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The preparation of 4-amino-1,2-ethylenedioxybenzene by cathodic reduction of the corresponding 4-mononitro compound is described. The amino compound obtained is easily diazotized and, on coupling with different azo components, new azo dyes of, in general, good quality and brilliant colour are derived.

In this paper the dyeing process of silk with an acid dye is explained by means of density measurements. The adsorption of hydrogen by silk has been measured and found to be in correspondence with the explanation of the dyeing process. From the sorption measurements in air, it can be deduced that the sorption of air by silk is principally a chemo-sorption. From the density of silk in helium the number of possibilities found in the literature for the lattice of Bombyx-Mori silk can be reduced to a single one. By comparing degummed and raw silk, it was found that the sericins are low molecular proteins, which sorb neither hydrogen nor air. The relation is discussed between chain-length, relative positions of the chains, on the one hand, and the sorption properties, density etc. on the other hand. The densities of silk cited in the literature are criticised and compared with the author's observations.

In this paper the relations between the volumes of dry fibres and fibres with different percentages of regain are discussed. With the aid of these relations and based on the opinion, that a solid substance will not sorb a liquid with appreciable contraction, the conclusion is reached that water will be sorbed by hydrophylic fibres in three ways, viz.: 1 by absorption in the outer layer of the micelles, 2 by adsorption at the micelle surface without contraction, and 3 by capillary condensation also without contraction. The effect of the felting process and dyeing processes on the quantity of water sorbed, and more generally on the sorptive capacities of the fibres cotton, silk and wool is discussed.

Proceeding from the Keuffel & Esser Color Analyzer a photo-electric apparatus was designed, which can render good service for the colour measurement of dyed textiles. The reflection at one or more wave lengths is determined and taken as a colour coordinate when studying the relation between the quantity of dyestuff on the fibre and the resulting colour.

The nitrating potentialities of mixed acids consisting of HNO3 and SO3 as compared with mixed acids of HNO3 and H2SO4 have been investigated on three examples, viz the easy nitration of p-chloronitrobenzene to chloro-2:4-dinitrobenzene, the difficult nitration of this compound to chloro-2:4:6-nitrobenzene and the relatively easy nitration of 2:4-dinitrotoluene to 2:4:6-trinitrotoluene in which oxidation can be rather marked. The experiments have been carried out batch-wise and continuously. From the experiments it could be concluded that the HNO3-SO3 acids with an SO3 content between 40 and 72% SO3 are good nitrating acids. For difficult nitration the use of acid with ∼70% SO3 shows a definite advantage over acids of HNO3 and H2SO4. For the acids containing ∼45% of SO3, which in view of their thermal stability can only be used for relatively easy nitrations, the difference between the two types of acids is not very large. However, the advantage of the better SO3-economy with the HNO3-SO3 acids is always present.

Some derivatives of naphthodioxan, 5-amino-naphthodioxan, and of naphthodioxan-7-sulphonic acid, including azo dyes, mostly substituted in the 5- and 10-positions, are described in this paper.

Some physico-chemical properties of the system HNO3-SO3 are described. From the melting point curve the existence of some crystalline compounds could be derived. The very stable compound HNO3. 2SO3 was isolated (m.p. 112° C), a compound - possibly 2HNO. 3SO3 - was found (m.p. 106° C), and a compound HNO3. 3SO3 could be isolated (m.p. 41° C). Liquid HNO3 and SO3 are not completely miscible. Between 90% SO3 and nearly 100% SO3 there exists a miscibility gap. The vapour pressure diagram of the system HNO3-SO3 was also determined. The minimum in this diagram corresponds to HNO3. 2SO3. The vapour of mixtures on the HNO3 side of this minimum contains HNO3 and N2O5. On the SO3 side of the minimum of vapour contains SO3. It is posible to absorb most of SO3 from contact gas in mixtures with 80-82% of SO3 at 25° C. In molten HNO3. 2SO3 at 110° C the absorption of contact gas proceeds with a yield of over 90%.

In this paper a study is given about the initial stages of filtration at constant pressure from which conclusions could be drawn about the interrelation between cloth and cake. It was found that - with one system - two types of filtration may occur, blocking filtration and cake filtration, depending on the concentration of the solid substance in the prefilt: By increasing this concentration blocking gradually decreases and finally blocking filtration changes to cake filtration. With cake filtration at constant pressure the specific resistance of the cake depends on the concentration in the prefilt; decreasing with increasing concentration. An equation for complete blocking filtration has been derived.

