bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactions of aminoalkyl silicates with oxirane compounds
Authors: Emblem H. G. , Hurt N. A.
Published: July 2010

Reactions between several aminoalkyl silicates and oxirane compounds are described. Ethyl (ethanolamine) polysilicate, prepared from ethyl polysilicate and ethanolamine, reacts with propylene oxide to give products which gel when mixed with water. In contrast, products obtained by reacting monoethanolamine orthosilicate or 2‐aminobutyl orthosilicate with oxirane compounds are stable in aqueous solution. If the aminoalkyl silicate contains unsubstituted organic groups, a self‐condensation of the reaction product is possible. The properties of the various reaction products are given and related to present knowledge of the behaviour of organic silicates. The reaction mechanism is discussed in relation to the known reaction of amines with oxirane compounds. Possible stuctures of the products obtained in the self‐condensation reaction which can occur in compounds containing unsubstituted organic groups are considered.
Epoxidation of ethylenic linkages by chromic acid. I. Oxidation of 1,1,2‐triphenylpropene‐1 by chromic oxide
Authors: Moussa G. E.
Published: July 2010

The oxidation of 1,1,2‐triphenylpropene‐1 by chromic oxide in acetic anhydride gives 1,2‐epoxy‐1,1,2‐triphenylpropane with fission products and 2,3,3‐triphenylprop‐2‐en‐1‐al. The epoxide is relatively stable towards aqueous sulphuric acid.

Chromic acid in aqueous sulphuric acid brings about oxidative fission of the double bond together with the formation of the above unsaturated aldehyde.

A mechanism for the epoxidation of olefins in chromic acid is discussed.
The effect of cyclo‐octatetraene on radiation‐chemical reaction
Authors: Ellinger L. P.
Published: July 2010

Cyclo‐octatctraene is shown to have a powerful retarding effect on several radiation‐chemical reactions including the polymerisation of vinyl acetate, vinylpyrrolidone and styrene and the degradation of hydroxyethylcellulose in aqueous solution.
The composition and crystallography of an anhydrous calcium aluminosulphate occurring in expanding cement
Authors: Halstead P. E. , Moore A. E.
Published: July 2010

The existence of a compound of composition 4CaO,3A12O3, SO3 is confirmed and the structure, which has body‐centred cubic symmetry, is deduced to be of the ‘ultramarine’ type. The high‐temperature stability of the compound is discussed, together with its potential applications in an expanding cement.
Influence of some conditions of calcination on the reactivity of calcium sulphate hemihydrate
Authors: Ridge M. J. , Surkevicius H.
Published: July 2010

A study has been made of the influence of temperature and of some other conditions in the calcination of gypsum on the properties of the product. No anhydrite was detected in the product of still calcination carried out at temperatures up to 200°, but calcination at 143° and above in a rotary calciner leads to appreciable rates of transformation to anhydrite. The formation of anhydrite appears to be catalysed by water vapour, and initiated to some extent by friction of the grains.

The reactivity of the product of still calcination of the sample of gypsum studied appeared to be independent of the duration of calcinations taking more than 10 h., and was at a minimum for calcination at about 150°. The reactivity of the product of rotary calcination varied in a more complicated manner. In general, the higher the temperature of preparation the greater was the reactivity of hemihydrate. Anhydrite appears to offer favourable sites for the formation of gypsum nuclei and its formation tends to be associated with a more reactive product. However, it is evident that mechanisms other than the formation of anhydrite produce sites for the nucleation of gypsum and this matter is discussed.
The influence of pH on the surface characteristics of silica gel soaked in aqueous solutions
Authors: Dollimore D. , Heal G. R.
Published: July 2010

When silica gel is soaked in solutions of pH between 0.43 and 11.2 its surface characteristics are altered. The general effect is to diminish the surface area as measured by low‐temperature nitrogen‐adsorption. The original surface area of the silica gel was 685 m.2/g. and the largest diminution occurred on soaking at pH 11.2. when a product with an area of 328 m.2/g. was produced. Pore size distribution curves show a trend towards loss of smaller pores and growth of larger ones. The particle size of the various samples, as measured by hindered settling and sedimentation balance techniques, indicated a growth of particle size under those conditions where increase in the average radius of the pores was recorded. These effects are described in terms of movement of silica from large to small pores, and to the external surface, where it cements particles together.
Surface properties of hydrolysed titania. I. Titania prepared from titanium tetra‐alkoxides
Authors: Harris M. R. , Whitaker G.
Published: July 2010

Samples of active titania have been prepared by the hydrolysis with steam of several titanium tetra‐alkoxides under neutral ion‐free conditions, and their surface properties studied by nitrogen adsorption at − 195.8°. It is shown that for a series of normal alkoxides hydrolysed from solution in either benzene or the parent alcohol, the product has a stable surface area close to 300 m.2 g.−1, being porous with a mean pore radius of about 20 A. No appreciable ageing was observed except when the titania gel was kept in contact with the boiling mother‐liquor. By hydrolysis in acidic and basic media and subsequent alteration of the pH, a variation in pore size was obtained.
Selective ion‐exchanger based on a phenylfluorone derivative
Authors: Seidl J. , Štamberg J. , Hrbková E.
Published: July 2010

