Untersuchungen zum UV/Vis-Spektralverhalten von Azofarbstoffen. XVIII. Substituenteneinflüsse auf die Absorptionsmaxima der n → π*– und π → π*-Banden von 4-N,N-Diethylaminoazobenzenen

Studies on UV/Vis Absorption Spectra of Azo Dyes. XVIII. Substituent Effects on the Absorption Maxima of the n → π^* and π → π^* Bands of 4-N,N-Diethylaminoazobenzenes The spectra of 27 substituted 4-N.N-diethylaminoazobenzenes are determined. The band systems can be separated by deconvolution into two Gaussian curves. The results so obtained show that the effects of substituents on n → π^* and π → π^* transitions are similar and that electron withdrawing substituents in the phenylazo residue cause a bathochromic shift of both the n → π^* and the π → π^* bands.     

Synthese und π-Elektronenstruktur von 2,5-Bis-alkylamino-terephthalsäurediethylestern

Synthesis and π-Electronic Structure of 2,5-Bis(alkylamino)-terephthalic Acid Diethyl Ester 2,5-Dioxocyclohexane-1,4-dicarboxylic acid diethyl ester 1 reacts with primary alkylamines 2 to 2,5-bis-(alkyl-amino)-cyclohexa-1,4-diene-1,4-dicarboxylic acid diethyl ester 3 . The dehydrogenation of 3 by means of bromine or chloranil leads to 2,5-bis(alkylamino) terephthalic acid diethyl ester 4 . Electronic spectra and quantumchemical calculations according the SCF-LCI method indicated that the absorption proporties of 4 in the visible spectral region follow the general pattern of substituted aromatic compounds. A merocyanine-like electronic structure seems to be less probable.     

Strukturabhängige Eigenschaften von Tensiden,untersucht an Reihen von 2-Alkylsulfaten,Phosphinoxiden und ω-H-Perfluorverbindungen

Structure-Dependent Properties of Detergents as Studied at 2-Alkylsulphates, Phosphine-oxides, and ω-H-Perfluoroalkyl Compounds CMC values from δ/lg c-curves were determined for the homologous series of 2-alkyl-branched alkylsulphates, dimethyl- an diethyl-phosphine-oxides and ω-H-perfluoroalkyl-sulfosuccinates. On this basis effective chainlengths were calculated and correlated with other properties as maximum of surface tension depression, wettability and foaming.     

Die Fokker‐Planck‐Gleichung zur Beschreibung von axialen Transport‐ und Mischvorgängen in Rohrreaktoren

One way to explain the mechanism of powder mixing is the Fokker‐Planck equation. The equation comprises two decisive parameters, the transport coefficient U that depends on the active transport of the mixing device and the dispersion coefficient D which describes the mobility of the single particles. The idea is to calculate the dispersion and transport coefficient by using the powder characteristics. To verify this assumption, measurements with different components and different rotation speeds were made.     

PROBAD – Programmsystem zur Festigkeitsberechnung von Behältern,Apparaten und Dampf-Erzeugern

PROBAD – A program system for stress calculations on vessels, equipment, and steam generators . The PROBAD program system performs stress calculations according to TRD Rules, AD Codes, DIN Standards, as well as ASME Code Sec. VIII Div. 1 and TEMA Standards. Starting from given assemblies, whole vessels or parts thereof are designed or checked. Moreover, the PROBAD language also permits supplementary assignment of user-specific and standard values to the system without any need for direct modification of the program system. The input and output can likewise be set up in a user-specific manner.     

Nachweis von ω-Aminocarbonsäuren und Carbonylverbindungen in thermooxidativ abgebautem Polycaprolactam

After oxidation and subsequent hydrolysis homologous series of alkyl amines and ω-amino carboxylic acids were proved to be further degradation products of polycaprolactam. The formation of these substances cannot be explained by an attack on the N-vicinal methylene group which is the most reactive site of this polymer. Considering the low and nearly equal amount of nitrogen containing degradation products a statistical attack on the remaining methylene groups takes place besides the preferred N-vicinal reaction. The CO-vicinal site is not particularly activated. The formation of likewise isolated substances with carbonyl groups cannot be explained by a uniform mechanism.     