The behaviour of the calcium-aluminium-alizarate complex on alumina is described. By elution with mixtures of dimethylformamide and water two fractions can be isolated. It has been shown that these fractions are not cis-trans isomers. In all probability the two fractions differ in the charge distribution of the electrons, caused by a difference in water content.

A combustion method for accurate isobutanol determination in dilute aqeous solutions, to be used for serial determinations, is given.

A quantitative description has been presented of anaerobic treatment in an upflow reactor of dilute waste water containing lower fatty acids as the main pollutant. It contains as its principal elements mathematical descriptions of the dynamic behavior and the distribution of both the fluid and the anaerobic sludge in the reactor, and a quantification of the kinetics of the anaerobic conversion of the organic waste and of the formation of bacterial products and methane. These elements have been taken together in mass (organic carbon) balances for the substrate, the methane, and the bacterial products, over the two most important reactor parts: the sludge bed and the sludge blanket. In the second part of this article, the description has been used for prediction and determination of the optimum reactor dimensions and process conditions. These optimum values can be used for the design of new reactors and for the establishment of the best suited process operation, which is important for obtaining the best purification results and process reliability at minimum investment and operation costs. (Refs. 13).

By means of stimulus-response experiments with a Li+ tracer, a description of the fluid flow in a 30 m3 reactor, used for anaerobic treatment of wastewater, was derived. It appeared that of the three parts that could be distinguished in the reactor (the sludge bed. The sludge blanket, and the settler), the sludge bed could be described as a combination of two perfectly mixed regions with bypassing and return flows; the sludge blanket was perfectly mixed, while the fluid flow in the settler could be described as plug flow. From experiments performed under different conditions it was concluded that 60 m3 gas/day were sufficient to provide good mixing and also that the height of the sludge bed should be 2–3 m. From this last conclusion it follows, e.g., that scale-up of the 30 m3 reactor should be done by increasing the cross section of the reactor while homogeneously distributing the influent over the bottom.

We had reason to doubt the correctness of current opinion that the formula of the calcium–aluminium lake of alizarin (Turkey Red) is Ca2A13Az4 (where Az represents an alizarin molecule minus two hydroxylic hydrogen atoms). We therefore carried out a further study of this complex, the results of which are presented in this paper. The molecular structure of the complex has been established. The complex has been prepared in vitro and purified by washing, crystallisation, and chromatographic separation. The structure has been elucidated by conventional analytical methods, including infrared spectroscopy. The basic compound has been established to be CaAl(OH)(Az)z, in which calcium is bound as an ion and aluminium forms part of a chelate ring with the 9-carboxyl and 1-hydroxyl groups of alizarin. This compound can take up three molecules of water, forming a new compound in which the water molecules are part of the molecular lattice. This new compound can form a hydrate with another three molecules of water.

The photoreduction of eighteen different monoazo dyes in aqueous and ethanolic solutions, containing d, l-mandelic acid or acetone as hydrogen donors, to the corresponding amines has been investigated by flash-photolysis and rapid-flow techniques. The photoreduction of azo dyes proceeds in stages involving hydrazyl radicals and hydrazo compounds. The former are formed in a rapid reaction of the azo dyes with the active reducing agent produced upon absorption of light by the hydrogen donor. These radicals are unstable and disproportionate with formation of hydrazo compounds and regeneration of the original azo dye. The hydrazo compounds are also unstable and decompose with formation of amines and regeneration of the dye. The reaction schemes presented are supported by kinetic evidence and electron spin resonance measurements.

Azo dyes are photoreduced rapidly when solutions in water also containing dl–mandelic acid are exposed to ultraviolet radiation. Since the active reducing species in this reaction is formed from the photoexcited mandelic acid, the wavelength region responsible for the fading coincides with the region in which mandelic acid absorbs. The photoreduction reaction can be sensitised to longer wavelengths by the addition of sodium–9, 10–anthraquinone–2–sulphonate. The mechanism of sensitisation has been investigated and it has been found that semiquinone radicals are formed by hydrogen abstraction from dl–mandelic acid by the photoexcited anthraquinone derivative. The semiquinone radicals can reduce the azo dyes to the corresponding amines, the quantum efficiency of this reaction being almost unity.