A new type of selective ion‐exchanger was prepared by condensation of resorcylfluorone with formaldehyde. The structure units of fluorone, retain their ability for binding germanium even after their incorporation into the three dimensional macrormolecular matrix. The ion‐exchange resin formed in this way sorbs germanium selectively even from concentrated solution of acids and salts, e.g. from azeotropic hydrochloric acid. The desorption of germanium can be carried out by elution with water. This procedure may be used for separating germanium from arsenic and iron (and from further elements) in chloric acid solution the germanium being finally isolated as dioxide in a very pure form.
The immersion wheel‐tracking test
Authors: Mathews D. H. , Colwill D. M.
Published: July 2010

The main features of the Immersion Wheel‐tracking test and its use as a laboratory tool in the study of bituminous binder/aggregate adhesion are described. The importance of various factors, including the procedure for preparing the test specimens, control of the temperature of the water bath and the effect of the depth of immersion of the samples in the bath are discussed. Finally, some consideration is given to the practical significance of the results of the test in relation to the stripping of binders from aggregates on the road.
REACTIONS IN HEATED LIME‐ALUMINA MIXTURES
Authors: Williamson J. , Glasser F. P.
Published: July 2010

Results of heating five lime‐alumina mixtures for 3–120 h. at temperatures from 1045° to 1405° are presented. The mixtures were prepared from mixtures of CaCO3 (calcite) and α‐Al2O3 and also from co‐precipitated hydroxide gels. Significant departures from equilibrium were noted. In general the gel mixtures approached the equilibrium state more rapidly. Unstable 5CaO,3Al2O3 was not detected. Previous interpretations of X‐ray diffraction patterns of heated lime‐alumina mixtures are shown to be in error. The mechanism of the reaction cannot be uniquely determined from a study of the bulk reaction products.
The promotion of dropwise condensation by montan wax. I. Heat transfer measurements
Authors: Watson R. C. H. , Birt D. C. P. , Honour C. W. , Ash B. W.
Published: July 2010

A hydrophobic surface has been produced on condenser tube surfaces by injection of montan wax and related chemicals into the‐condensing steam. The extent and duration of the increase in the overall heat‐transfer coefficient of the condenser, that results from the condensation of steam in discrete drops on the hydrophobic surface, have been measured. It is shown that the most successful dropwise condensation promoters are those waxes with the highest proportion of acidic groups, and that these are most effective when used with copper or copper alloy condenser tubes.
Extraction of lanthanons with alkali metal amalgams. II. A counter‐current process for the extraction of samarium or ytterbium
Authors: Barrett M. F. , Topp N. E.
Published: July 2010

A technique is described for the continuous extraction of samarium or ytterbium from rare earth concentrates. Extraction is carried out in a packed column by passing a solution of a lanthanon concentrate countercurrent to a dilute sodium amalgam. A samarium or ytterbium amalgam is formed which flows to a second column, where the rare earth is stripped from the amalgam with hydrochloric acid.

Factors controlling the efficiency of the process are discussed.
Dissolution rates of uranium dioxide sintered pellets in nitric acid systems
Authors: Taylor R. F. , Sharratt E. W. , De Chazal L. E. M. , Logsdail D. H.
Published: July 2010

The dissolution process for sintered uranium dioxide into nitric acid falls into two regimes of behaviour which depend on the overall transfer rate. The critical dissolution rate is approximately 8 mg. cm.−2 min−1, its precise value depending upon the solvent composition. Below this critical value there is a large degree of chemical kinetic control, the dissolution rate being proportional to the cube of nitric acid concentration, the experimental activation energy being 15 kcal. mole−1. Above the critical value the process appears to be controlled by the diffusion of a nitric acid species as the transfer rate is directly proportional to acid concentration with an activation energy of about 4 kcal. mole−1.

In addition, the reaction is autocatalysed by the nitrite product so that forced convection can reduce rates by a factor of four times, and nitrite neutralisers can reduce them by a factor of one hundred times.

To a first approximation the dissolution rate depends simply on the total nitrate concentration although polyvalent nitrates and, in particular, ferric nitrate, tend to accelerate the reaction.
Ultra‐violet spectroscopic determination of phenolic antioxidants in stabilised lanolin
Authors: Lee S. , Puttnam N. A.
Published: July 2010

An ultra‐violet spectroscopic method is described for the determination of the antioxidant Topanol OC (2,6‐di‐t‐butyl‐4‐methylphenol) in stabilised Lanolin. The determination is based on the corrected absorbance at 283.5 mμ and the interfering absorptions arising from the Lanolin are removed by compensation with a standard Lanolin solution.
Evolution of volatile hydrocarbons from coal
Authors: Girling G. W.
Published: July 2010

The products in the range C4 to C10 obtained from a series of coals by heating in stages from ambient temperature up to 700° have been analysed by gas‐liquid chromatography. Aliphatic and aromatic compounds are evolved even below 100°. The rates of evolution do not increase regularly with temperature, but show two distinct maxima. Coals of different rank, and different macerals of the same coal, are compared.
Reactivity of lime and related oxides. IX. Hydration of magnesium oxide
Authors: Glasson D. R.
Published: July 2010

Magnesium oxide samples differing widely in surface activity (specific surface 10–180 m.2 g.−1) have been ‘dry’ hydrated by exposure to water vapour at 22° and ‘wet’ hydrated by liquid water at 22° and 95°.

