated plasticizers.
Corrosion experiments with gaseous boron trifluoride
Authors: Hudswell F. , Nairn J. S. , Wilkinson K. L.
Published: July 2010

A number of constructional materials—metals, alloys and miscellaneous compounds—which may be required to come into contact with boron trifluoride were subjected to treatment with this gas under carefully controlled conditions.

The materials were examined by bringing into contact with gas at an original fixed pressure of about 25 cm. of mercury, and at temperatures up to 200° c. The extent of the reaction, if any, was shown by the alteration of the gas pressure over the sample.

Many of the materials examined showed a high resistance to chemical attack by boron trifluoride. The following materials can be safely used in apparatus for handling dry boron trifluoride : stainless steel, mild steel, copper, nickel, Monel metal, brass and aluminium, the more noble metals up to at least 200° c.; Pyrex glass is also suitable up to about 200° c.; Araldite cement, fired pyrophyllite and polytetrafluoroethylene may be used up to 80° c. Great variation was shown by the others in the miscellaneous group of compounds.
Some factors affecting the useful rates of reaction in the industrial polymerization of styrene
Authors: Elly Joyce , Haward R. N. , Simpson W.
Published: July 2010

The current values for the velocity constants for styrene polymerization are used to calculate the rates at which polystyrenes of particular viscosities can be prepared. It is shown that optimum temperatures should exist where there is the highest rate of formation of a polymer of specified viscosity. However, these rates can be exceeded in the later stages of bulk polymerization or in emulsion polymerization where the bimolecular termination reaction is restricted by a high‐viscosity medium or by compartmentalization. On the other hand, reduction‐activated bulk systems fall into line with the general theory proposed.
Polyethylene‐structure, crystallinity and properties
Authors: Richards R. B.
Published: July 2010

By polymerizing ethylene under various conditions of temperature and pressure a wide range of polymers may be made including oils, greases, soft and hard waxes and plastics both softer and harder than the familiar type of polymer used for electrical insulation and film. Some of these variations in properties are caused by changes in average molecular weight. Variations among samples of the same molecular weight are, however, observed; these cannot normally be attributed to changes in distribution of molecular weight but are due to differences in the structure of the polymer molecule. Many of the properties of the solid polymer are determined by the degree of crystallinity. This is affected little by average molecular weight and distribution of molecular weights, but is dependent to a major extent by the degree of chain branching. The measurement of chain branching and its effect on crystallization is discussed and the influence of average molecular weight and molecular structure on a number of properties, including cracking in organic liquids, is described. The importance of the arrangement of the crystalline regions is stressed.
Itaconic acid. II. The condensation of itaconic anhydride with some conjugated olefins
Authors: Rivett D. E. A.
Published: July 2010

The Diels‐Alder condensation of itaconic and citraconic anhydrides with various conjugated olefins is described.
Catalytic hydrogenation of 3:4‐epoxido‐4‐methyl‐2‐pentanone
Authors: Bergmann Ernst D.
Published: July 2010

Catalytic hydrogenation of 3:4‐epoxido‐4‐methyl‐2‐pentanone with Raney nickel in isopropanol attacks the epoxide ring before the carbonyI group: The two isomeric forms of 4‐methylpentane‐2 : 3‐diol have been obtained together with methyI isobutyI ketone, a product of the combined hydrogenation and hydrogenolysis of the starting material.
The influence of carbon smokes on the dew‐point and sulphur trioxide content of flame gases
Authors: Whittingham G.
Published: July 2010

Dew‐point and chemical methods of analysis have been used to investigate the effect o carbon smokes on the sulphur trioxide content of flame gases. As the quantity of smoke increases from zero the conductivity‐temperature characteristics of condensed films of acid become complex owing to the deposition of electrically conducting carbon on the dew‐point element. Conductivity measurements indicate that deposited carbon and sulphuric acid films react at temperatures above about 140° c. Analytical determinations show that the sulphur trioxide content of the gases is decreased in the presence of carbon. Suggestions are made of the means whereby the sulphur trioxide content is lowered.
A mechanical foam‐generator for use in laboratories
Authors: Fry J. F. , French R. J.
Published: July 2010

A description is given of the development and performance of a variable foam‐generator for use in laboratory experiments with mechanical foams for fire‐fighting.