Zur Gasphasenpyrolyse von α, ω-Phenylalkenen – Gesetzmäßigkeiten und Besonderheiten

On the Gas Phase Pyrolysis of α, ω-Phenylalkenes — Regularities and Special Features The thermal conversion of the α, ω-phenyl alkenes 1 to 4 was studied in the presence of a molar excess of Ar or steam at 500 to 875°C in a labscale tubular reactor. Detailed GC analyses did not establish significant evidences for such molecular rearrangements like, e.g., Di-π-methane rearrangement of 2 , Ene and Carbo-Claisen reaction of 3 . The decomposition obviously occurs via radical chain processes in the main. Besides them, however, radical cyclizations, Neophyl rearrangements and Retro-Ene reactions are parts of the complex reaction.     

1H- und 13C-NMR-spektroskopische Messungen und MO-Berechnungen zur π-Elektronenstruktur von p,p′-disubstituierten trans-Stilbenen und substituierten trans-β-Styryl-methyl-sulfonen

¹H and ¹³C n.m.r. Spectroscopical Measurements and HMO-π-Calculations to the π-Electronic Structure of p,p′-Disubstituted trans-Stilbenes and Substituted trans-β-Styryl-methyl-Sulfones The ¹H and ¹³C n.m.r. spectra have been measured for a series of donator-acceptor-disubstituted trans-stilbenes 1 and monosubstituted β-styryl-methyl-sulfones 2 . The ¹³C n.m.r.-signals have been identified by comparison with empirical calculated chemical shifts and quantum chemical determined HMO-π-electrons densities. The influence of substitutents to the experimental chemical shifts are discussed in detail. For 1 and 2 exist linear correlations between chemical shifts and HAMMETT values, and π-electron densities, respectively.     

ω-3- und ω-6-Fettsäuren – Biochemische Besonderheiten und biologische Wirkungen

ω-3- and ω-6-Fatty Acids – Biochemical Specialities and Biological Effects ω-6- and ω-3-fatty acids are essential for mammals and human beings. Deficiency symptoms of ω-6- and ω-3-fatty acids are known in infants and adults. In higher doses ω-6-and ω-3-fatty acids produce biological effects, which can have positive or negative consequences. Therefore a well balanced supply of these fatty acids must be considered. By a mixed diet according to the recommendations of the German Nutrition Society a sufficient supply with ω-6- and ω-3-fatty acids will be possible. In the present state of knowledge an uncontrolled medication of fish oil capsules cannot be recommended, but an increase of the present intake of salt water fish with a favourable type of fat and other useful nutrients like iodine, selenium et. is desirable.     

1H- und 13C-NMR-Spektren von N-Methyl-chinoliniumchalkonen: Bestimmung von σ-Konstanten für die 2-, 3- und 4-Position des N-Methyl-chinoliniumrings

¹H- and ¹³C-N.M.R. Spectra of N-Methyl-quinolinium Chalcones: Determination of σ-Constants for the 2-, 3- and 4-Position of the N-Methyl-quinolinium Ring For the N-methyl-quinolinium chalcones 1a – c the ¹H- and ¹³C-n.m.r. data are reported. The unambiguous assignment of signals is based upon the ¹H/¹H homoshift and the ¹³C/¹H heteroshift correlated 2D-n.m.r. spectra. Using a Hammett relationship we have determined σ-constants for the 2-, 3- and 4-position of the N-methyl-quinolinium ring from the ¹³C-α chemical shifts of 1a – c . Their comparison with the σ-values for the equivalent positions in the pyridine, N-methyl-pyridinium and quinoline ring indicates the additivity of anellation and quaternization effect.