The rates of hydration differ considerably, the reaction generally proceeding inwards from the outside of each oxide crystallite by an advancing interface mechanism. Changes in surface area and crystal structure resemble those during the hydration of lime. The more active magnesias age (agglomerate) rapidly in both ‘dry’ and ‘wet’ hydrations, unless the relative water vapour pressures are low; even then, the very slow completion of the hydration ultimately produces considerable ageing.

The less active magnesias ‘dry’ hydrate slowly like the less active limes, with splitting of the larger original crystallites increasing the total number present. ‘Wet’ hydration at 22° proceeds with some ageing of the hydroxide, even during the earlier stages and this becomes much greater later. At the higher hydration temperature, 95°, the product ages more rapidly, but the much greater hydration rate produces a time lag in the recrystallisation of the newly‐formed magnesium hydroxide to its normal structure. Later, expansion splits the aged material as the recrystallisation is completed, with the hydration becoming slow and irregular. Magnesias and limes prepared from their respective carbonates at 1000° therefore show similar hydration characteristics.
Reactivity of lime and related oxides. X. Production of activated alkaline earth carbonates
Authors: Glasson D. R.
Published: July 2010

Samples of calcium, strontium and barium carbonates differing widely in surface activity have been prepared by calcining the oxalates, formates and acetates in vacuo and in air at a series of temperatures between 300° and 600° or 650°.

Decomposition of the organo‐metallic salts results in several‐fold increases in specific surface, especially in vacuo, as the newly‐formed carbonates recrystallise to very small individual crystals having the normal lattice structure. The products of maximum activity are obtained at or near the temperature at which decomposition is practically completed within the fixed time (5h.). The activity of the carbonate obtained from each oxalate is usually much higher than that from the corresponding formate and acetate, which require preliminary reaction between separate anions before decomposition.

The activated carbonates all sinter on further calcination, the calcium carbonate sintering more rapidly than the strontium carbonate and still more so than the barium carbonate. Hence, calcination at the higher temperatures ultimately produces barium carbonate of greater activity than strontium carbonate and calcium carbonate.

The reactivities of the carbonates in the ketonisation of acetic acid vapours are compared and discussed in relation to the temperature conditions.
An approach to applicable inorganic polymers. II. Pyrolytic and other reactions of B‐trichloro‐R‐triarylborazoles
Authors: Gerrard W. , Mooney E. F. , Pratt D. E.
Published: July 2010

The evolution of hydrogen chloride during the pyrolysis of certain B‐trichloro‐N‐triarylborazoles, (ClBNAr)3, at temperatures up to about 500°, points to the formation of boron‐carbon bonds, thereby effecting polycondensation. Formation of arylamine hydrochloride and arylaminoboron dichloride and infra‐red studies point to borazole‐ring fission, and polycondensation in a linear sense. The polymeric residue, liquid above about 300°, was a hard solid at room temperature, soluble in certain organic solvents, but was susceptible to hydrolysis. The material became solid above 500°, and was then insoluble and of considerable hydrolytic and oxidative stability.

Replacement of chlorine in the chloroborazoles by alkyl groups, hydrogen, amino and alkylamino groups is considered with reference to hydrolytic stability and future pyrolytic studies.
An X‐ray study of some reactions of chrysotile
Authors: Ball M. C. , Taylor H. F. W.
Published: July 2010

Chrysotile fibres were treated hydrothermally with aqueous suspensions or pastes of MgO, SiO2, Al2O3, Fe2O3, Ca(OH)2, Ca3SiO5 and β‐Ca2SiO4. Partial or complete reaction often occurred, but the fibres persisted as pseudomorphs which were studied by X‐ray fibre rotation photographs. Those of the products which did not contain calcium, such as Mg2SiO4, Mg3Si4O12H2 and Mg(OH)2, were usually formed with a definite crystallographic orientation relative to that of the chrysotile. A mechanism is proposed to explain this, based on the assumption that reaction occurs by migration of cations (Mg2+, Si4+, Al3+, Fe3+, H+) through a relatively unaffected oxygen framework. Products containing calcium, such as CaMgSiO4, were unoriented. This is attributed to the fact that their oxygen frameworks are more open than those of the compounds not containing calcium; because of this, their formation requires destruction and rebuilding of the crystal structure. The significance of these results for the manufacture of autoclaved asbestos cement products is briefly indicated.
Compacts of powdered material as porous bodies for use in sorption studies
Authors: Sereda P. J. , Feldman R. F.
Published: July 2010

Details are given for the production of rigid porous bodies (compacts) made by compacting under high pressure fine powders in the particle range of 10—0·01μ of silica, calcium carbonate, plaster of Paris and molecular sieves. These compacts were used as samples to study sorption and related dimensional changes. The results were used to compute spreading pressure by applying the Gibbs adsorption equation and allowed derivation of the Δl/l vs φ plots using the Bangham relation.

With compacts made from molecular sieves, it was possible to study the forces imposed on the particles by water entering or leaving the micropore system.
Studies in trans‐esterification. I. Synthesis of n‐alkyl methacrylates
Authors: Haken J. K.
Published: July 2010

The preparation of n‐alkyl methacrylates by trans‐esterification has been studied. An optimum procedure for the synthesis of n‐butyl methacrylate was developed by examining the suitability of quinol as polymerisation inhibitor and the effects of catalyst concentration and of the mole ratios of the reactants used. The mole ratio of alkanol to acid was particularly important, the optimum being much lower than that previously reported. The conclusions where they can be compared are in agreement with the results of similar work reported by Dvořkák in 1958.