The reaction of hydrogen atoms, prepared according to Langmuir by passing a stream of hydrogen over a glowing tungsten wire, with liquid hexadecene-1, hexadecane and linseed oil is described. With hexadecane saturated higher molecular hydrocarbons are formed. With hexadecene hydrogenation as well as polymerization occurs, the polymerization products being partly unsaturated. With linseed oil conjugation of the double bonds occurs besides hydrogenation and polymerization, but only to a small extent. Interaction of H-atoms with the double bond proceeds faster than with the saturated part of the molecule, though the last reaction definitely makes a contribution to the overall reaction. Formation of unsaturated products from the corresponding saturates hardly occurs. Other literature is reviewed in connection with the present work.

Various methods of polymerising ethylene are described in the literature. Ethylene as such or in a liquid medium is polymerised with an aluminum chloride catalyst; the yield of lubricating oil fractions obtained by these known methods is relatively low, further they have a low viscosity index (Dean and Davis). The high molecular fractions are rather strongly unsaturated and cyclic. The authors have discovered a new method of polymerising ethylene or gases containing ethylene characterised by a high pressure polymerisation, working with a liquid diluent and using aluminum chloride as a catalyst combined with the action of nickel or nickel alloys. The temperature at which this process is carried out lies below 100° C; 70 to 80% of the reaction product consists of lubricating oil fractions, which have a viscosity index of 70 to 100. The velocity of the process is high, while the temperature at which it is carried out, is low.

Dans cette publication sont donnes les spectres d'absorption de quelques derives benzeniques amines et le comportement spectrographique de ces derives dans des solutions aqueuses acides. Ce travail fait partie d'une recherche sur le role joue par l'azote lors de son introduction dans les derives benzeniques. En outre, on trouvera dans cette publication une premiere etude des changements de constitution qui ont lieu lors de la formation des colorants du triphenylmethane par l'addition d'acide a une base carbinol.

The molecular structures of some complexes of alizarin have been established. It has been shown that all these compounds have the sane general type of structure and that they consist of a complex anion (a chelate of alizarin with a trivalent metal) with a uni-, bi- or quadri-valent metal cation. Before complex formation, salt formation of the alizarin molecule is necessary, because otherwise complex formation will be very slow.

By means of the determination of the true densities in helium and the apparent densities in air, hydrogen, benzene and water of some samples of wool, the dyeing process of wool with acid and basic dyes and the felting process of wool are studied, and some conclusions with regard to these processes are drawn. Moreover the sorptive capacities of wool for air and hydrogen are calculated, and the nature of these sorption phenomena is discussed.

Irradiation of dl-mandelic, phenylacetic, formic, malonic or dl-tartaric acid in aqueous or ethanolic solutions with U. V. light results in the photodecomposition of these acids into ·COOH and the respective residual radicals. The ·COOH radical has strong reducing properties and can reduce azo dyes, if they are added to the solution prior to irradiation, to amines. The residual radicals formed together with ·COOH upon photodecomposition of the carboxylic acids, can cause fading of the dyes either by reduction or by addition to the chromophoric system.

In this paper an improved method for the preparation of 6-nitro-1,4-benzodioxane, the preparation of 6-amino-7-nitro-1,4-benzodioxane and of 6-amino-1,4-benzodioxane-sulphonic acid is described. Some azo dyes derived from the last two substances, showing moderate to good properties, are given.

The activity of atomic hydrogen as a polymerization agent for unsaturated organic compounds has been investigated. Two methods were used to prepare pure atomic hydrogen. The first was a modified Langmuir method, passing hydrogen over a glowing tungsten wire, and removing the hydrogen ions formed. The second was Cario and Frank's method, by which atomic hydrogen is prepared by means of ultraviolet light. It could be shown that atomic hydrogen causes polymerization as well as hydrogenation of unsaturated organic compounds.

For mercerised cotton, undyed and dyed with a substantive dye, the true densities in helium and the apparent densities in benzene, water, air and hydrogen are given in this paper. The conclusion is reached that in cotton dyed with a substantive dye, the dye is bound intermicellarly, without changing the cotton substance. Hydrogen as well as air are adsorbed by cotton; the quantities adsorbed are not altered by the dyeing process. The opinion of Campbell and Russell that the true density of cotton will be found in water and not in helium, is disputed. Some remarks are made on the dyeing processes of cotton, silk and wool with direct dyes.