The generator is designed to provide accurate control of the character of the foam as measured by its expansion factor and its ultimate shear strength.

The apparatus has been called a mechanical foam‐generator to distinguish it from equipment in which the disperse phase of the foam is generated chemically; air is the gas most commonly used for the disperse phase, but other gases may be used if required.
A laboratory method of comparing the efficiencies of fire‐fighting air‐foams
Authors: Fry J. F. , French R. J.
Published: July 2010

A description is given of apparatus for comparing the efficiencies of different, mechanically‐produced, fire‐fighting foams by measuring a ‘figure of merit.’ The figure of merit used is a dimensionless index intended to take into account the ability of the foam to flow over the surface of an inflammable liquid, its resistance to destruction by contact with the liquid and its resistance to destruction by fire. Examination of the foam is carried out under standard conditions and the figure of merit is then defined as the ratio between the rate of coverage of the liquid surface by the foam and the rate of destruction of the foam when the liquid is allowed to burn.

Figures of merit have been obtained for a number of different fire‐fighting foams on petrol.
Determination of the particle size of fine powders, with particular reference to kaolins
Authors: Rossi Corrado , Baldacci Ruffo
Published: July 2010

The sedimentation curves for suspension of kaolins from Central Europe, Italian bentonites and clays have been obtained by using a hydrostatic balance provided with a normal plunger. Investigations undertaken to establish the accuracy of the method and the theoretical calculation of the sedimentation curves are briefly described. The possibility of applying Stokes' law to the mass settling of kaolins is also discussed. The authors wish to emphasize (a) the possibility of determining the average diameter of powder particles by means of the tangent to the curve at zero time, and (b) the possibility of deducing from experimental sedimentation curves both the curves relating to size distribution (the number of particles as a function of equivalent diameter) and the cumulative curves (the percentage by weight of particles having dimensions smaller than one determined equivalent diameter).

When carrying out sedimentation measurements, particularly with kaolins, it is possible to obtain regular curves only when conditions are such as to avoid flocculation. This result is achieved by adding suitable electrolytes in quantities which determine the smallest sedimentation volume.

The average equivalent diameters of the powders examined were deduced from such sedimentation curves.

Statistical measurements of dimensions made by direct microscopic observations have been carried out on two kaolins from Central Europe, resulting in average values which agree very closely with those calculated from the sedimentation curves.

Cumulative curves of the usual type have been obtained from the densimetric curves of sedimentation.
The application of lithium aluminium hydride to the preparation of some amino‐alkanols
Authors: Avison A. W. D.
Published: July 2010

The preparation of several amino‐alkanols by the reduction with lithium aluminium hydride of certain ‘amic’ acids and their esters, aromatic keto‐acid amides and nitriles is described.
The transmission of light through suspensions
Authors: Lothian G. F. , Chappel F. P.
Published: July 2010

Measurement of the optical transmission of a suspension of small particles is of considerable importance, e.g. for determination of particle size. In certain conditions interpretation of measurements is simple, i.e. when it may be assumed that the particles behave as an opaque screen of area equal to the total projected area of the particles in the beam. In general, however, the projected area must be multiplied by a factor K, known as the total scattering coefficient, which can have values between o and about 5.

The present paper reviews the values of K as a function of the wavelength λ of the incident light, the refractive index, absorption and radius (a) of the particles, and the angular size of the detector used in an experimental arrangement.

Attention is confined to spherical particles. By using elementary diffraction theory it is possible to obtain a physical picture of the reasons for the variation of K from the value I expected from geometrical optics. Exact methods of calculation are discussed, following Airy, Mie and Rayleigh for the respective cases a≫λ, a∽λ, a≪; some typical results from published calculations are quoted and reviewed, and optimum conditions for measurement are suggested.
ACenaphthylene: Its polymers and copolymers
Authors: Kaufman M. , Fowler Williams A.
Published: July 2010

Details of the laboratory and semi‐technical‐scale preparation of acenapththylene by the vapour‐phase dehydrogenation of acenaphthene are given.