By the method proposed, the reaction period and the time to recover the ester were reduced, and the yield was greatly increased. The general applicability of the method was established by the preparation of a series of n‐alkyl methacrylates.
Determination of lime stabiliser in highly ferruginous soils
Authors: Lecchini A.
Published: July 2010

Use of aqueous ammonium chloride instead of dilute hydrochloric acid for extraction of highly ferruginous soils removes insignificant amounts of sesquioxides, so that the extract can be used for determination of calcium without further treatment (as is necessary for the acid extract).
Selective liquid ion‐exchangers
Authors: Clingman A. L. , Parrish J. R.
Published: July 2010

Water‐insoluble long‐chain derivatives of various complexing agents have been prepared, and their solutions in organic solvents have been tested as selective liquid ion‐exchangers. Polymers swollen with these solutions were tried as solid ion‐exchangers in packed columns. In some cases rapid separations of metals were obtained.
Note on ‘a chromatography unit, with automatic sampling, for kinetic studies’
Authors: Spolnicki J. , Crooks W. M.
Published: July 2010

Since the publication of the previous paper1 the design of the sampling valve has been improved. It was found that the P.T.F.E. seals were ‘flowing’ into the spaces left between the shaft and the valve body, due to high temperature and constant shaft movement. This was causing a leak of the carrier gas into the sampling chamber.
Sucrose acetoacetates
Authors: Dalton L. K.
Published: July 2010

Diketen and sucrose react in dimethylformamide in the presence of triethylamine to form a mixture of sucrose acetoacetates. Excess diketen gives an almost fully substituted ester as a syrup. Sucrose esterified with three moles of diketen can be resolved into fractions containing principally the mono‐, di‐ and tri‐classes of acetoacetates. Sucrose esters of acetoacetic acid alone, or mixed esters with another acid, condense with formaldehyde to yield resins.
Quantitative study of the oxidative discoloration of ethyl linoleate. I. Oxidation in the bulk phase
Authors: Franks F. , Roberts B.
Published: July 2010

The atmospheric oxidation of ethyl linoleate has been studied in the bulk phase at 22 and 50°. The concentrations of conjugated dienes, conjugated trienes (diene ketone), and the development of a yellow coloration were obtained as functions of time from extinction coefficients measured at 234, 268/275 and 350 mμ respectively. The energy of activation of the initial hydroperoxidation reaction agrees well with previously published data. The kinetics of hydroperoxide decomposition have been studied. There appears to be a direct relationship between the rate of hydroperoxide decomposition and the rate of yellowing. The conjugated diene ketone which is formed by a second‐order hydro‐peroxide decomposition is itself oxidised, but no simple relationship can be found between the rate of oxidation and the rate of yellowing. It is therefore concluded that the diene ketone is not a colourless precursor of the yellow compounds.
Infra‐red study of hydrothermal conversion of alumina trihydrate into alumina monohydrate
Authors: Sato Taichi
Published: July 2010

Infra‐red studies have been made of the materials produced from alumina trihydrates (hydrargillite and bayerite) by heating under various conditions with water in an autoclave.
Vapour pressure and vapour density of halothane (2‐bromo‐2‐chloro‐1,1,1‐trifluoroethane)
Authors: Bottomley G. A. , Seiflow G. H. P.
Published: July 2010

The vapour pressure, in the range −50° to the normal boiling point (50‐2°), and the vapour density, in the temperature range 0–60° and at pressures up to the saturation vapour pressure, of halothane have been determined; the values are presented as equations. The vapour pressures and second virial coefficients are tabulated at temperature intervals of 10°, and gas densities at the same temperature intervals and pressure intervals of 100 mm. Hg.
‘Unexpected’ aldehydes in the oxidation products of octadecenoates
Authors: Horikx M. M.
Published: July 2010

During the autocatalytic oxidation of esters of oleic acid (9‐cis‐octadecenoic acid) and petroselinic acid (6‐cis‐octadecenoic acid) at moderate temperatures, volatile aldehydes are produced. They consist mainly of the four aldehydes predicted by the α‐methylenic free‐radical chain theory. Also significant amounts of lower ‘unexpected’ aldehydes are present; they are likewise produced during hydroperoxide decomposition in the absence of oxygen. ‘Higher’ aldehydes are virtually absent.

The conversion of methyl petroselinate hydroperoxide on a Celite/dinitrophenylhydrazine‐hydrochloric acid column yields the DNPHs of aldehydes, aldehyde esters and conjugated keto‐octadecenoates. The aldehydes are the same as the volatile aldehydes produced during autoxidation; and it is concluded therefore also the lower aldehydes are formed directly from the hydroperoxides.

