Erdöl-Emulsionen — Eigenschaften,Stabilität und Spaltung

Petroleum emulsions — Properties, stability, and demulsification . Petroleum always occurs together with brine and is often recovered as an water-in-oil emulsion. Emulsions containing more than 90 percent of water are known; they are often very stable. The viscosity of the emulsions rises at a faster rate than the water content and is always significantly higher than that calculated according to the Einstein equation. Petroleum emulsions are stabilized by adsorption of the asphaltenes and petroleum resins colloidally dispersed in the petroleum. These components form mechanically stable films at the water/oil interface. The films contain several anionic, cationic, and amphoteric interfacially active substances, which are associated to form micelles, and which are adsorbed at the oil/water interface as a result of their interfacial activity. The adsorption films are wetted by the oil phase. The emulsions are stable towards coalescence, but not towards flocculation. Demulsifying agents displace the stabilizers from the interface or change their wettability.     

Herstellung und Reaktionen von Bis-methoxyvinyl-ketonen

Synthesis and Reactions of Bis-(methoxy vinyl) ketones Bis-(methoxy vinyl carbonyl)alcane (10) are obtained by reaction of the instable bis(chloro vinyl)alcanes (9) with methanol. The products of the reaction of 10 with diamines are linear and soluble polyamides of the type of vinylen homologous polyamides 66. In the reaction of 10 with triamines insoluble polyamides are formed. These polymers are degradable by acids.     

Herstellung und Eigenschaften rheopexer Dispersionen

The report concerns a special kind of anomalous flow of latices being familiar to rheopexy. The rheological properties are characterized by a sudden increase in viscosity of 2 to 3 orders of magnitude within a narrow range of shear rate. The viscosity then decreases again with increasing shear rate with a gradient of —1, corresponding to a maximum shear stress of appx. 0.1 kp · cm^?2. The increase of viscosity and the shear rate at which this increase occurs, depend on the concentration and the temperature of the polymer dispersion. The rheopexy is due to the presence of groups at the surface of the latex particles being able to form hydrogen bonds. At a definite shear rate these groups interact to give a network structure of the latex particles. The network could be demonstrated by electron microscopy.     

Grundlagenuntersuchungen zur Herstellung von Emulsionen im Ultraschallfeld — Teil 2

The formation of emulsions by use of ultrasonication was investigated, particularly for low‐viscosity oils. The influence of the irradiated volume, power density, viscosity of the dispersed and continuous phases as well as the influence of the oil fraction on drop size were investigated. An equation based on turbulence theory can be used to predict the dependence of drop size on different process conditions and substance properties. Comparison with other methods shows that emulsification can be achieved with ultrasound just as efficiently.     

Wasserlösliche disulfonierte aromatische Ketone — Photophsikalische und photochemische Eigenschaften

Water Soluble Disulphonated Aromatic Ketones — Photophysical and Photochemical Properties By the sulphonation of benzophenone, xanthone, thioxanthone, acridone, and methylacridone the disulphonated derivatives BPS, XS, TXS, AcS and MAcS are produced. Their disodium salts are well soluble in water. The absorption and the emission spectral data of these ketones are similar to those of the respective parent compounds. The S₁ state of BPS alone is of n — π* type, in all the other cases it possesses mainly π — π* character. The S₁ states can serve as donors in electron transfer reactions with iodonium salts. The kinetic curves of flash photolysis of these ketones in water show two decay processes, which are attributed to the triplet state and the long living ketyl radical. The triplet absorption spectra of the disulphonated ketones are very close to those of the unsubstituted ketones, but the life times of the former are much higher. The T₁ are quenched through onium salts by electron transfer reactions. Acryl amide, too, acts as a quencher for the triplets.     

Herstellung und Eigenschaften von niedermolekularen epoxydierten aromatischen Polyäthern

The synthesis of low molecular weight epoxidated aromatic polyethers from oligomers with phenolates of alkali metals as terminal groups with epichlorohydrin in anhydrous aprotonic, polar solvents is presented. The oligomers having ? ONa or ? OK terminal groups have been synthesized by condensation of alkali metal salts of bisphenols with chlorobisphenyl compounds containing bivalent electronacceptor groups between the aromatic rings. The molar ratio of chlorobisphenyl compounds to bisphenol was in the range of 0,5:1 to 0,9:1. The dependence of reactivity of the above mentioned epoxidated oligomers in the curing reaction with diaminodiphenylsulfone (DDS) on the molecular weight and type of bisphenol has been investigated. Thermal and thermomechanical properties of these resins have been determined. The degradation temperature of the uncured resin (mw 800) obtained on the base of polysulfone oligomer was 325°C (1,5 wt.-% weight loss). The resin cured by means of DDS had a glass transition temperature of 160°C, and a tensile strength of 160–190 kg/cm², measured as adhesive between aluminium plates.     

Eigenschaften von maltodextrinbasierten Klebesystemen zur Herstellung nicht süßer Snackriegel

Two maltodextrin based adhesive agents – a paste and a film – for bonding of components in non‐sweet snack bars have been developed. Their adhesive capability, adsorption characteristics and impact on the texture of a snack produced with these agents were investigated. Despite different maximal adhesive strength, both adhesive agents exhibited a sufficient qualitative adhesive capability. The film had less impact on the texture which is attributed to its better water binding capability.     

Reaktionen von Bis-enaminen mit Aldehyden — Neue Synthesen für 1,3-Oxazine und Pyridine

Reactions of Bis-enamines with Aldehydes - New Synthesis of 1,3-Oxazines and Pyridines In the presence of phosphoric acid N-alkyl-dipropenylamines react with aliphatic aldehydes to form substituted 1,3-oxazines. With benzaldehyde this reaction does not proceed, but azomethines are formed. N,N-dipropenylaniline with aldehydes also gives azomethines, a dihydropyridine is formed as well. From tripropenylamine and aldehydes substituted pyridines are obtained.     

Liposomen – Strukturen und Herstellung

The general public has only recently become familiar with liposomes through their use in cosmetics although a wide range of applications has long been known in the scientific literature. Depending upon the pertinent application very different liposomes are required, which has led to a large number of methods for their production. This article describes the principal processes: rotor/stator dispersion, the injection method, dialysis, extrusion, and homogenisation. The most suitable methods for industrial use are rotor/stator emulsification, the injection method, extrusion, and homogenisation. Examination of commercially available liposome-containing products shows that high-value products such as cosmetics and pharmaceuticals predominate – commercial use of liposomes is often limited by the sophisticated production methods and expensive raw materials.     

Fettpolymere – Herstellverfahren und Eigenschaften

The radical polymerization of esters of acrylic, methacrylic or crotonic acid with fatty alcohols proved to be an efficient method for production of polymers with hydrophobic moieties. By co-polymerisation with hydrophilic co-monomers - such as maleic anhydride - copolymers with a broad spectrum of properties can be designed. As an example the copolymerisation of fatty crotonates with maleic anhydride was studied in detail. The reaction was carried out as bulk polymerisation in a semi-batch process. By this method the compatibility problems of the two monomers, which have very different hydrophilicities could be overcome. The product acts as a very effective fat liquoring agent in leather treatment: the maleic moieties cause an outstanding fixing of the agent on the leather and the fatty crotonate moieties create a very smooth leather. Terpolymers of fatty acrylates, hydrophilic monomers and terpenes could also be synthesized in a similar way. These terpolymers proved to be useful as dispersing agents for pigments in paints and varnishes.