Polymerization of acenaphthylene is discussed together with some of the properties of the plasticized polymer. Copolymers with styrene have been studied in their preparation by bulk, bead and emulsion processes and some of their properties have been related to composition and mode of polymerization. The availability and economics of the monomer are considered briefly.
Organic adsorbents from indian tannins. I. Preparation, activation and relative adsorptive power
Authors: Bhatnagar M. S. , Nigam P. C.
Published: July 2010

Many workers have described costly phenol‐formaldehyde or amine‐formaldehyde resins for ion‐exchange. Tannins of the catechol type can also be used for the same purpose. In a previously published communication (Bhatnagar & Singh, 1950), it has been shown that katha (the edible material used in betel leaves) yields on sulphonation products which exhibit calcium and magnesium exchange. More resins from katha and cutch have now been prepared and their adsorptive properties have been studied.

The products obtained by sulphonation of katha and cutch and subsequent condensation with formalin are found to adsorb about 95% and 65% fatty acids respectively from centimolar solutions. The resins obtained by mere sulphonation show little adsorption of acids. The products obtained by direct condensation of katha and cutch with formalin exhibit 15% and 0% adsorption respectively of benzoic acid. On the other hand, resinous products obtained by incorporation of katha and cutch in phenolic resins prepared using ammonia as a catalyst show high adsorption values, namely, 55% and 70% respectively of formic acid. The adsorptive properties of standard resins, e.g. Amberlites, Zeo‐karbs, etc., have also been studied. The study reveals that the prepared resins are comparable with standard resins.
Plate‐efficiency correlation in distllling columns and gas absorbers
Authors: Chu Ju Chin , RichardDonovan J. , Clifford Bosewell B. , Charles Furmeister L.
Published: July 2010

Two methods are developed for the rstimation of plate effiacncy in distilling colmuns and gas
absorbers. The fint method, which is the more rigorous, deals with the correlation of local Murphree plate efficiency, and a find working formula is derived.

It is interesting to note that surface tension has no direct effect in determinin the value of plate efficiency, but enters, together with density of liquid and vapour, slot width and height, temperature and pressure of the system, into the expression for the calculation of critical flow rate which divides flow into turbulent and streamline region for choosing the right equation to calculate the bubble size which, in turn, is an important factor determining plate efficiency.

The mold ratio of liquid to vapour rate, L V, is introduced durig either the axlrrenion of local Murphree plate efficiency into overall plate efficiency or the calculation of actual number of plates through the plate‐to‐plate method with Murphree plate efficiency. The ratio L/V might also enter into a function as a correction factor for the bubble‐size calculation if the column is operated at extremely high value of the L/V ratio.

The second method correlates the overall plate efficiency of fractionating columns with L/V ratio, effective submergence, relative volatility of key components and viscosity of the feed.

Two equations are derived which, although more empirical, represent a convenient route to compute the actual number of plates in distilling columns or gas absorber.
The presence of the persulphuric group in the molecule of nitrous vitriol associated with tower acid
Authors: Guareschi Pietro
Published: July 2010

Evidence is given for the existence of a compound known as nitropersulphuric acid. This is claimed to be present in acid obtained from a chamber plant which enables oxidation of sulphur dioxide to take place in the liquid phase, and without the liberation of nitrous gases. Analytical tests are outlined which prove the existence of such a compound.
Identification of the cementing material in a light‐weight sand‐lime block
Authors: Taylor H. F. W.
Published: July 2010

The cementing material of a commercial light‐weight sand‐lime block has been shown by analytical and X‐ray investigations to be calcium silicate hydrate (I) (for nomenclature see Taylor, 1950), of approximate composition 1.28CaO, SiO2, 2.05H2O. The X‐ray powder data are in close agreement with those of laboratory preparations. This result shows that calcium silicate hydrate (I) is capable of being formed under the conditions appertaining in a paste. It therefore appears possible that the cementing agents of sand‐lime bricks in general, and also of hydrated Portland cement, are composed of the same, or a very similar compound.
A new method for the interpolation of ternary vapour‐liquid equilibrium data
Authors: Herington E. F. G.
Published: July 2010

A method of plotting the logarithms of the activity coefficients of each component in a ternary system is described which takes advantage of information on the three binary systems. For a ternary system A, B, C the values of log γA against xc, log γB against xc, and log γc against xB are plotted for a constant value of xB/(xB + xc), where xA, xB and xc are the mole fractions of the three components in the liquid. If the whole ternary diagram is to be explored these plots are carried out for a series of values of the parameter xB/(xB + xc). A method of interpolation is described and thermodynamic tests for the consistency of the resulting plots are developed. The use of the procedure is illustrated by application to published information on the system acetonitrile (methyl cyanide)‐trichloroethylene‐water.
The preparation of anhydrous lanthanon chlorides by high‐temperature chlorination of monazite
Authors: Hartley F. R.
Published: July 2010