The formation of lower aldehydes can be explained by assuming the presence of bishydroperoxides as minor primary oxidation products, formed in an intramolecular chain‐propagation step. An explanation is suggested for the relatively small yield of aldehydes during hydroperoxide decomposition under anaerobic conditions, in comparison with the amount formed during oxidation.
Quantitative study of the oxidative discoloration of ethyl linoleate. III. Some kinetic aspects of the early stages of the hydroperoxidation reaction
Authors: Franks F. , Gent M. , Roberts B.
Published: July 2010

The formation of conjugated diene hydroperoxide during the early stages of the autoxidation of ethyl linoleate in air and pure oxygen has been studied at 22° and 50°. The published rate equations which have been proposed for the autoxidation of olefinic systems have been integrated and the experimental results fitted to the integrated equations. In order to obtain a reasonable fit to the data, the decomposition of hydroperoxide must be taken into account. The rate constants and activation energies associated with the formation and decomposition of ethyl linoleate hydroperoxide have been obtained and are compared with previously published values.
The emission of corrosive vapours by wood. I. Survey of the acid‐release properties of certain freshly felled hardwoods and softwoods
Authors: Arni P. C. , Cochrane G. C. , Gray J. D.
Published: July 2010

The importance has been assessed of various factors responsible for the release of corrosive vapours from certain freshly‐felled hardwood and softwood species on exposure to high humidity and temperatures in excess of 30°. Variables studied include (i) season of felling, (ii) differences between sapwood and heartwood regions, (iii) initial acid content of the timber on felling, (iv) rǒle of non‐volatile extractive components in catalysing release of corrosive vapours and (v) inhibition of enzymic reactions by mild chemical sterilisation. Although the release of volatile acid is closely related to the loss of bound acetyl groups from the wood substance, indicating autohydrolysis of acetate in the cell wall material, the vapour corrosivity of a timber species is not directly related to its bound acetyl content. The presence of very small free acetic acid contents (0.01—0.03%) in some freshly‐felled undried woods is shown to play a significant rǒle in promoting rapid release of corrosive vapours by the woods (e.g., sweet chestnut and oak). Sterilisation of sweet chestnut and oak with propylene oxide vapour at ambient temperatures markedly reduces, but does not completely eliminate, release of corrosive vapours by these woods. An accompanying reduction in the proportion of bound acetate groups hydrolysed in the cell wall substance may indicate that the release of volatile acidic products from wood is in part due to a microbiological hydrolysis as well as chemical hydrolysis.
The reaction of 3 CaO,Al2O3 with water in the presence of CaSO4,2H2O
Authors: Stein H. N.
Published: July 2010

The reaction of 3CaO,Al2O3 with water in the presence of CaSO4,2H2O is investigated in suspensions and in pastes. In both, essentially the same sequence of reactions is found, the hydration products being (in the order of their appearance) ettringite, hydrous alumina, calcium aluminate hydrate monosulphate, and sulphate‐free hexagonal aluminate hydrates. In pastes, indications of water transport as an important factor in determining the reaction rate are found. Acceleration of the reaction after consumption of most of the sulphate ions present is probably due to chemical conversion of a retarding hydrate layer.
The influence of movement and temperature on the corrosion of mild steel. II. High purity water
Authors: Butler G. , Stroud E. G.
Published: July 2010

The corrosion of mild‐steel tubing by high‐purity water flowing at velocities up to 400 ft./min. and at temperatures of 25, 40 and 55° has been studied over periods of 1–10 weeks. The extent of attack was measured quantitatively from changes in weight of the tube specimens and qualitatively by visual examination and photography. The composition of the corrosion products was elucidated by X‐ray powder diffraction.

The rate of attack, k1, increased with flow velocity, v, up to a maximum at about 200 ft./min. according to an expression of the form
equation image

The rate of attack fell on further increase of flow velocity and at 300 and 400 ft./min., k1 did not differ significantly from its value at 2.4 ft./min.

The low values for the activation energies confirm that the corrosion reaction is controlled entirely by the rate of diffusion of oxygen to the metal surface at low flow velocities. At higher temperatures there are indications that both the rate of diffusion and the rate of cathodic reduction of oxygen are involved.

The amount of goethite, α‐FeOOH, in the corrosion product increased with flow velocity, which was indicative of the higher rate of oxidation of the ferrous ion initially formed. The decrease in corrosion rate at the highest flow velocities is attributed to the formation by this oxide of a more protective barrier layer.
Reduction of metal oxide fines by direct mixing with mazut. III. Application to pure stannic oxide and cassiterite
Authors: Sadek Hussein , Habashy M. G.
Published: July 2010

The reduction of pure stannic oxide by direct mixing with mazut (a petroleum product) in the presence of lime and water, is studied for various paste compositions. It is found that a paste of the oxide 68—70%, mazut 20%, lime 4—6% and water 4—6%, can be almost completely (> 94%) reduced. The extent of reduction increases slightly with decrease of particle size. Cassiterite fines were similarly reduced under conditions in which were varied (i) the starting temperature of heating; (ii) the duration of heating; (iii) the atmosphere in the reduction process; and (iv) the maximum temperature of heating. Complete reduction (94.3%) was obtained with a paste composed of cassiterite fines (< 0.2 mm. mesh size) 82%, mazut 14%, lime 2% and water 2% by thermal treatment for 5 min. in a mazut vapour atmosphere and a maximum temperature of 1000°. Complete reduction was readily obtained with any starting temperature of heating between room temperature and 900°.
Crystal nucleation from aqueous solution
Authors: Melia T. P.
Published: July 2010

The theories of crystal nucleation from solution and the experimental techniques which have been used to study this phenomenon, are reviewed. A more detailed review of nucleation from aqueous solution follows in which attention is drawn to the two types of nucleation, primary and secondary, which characterise the crystallisation of electrolytes from aqueous solution.
The effects of some organic acids and salts on the setting of gypsum plaster. II. Tartrates
Authors: Combe E. G. , Smith D. C.
Published: July 2010

In continuation of previous work on the setting of gypsum plasters,1 study has been made of the effects of tartaric acid and potassium and calcium tartrates on this reaction.