The decomposition at high temperatures over glass-wool of the acetic acid esters of butanol-1, butanol-2, 2-methylpropanol-1, 2-methylpropanol-2, 2-methylbutanol-1, 3-methylbutanol-1 and hexadecanol-1 to acetic acid and the corresponding alkene was investigated. It was found that glass-wool is not the active catalyst for the reaction. In some cases a small amount of isomerism of the double bond could be detected. Some observations on the reaction mechanism are included.

The conversion of picryl chloride into phloroglucinol has been studied by a combination of methods for the same or similar substances already presented in the literature. The reduction of picryl chloride to 1,3,5-triaminobenzene with tin in hydrochloric acid could be reproduced quite well and gave, in combination with the well known hydrolysis of the triamino-compound, a possible method. Contrary to the literature the reduction of picryl chloride with iron (Bechamp's method or excess of hydrochloric acid) was not satisfactory. A rather elegant method has been found based on the electrolytical reduction of picryl chloride followed by immediate conversion of the 2,4,6-triamino-1-chlorobenzene hydrochloride, so formed, as dissolved in the catholyte, to phloroglucinol, by heating in a slightly alkaline solution containing stannous chloride and hydroxide at temperatures of 140-160° C.

The determination of the partial coefficients of heat and mass transfer in air from and to a drying fluidized mass of silica gel is given. The analogy between the two methods of transport in the bed has been studied by an inspection of the relation between the two coefficients. A correlation of these coefficients with the void fraction, the superficial velocity, the particle size and the tube diameter of the bed has been derived. This correlation has been transformed into a correlation of dimensionless groups. On determine les coefficients partiels de transfert de chaleur et de transfert de masse entre l'air et une masse fluidifiee de gel de silice, pour des echanges dans les deux sens. Les auteurs etudient l'analogie entre les modes de transfert dans le lit par inspection de la relation entre les deux coefficients. On a deduit une correlation entre ces coefficients et la porosite, la vitesse superficielle, les dimensions des particules et le diametre du tube. On a transforme cette correlation et une expression a groupes sans dimensions.

It has often been assumed that the oil used in the traditional Turkey Red dyeing processes is an essential constituent of the dye complex formed on the cotton fibre. Work is now described which shows that the same complex is formed in vitro and on cotton fabrics mordanted with aluminium salts in the presence of calcium ions, both in absence and in presence of oils, e. g. Turkey Red oil; the formula of the complex is CaAl(OH)(Az)2. Factors governing the deposition of the complex within the cotton fabric are discussed. For level dyeing, fixation of the mordant should take place at pH 8, which is also the optimum dyebath pH; in the dyeing process itself, alizarin should be present in excess of the amount necessary for complex formation.

Solutions of azo dyes iii water containing different soluble substrates have been exposed to ultraviolet and visible radiation. It has been found that many compounds react photochemically as hydrogen donors and cause reduction of azo dyes present in the same solution. Fading of such solutions takes place only when the radiation is absorbed by the substrate. Fading is evidently the result of interaction of excited substrate molecules with dye molecules or excited dye molecules. Substrates containing carboxyl, hydroxyl, or aryl groups attached to methyl, methylene, or aliphatic CH- groups show high photochemical activity when the compounds absorb light of long wavelength. Kinetic measurements have shown that the fading reactions are of first order with respect to the concentration of the excited substrate molecules at low substrate concentrations. Fading of azo dyes in solutions containing different substrates is partly inhibited by the presence of oxygen. The results indicate that oxygen can act as a hydrogen acceptor in the same way as the azo dyes. Kinetic experiments carried out for one system suggest that the inhibition is partly caused by reoxidation of reduced dye radicals to the original dye by peroxide radicals. A mechanism for the inhibition is proposed.

The preparation of the potassium and calcium salts of alizarin and of 3-nitroalizarin is described. Their structures have been established and compared with those of salts of complex alizarates containing the same metals, which have been described in the preceding parts of this series. It was already known that, prior to complex formation, salt formation must take place. With the knowledge of the structure of these salts, the mechanism of complex formation following salt formation has been established. An intermediate monobasic salt, e.g. potassium 2-alizarate or the acid calcium 2-alizarate, is formed, from which the complexes are produced with the chelating metal ion. During dyeing with Turkey Red (calcium-aluminium lake of alizarin), calcium alizarate is not formed, because the intermediate acid calcium salt reacts more quickly with aluminium hydroxide to form the complex than the calcium atom in the acid salt reacts with the 1-OH group.