The reaction between monazite, chlorine and carbon has been investigated at temperatures above the melting point of the mixed lanthanon chlorides. Conditions have been established, on a laboratory scale, for recovering over 85% of the lanthanons as anhydrous chlorides. At temperatures over 900° c. these are virtually free of thorium chloride and phosphorus compounds, which volatilize together with impurities such as iron, aluminium, chromium and titanium chlorides.

The nature of the volatile products has been examined and particular reference is made to the evolution of elementary phosphorus. The thermodynamics and mechanism of the reactions have been discussed.
Studies in the coal‐tar bases. IV. Lutidine and collidine fractions
Authors: Coulson E. A. , Hales J. L. , Holt E. C. , Ditcham J. B.
Published: July 2010

The lutidine and collidine fractions of coal‐tar bases contain as predominating constituents 2:5‐, 2:4‐, and 2:3‐lutidines, 6‐ethyl‐2‐methylpyridine, 3‐ethylpyridine, and 2:4:6‐ and 2:3: 6‐collidines. The four first‐mentioned bases occur in commercial ‘2: 4–2: 5‐lutidine.’ 3‐Ethylpyridine has been isolated from a coal‐tar collidine for the first time. All these bases form maximum‐boiling‐point azeotropes with phenol, some of which can be used to effect the concentration or separation of individual bases: 6‐ethyl‐2‐methylpyridine in particular is readily obtained in this way. 2:5‐Lutidine forms a high‐melting complex with phenol which can be applied to the separation of a high proportion of this base from mixtures in which it occurs.

Infra‐red absorption spectroscopy provides convenient methods for the analysis of picoline, lutidine and collidine fractions.
An improved automatic mercury‐distillation apparatus
Authors: Yorke S. G.
Published: July 2010

A vacuum mercury still is described, the operation of which is unaffected by normal changes of atmospheric pressure. An air‐leak system, operating in conjunction with a vacuum pump, is used to feed droplets of mercury to the still from a reservoir open to the atmosphere. Automatic protection against failure of any part of the system is provided by making appropriate sections of the mercury columns part of the control circuit.
Determination of the ‘extinction coefficient’‐particle size relationship for spherical bodies
Authors: Rose H. E.
Published: July 2010

In the present paper an account is given of an experimental investigation into the ‘extinction coefficient’–particle size relationship for small spherical particles.

An accurate knowledge of this relationship is essential if the photo‐extinction method of powder‐size analysis is to be applied with the highest accuracy of which the technique appears to be capable; an insufficient knowledge of this relationship is probably responsible for the introduction of the large margin of uncertainty at present encountered in the application of the method.

In the present investigation efforts have been made to eliminate the errors usually encountered in the experimental determination of the relationship and the experimentally determined curve appears to be in good agreement with the limited theoretical results available.
A method for determining low concentrations of oxygen in gases
Authors: McArthur I. A.
Published: July 2010

The method was developed primarily to determine the oxygen content of a plant gas, containing 99% carbon dioxide but is also suitable for use with other gases, e.g. hydrogen, nitrogen and carbon monoxide. The amount of oxygen is measured by passing the gas through a known volume of dilute acidified chromous chloride solution and determining the resultant change in chromous ion concentration. The method can be applied to determine concentrations of oxygen over a wide range. Its accuracy has been proved over the range of 5–55 parts per million.
Organic fluorides. X. The formation of fluoro‐oils and resins by the polymerization of hydrofluorocarbons with fluorine
Authors: Smith F. , Stacey M. , Tatlow J. C. , Dawson J. K. , Thomas B. R. J.
Published: July 2010

Fluorine diluted with nitrogen reacted with hydrofluorocarbons such as benzotrifluoride, in solution in fluorocarbons or in pentachloroethane, to give high‐boiling products, presumably from condensation reactions proceeding simultaneously with fluorination. Treatment of these products in the liquid phase first with fluorine under more drastic conditions, and then with silver difluoride, gave a series of perfluoro‐lubricants and resins.