Tartaric acid (like acetic acid) has little retarding power, except in the higher concentrations. The marked accelerating effect of the potassium salt is attributed to precipitation of tartrate ions as calcium tartrate, with the formation of potassium sulphate; this is supported by several similarities between the effects of potassium tartrate and those of potassium sulphate, as determined by Smith et al.2 Calcium tartrate has negligible effect on the reaction.
An approach to applicable inorganic polymers. V. Borazine‐phosphonate systems especially those containing the vinyl group
Authors: Brown G. C. , Deuters B. E. , Gerrard W.
Published: July 2010

In the continued search for useful inorganic polymers, boron‐containing monomers having the vinyl group attached to boron and/or phosphorus were prepared. B‐trimethyl‐borazines (MeBNAr)3 (Ar = o‐ or p‐EtC6H4) were α‐brominated by N‐bromosuccinimide; but dehydrobromination to introduce the vinyl group was of limited success. Vinylboron dichloride reacted with ethyl phosphate or bis‐(2‐chloroethyl) vinylphosphonate to give the alkyl chloride (EtCl or Cl2C2H4) and polycondensates containing presumably P‐O‐B linkages. Similar results were obtained with the vinylphosphonate and B‐trichloroborazine, or B‐trichloro‐N‐tri‐o‐ethylphenylborazine or o‐ethyl‐phenylboron dichloride. Interaction of B‐trichloro‐N‐triallylborazine and tri‐n‐butyl phosphate similarly gave n‐butyl chloride and the B‐O‐P compound.

Reduction of functionality of boron and/or phosphorus by attachment of the vinyl group did not lead to a marked improvement in the properties of the condensates. Prospects of incorporating vinyl polymerisation are not promising; nevertheless further knowledge of the factors relating to P‐O‐B and similar polycondensation systems has been gathered.
Reactivity of lime and related oxides. XIII. Sulphating of hydrated lime
Authors: Glasson D. R.
Published: July 2010

Samples of quicklime and hydrated lime have been sulphated by sulphuric acid and by sodium sulphate solutions at 22°. Rates of sulphating, changes in surface area and phase composition and crystallite size have been correlated with the surface properties of the initial limes. The products have been compared with calcium sulphate dihydrate directly precipitated from solution by double decomposition, and subsequently aged.

In acid sulphating, the gypsum from the quicklime has approximately the same specific surface (and average crystallite size) as that directly precipitated from 0.5 M‐calcium nitrate and N‐sulphuric acid. The more active intermediate hydrated lime dissolves more readily and does not impede the sulphating so seriously as the less active initial hydrated lime samples. The latter give products with larger specific surface (smaller average crystallite size) from the more concentrated acid solutions, where the rapid separation of gypsum ultimately impedes the sulphating of the remaining lime.

Sulphating with 0.5 M‐soldium sulphate produces increasing alkalinity until about 16% of both the quicklime and the hydrated lime have been converted to gypsum. The sulphate initially separating, probably as a gel, impedes the reaction. The surface decreases until the gypsum begins to crystallise, but its crystallinity remains inferior to that of the acid‐sulphated lime of much lower specific surface.
Corrosion control in a water cooled stator
Authors: Wall K. H. , Davies I.
Published: July 2010

Benzotriazole (B.T.A.) is shown to be a satisfactory corrosion inhibitor for copper in closed‐circuit, water‐cooled stators. Laboratory and plant tests indicate that conductivity increase and copper pick‐up are significantly reduced at concentration levels greater than 20 p.p.m. of B.T.A.
Some analytical implications of the interaction between the water and oxygen permeabilities of polymers
Authors: Everitt G. E. , Potter E. C. , Thompson R. G.
Published: July 2010

Tubes of polythene, polypropylene, furfural polymer (‘Tygon’) or polytetrafluoroethylene are normally permeable to atmospheric oxygen when deoxygenated water flows through them. Both polypropylene and Tygon can achieve a state of impermeability after prolonged contact with water, and this is due to the steady‐state water transmission through the tube‐wall becoming sufficiently vigorous to exclude the oxygen that attempts to penetrate in the opposite direction. It is shown that the achievement of oxygen impermeability by this mechanism can depend on the cross‐sectional dimensions of the tube. Hence only the smaller of two polypropylene tubes achieved impermeability to atmospheric oxygen. On account of the special conditions required for oxygen impermeability, it is considered that none of the four types of polymer tubing tested in this work is suitable for routine use in the sampling of water before microdetermination of dissolved oxygen.
The reactions occurring during the refining of benzene with concentrated sulphuric acid. II. Removal of thiophen
Authors: Roberts D. , Gore P. H.
Published: July 2010

The reaction involved is of first‐order, but prolonged action of the acid leads to return of thiophen to the organic phase. The velocity constant is directly proportional to, but the time required for maximum extraction is independent of, the amount of acid used. The presence of olefins leads to reduced amount of thiophen removed, but maximum removal is effected in a shorter time. The system does not obey the Arrhenius equation and low temperature is desirable for the process.
Adhesion tests for bituminous materials
Authors: Mathews D. H. , Colwill D. M. , Yüge R.
Published: July 2010

A series of aggregates of known road performance with 300‐pen. bitumen in bitumen‐macadam wearing‐courses has been examined by five different, known adhesion (stripping) tests.