The preparation and orientation of naphthodioxan (2,3-naphtho-p-dioxan (2,3-dihydro-naphtho-[2,3]-p-dioxin)), 5-, 6-, and 7-mononitro-naphthodioxan, 5-, 6-, 7-monoacetylamino-naphthodioxan, as well as 5-, 6-, and 7-naphthodioxan monosulphonic acid and some derivatives, are described in this paper.

A cryoscopic study of mixtures of HNO3 and BF3 reveals the existence of a compound HNO3. 2BF3 (melting point 53° C). Mixtures of composition HNO3. 1/2BF3, HNO3. BF3, HNO3. 2BF3 and HNO3. 1/2SO3 were studied spectroscopically. In liquid HNO3. 1/2BF3 and HNO3. BF3 the reaction HNO3 + BF3 NO+2 + BF3OH- takes place to a more or less considerable extent. In HNO3. 2BF3 no clear indication for the presence of NO2+ ions is found. HNO3. 2BF3 probably is an addition compound comparable with those described by Baumgarten c.s. for BF3 with a number of sulphates or pyrophosphates. In liquid HNO3. 1/2SO3 a considerable amount of NO2+ and HSO4 ions are present.

The molecular structure of some metal complexes of 3-nitroalizarin, 3-aminoalizarin, and sodium 3-alizarinsulphonate has been established. It has been found that all these compounds have the same basic structure as that of the corresponding complexes of alizarin, as discussed in Part II of this series.

Zwei Kriterien werden fur den Ubergang von homogener zu heterogener Fluidisation diskutiert. Nach dem dynamischen Schallwellenkriterium entsteht eine dynamische Schallwelle, wenn die Geschwindigkeit der Kontinuitatswelle, d. h. die Geschwindigkeit mit der eine Porositatsstorung aufsteigt, groser ist als die Geschwindigkeit der dynamischen Welle. Nach dem Vibrationskriterium kann eine Wirbelschicht nur dann homogen oszillieren, wenn ϱs » ϱf, und wenn die Schichthohe L kleiner ist als eine gewisse kritische Betthohe Lc. Blasenbildung kann weiterhin nur auftreten, wenn Lc groser ist als eine Grose Lb, die von der Amplitude der Oszillation bestimmt wird. Das Vibrationskriterium lautet also Lc > Lb. Blasen treten dann auf, wenn L > Lc ist.

Irradiation of dl-mandelic, phenylacetic, formic, malonic or dl-tartaric acid in aqueous or ethanolic solutions with U. V. light results in the photodecomposition of these acids into ·COOH and the respective residual radicals. The ·COOH radical has strong reducing properties and can reduce azo dyes, if they are added to the solution prior to irradiation, to amines. The residual radicals formed together with ·COOH upon photodecomposition of the carboxylic acids, can cause fading of the dyes either by reduction or by addition to the chromophoric system.

Residence-time-distribution experiments for the fluid in a 30-m cubed pilot plant and a 200-m cubed prototype upflow reactor were performed by means of continuous injection of an LiCl solution as a tracer in the influent of the reactor and measurement of the response of this stimulus on several locations in the reactor and in the effluent. In a similar way as described in an article published earlier, models have been developed by use of the measured data of the fluid flow pattern which consisted of regions of ideal mixing, plug flow, dead space, and short circuiting. It appeared that the fluid flow patterns in the two reactors were to a large extent analogous. For the pilot plant, three-mixer models appeared to be appropriate while for the prototype reactor two-mixer models have been found. This difference was a result of the difference in the heights of the sludge beds in the reactor: 2-3 m in the pilot plant and only 0.4 m in the prototype reactor, a result of too small an amount of sludge. Another difference was that, due to a large amount of mud in the prototype reactor, a region of dead space occurred in the models for themore » fluid flow pattern in this reactor. The dimensions of the prototype reactor have been chosen according to several recommendations obtained from work with the pilot plant, (e.g., scale-up should be done by increasing the cross section of the reactor; one influent point should be applied per 5 m squared bottom surface). The results presented here clearly show the value of these recommendations. (Refs. 7).« less

USUALLY the porespace in a porous medium is visualised as a more or less complicated assembly of isolated or interconnected capillaries, and such porespace models are used in describing transport phenomena in porous media. If capillary rise of a (wetting) liquid in a homogeneous irregular packing of rotund particles is considered, however, it seems that none of the existing porespace models is capable of explaining, not even qualitatively, the observed phenomena1.