The results of the Static Immersion and Mallison Tests showed no satisfactory correlation with each other, with the results of other tests or with practical performance. The other three tests gave more satisfactory results which bore some relation to each other and to practical performance. The Immersion Wheel‐tracking Test gave the best general relation to practical performance provided that the effects of stability of partially stripped materials were taken into account as well as the amount of stripping. The Riedel & Weber and Immersion Compression Tests gave good correlation with road performance for mixtures not showing stripping in practice and also detected those mixtures which stripped readily on the road. With aggregates of intermediate road performance, the test results were less satisfactory. There is reason to suspect the validity of both of these tests when adhesion agents are present in the binder.
Viscosity/temperature equations for coal tar pitches and refined tars
Authors: Wood L. J. , Downer M.
Published: July 2010

The viscosities of eighteen tar products ranging from refined tar of 34° equiviscous temperature to electrode binder pitch of 102° softening point (Ring Ball) have been measured between wide temperature limits and within the viscosity range of 10 to 1010 centipoises. The applicability of three equation forms to these results has been assessed. A simple logarithmic relationship in terms of Fahrenheit temperature is satisfactory for most products at viscosities greater than 104 centipoises, but does not apply at lower viscosities or to the harder pitches. A double logarithmic viscosity/temperature relationship fits the results well, except those relating to the hard pitches, but it is insensitive and unreliable at viscosities of about 109 centipoises and greater. A third equation relating the logarithm of viscosity to the fifth power of absolute temperature has been shown to apply over the full range of materials, temperatures and viscosities examined.

The significance of the constants used in these equations is discussed with respect to their value in comparing the temperature susceptibility of tar products.

It is shown that the correct order of viscosity of a tar product, within the range of materials and viscosities investigated, can be predicted from its softening point or equiviscous temperature and its toluene‐insoluble content.
Reactivity of lime and related oxides. XV. Crystalline forms of sulphated lime
Authors: Glasson D. R.
Published: July 2010

Changes in surface area and crystallite size in the interconversions of the forms of sulphated lime have been related to time and temperature conditions.

The specific surface increases when hemihydrate, ‘soluble’‐γ‐ and ‘anhydrite’‐β‐calcium sulphate are formed during the thermal decomposition of gypsum. The activation is initially delayed in each dehydration stage, before the products recrystallise to their normal lattice structures. Subsequently, the specific surface decreases (and the average crystallite size increases) as each product sinters.

‘Wet’ rehydration of γ‐calcium sulphate rapidly replaces the water in the zeolitic hemihydrate structure, without appreciably ageing it. The less mobile ‘dry’ rehydration in water vapour produces hemihydrate extensively aged. Both ‘wet’ and ‘dry’ conversions of hemihydrate to gypsum are completed with considerable loss of surface. The gypsum crystallinity is more rapidly developed during the ‘wet’ rehydration. Effects of additives on the rehydration and ageing of hemihydrate gypsum plasters have been similarly studied.

Anhydrite ‘dry’ rehydrates only very slowly, but ages considerably. ‘Wet’ rehydration slowly produces gypsum of low crystallinity; the surface initially increases, before decreasing greatly as the rehydration accelerates. The rehydration rate finally falls as the material continues to age and improve in gypsum crystallinity.
Hydrous oxides and their cation‐exchange properties
Authors: Heitner‐Wirguin C. , Albu‐Yaron A.
Published: July 2010

The hydrous oxides of thorium and titanium were prepared and their cation‐exchange properties studied. The hydrous oxide of titanium has good physical and chemical stability and shows good exchange capacities within wide ranges of pH and temperature. The kinetics of the cation‐exchange reaction were studied and the diffusion coefficients and energy of activation calculated.
Preparation of 2‐methylanthracene by continuous catalytic condensation of 2,5‐dimethylbenzophenone
Authors: King L. F.
Published: July 2010

2‐Methylanthracene can be synthesised by batchwise cyclodehydration of 2,5‐dimethylbenzophenone by the Elbs reaction in about 15% of the theoretical yield, but this can be raised to 63% by use of an activated carbon catalyst in a continuous process with benzene as solvent.
Reactions on titanium dioxide: The photo‐oxidation of ammonia
Authors: McLean W. R. , Ritchie M.
Published: July 2010

The adsorption at room temperature of small amounts of ammonia on precipitated titanium dioxide was accompanied by the release of water in unit molecular ratio. When titanium dioxide films were illuminated with light of wavelength 3650–4350 Å in the presence of ammonia and oxygen, photo‐oxidation of ammonia occurred, in which the oxygen used appeared mainly as water; small amounts only of nitrous oxide and of nitrite were found. Three molecules of ammonia reacted with two molecules of oxygen to give four molecules of water. Consideration of the amounts of oxygen separately photosorbed, of ammonia thermally adsorbed and photo‐oxidised, and of nitric oxide photo‐decomposed, leads to the conclusion that common reaction sites on the dioxide surface are concerned. These reactions and the photodecomposition of nitric oxide on an ammonia‐treated surface. are interpreted in terms of Lewis‐type reaction centres, involving water or ammonia.
Thermal decomposition of a blackband ironstone. I. Overall mass and energy balances
Authors: Gardiner S. P. , Long V. D.
Published: July 2010

A sample of blackband ironstone containing 31% iron and approx. 26% sapropelic coal was calcined in a small fixed‐bed under reducing conditions to give a solid residue, aqueous and tarry distillates and an inflammable gas. By observing weight‐loss and gas composition as a function of temperature, reaction was found to occur in two stages, the first (200–600°) involving decomposition of ferrous carbonate and coal, and the second (700–900°) further pyrolysis of the organic residue. From analyses and heats of combustion of the products, mass and energy balances have been set up, and an estimate of the heat of decomposition obtained.
Extraction of tar acids from low‐temperature tar oils by acetic acid
Authors: Nair C. S. B. , Sen D. K. , Basu A. N.
Published: July 2010

Aqueous acetic acid has been found to be a good solvent for the extraction of tar acids from low‐temperature tar oils. Acetic acid 60% (w/w) at 25° in the solvent/feed ratio of 1 : 0.8 effects a recovery of more than 89% of the tar acids present in the tar oils in two extraction stages. Besides tar acids, the acetic acid also extracts tar bases and neutral oils present in the oil to some extent. Re‐extraction with light petroleum reduces the neutral oil carry‐over by about 50%.

The phase‐equilibrium characteristics of the system tar acids‐(bases + neutral oils)‐60% aqueous acetic acid have been studied. It is seen that two theoretical extraction stages could effect the recovery of 96% of tar acids from a feed oil containing 45% of tar acids. Use of light petroleum could reduce the neutral oil contamination of the extract by 76.2%. The tar acids could be recovered from the extracts by distillation.
Chemical aspects of the production of television tube screens. II. The formation of the screen
Authors: Lines F.
Published: July 2010

In the manufacture of screens, the ‘wet adhesion’ of the screen has to withstand the pouring off of the settling liquid. Measurement with a liquid jet gave wet adhesion constants for the various types of screen, and by this means the factors controlling wet adhesion have been studied.

Particle size of the phosphor powder and its surface area and charge determined whether a screen could form at all. The development of adhesion depended upon the rate of reaction between potassium silicate and barium nitrate (see Part I). At low reaction rates, no direct comparison between adhesion and flocculation was possible, but at higher reaction rates, the adhesion constant decreased as rate increased because reaction took place in solution rather than between particles in the screen.

Using co‐ordinates of solution concentrations, lines of equal wet adhesion could be drawn, giving areas of adhesion higher than a given value in a given time. This provides an area of acceptable screen quality in production. Factors which increase flocculation tendency also decrease the size of this area, and so make settling a more critical process.
The preparation of isopropyl silicate from chloro‐silanes obtained by reacting silicon with hydrogen chloride
Authors: Emblem H. G. , Hargreaves K.
Published: July 2010

The object of this investigation was to find out if the hydrogen chloride by‐product formed in the preparation of isopropyl silicate from tetrachlorosilane might be recovered by reaction with silicon to give a chlorosilane mixture from which an isopropyl silicate having a silica content of about 40% could be prepared. The reaction between hydrogen chloride and silicon in the presence of a copper catalyst was, therefore, studied. The effect of flow rate of hydrogen chloride gas, particle size of the silicon, concentration of catalyst, and reaction temperature, on the yield and product of the reaction have been investigated. The reaction product is a mixture of tri‐ and tetra‐chlorosilane in various proportions, with a trace of dichlorosilane. Isopropyl silicate having a silica content of about 40%, and free of silane hydrogen, has been prepared in good yield from this reaction product and a mixture of water and isopropyl alcohol.
Adsorption in urine conversion
Authors: Quon J. E. , Grieves R. B.
Published: July 2010

The need for a selective method for the removal of urea from urine is enhanced by the success of electrodialysis for removing electrolytes from urine. An investigation has been made of the capacities of an activated charcoal and an ion‐exchange resin (Amberlite IR‐120) for removal of urea from aqueous solution and from urine. In the charcoal column studies, determinations were made of the service time, the shape and thickness of the wavefront, and adsorbent capacity.

The values of the adsorbent capacity of 6–14 and 50–200 mesh activated carbon are approximately 0.027 g. of urea/cm.3 gross volume of carbon. For column lengths of the order of the thickness of the wavefront, approximately 0.6 of the capacity is used before the effluent urea concentration reaches 5% of the influent concentration. On the average, one chloride ion is removed from urine for each 1.3 molecules of urea adsorbed. The capacity of the activated carbon in removing urea from aqueous solution is approximately 10% greater than that for removal of urea from urine. The capacities of Amberlite IR‐120 ion‐exchange resin are 0.023 and 0.090 g. of urea/cm.3 gross volume of resin for removal of urea from urine and from aqueous solution, respectively.
Chemical methods for the dating of fossils
Authors: Glover M. J. , Phillips G. F.
Published: July 2010

The relative dating of palaeontological specimens may be assisted by an analysis for selected elements: methods for the determination of fluorine, phosphate, iron and carbonate are described and assessed. Some examples of the application of such analyses are discussed.
The ionic concentration in the suspending liquid during the hydration of a slurry
Authors: Schiller K.
Published: July 2010

On the basis of a previously proposed mechanism to explain hydration of plaster, the changes of concentration in the liquid medium are calculated. Separate evidence based on conductivity measurements and radio‐tracer methods are given.