Search results for "tertiary amine"
showing 10 items of 46 documents
Über die homogene und heterogene acetylierung von polyformaldehyd. 28. Mitteilung über polyoxymethylene1
1966
Die Acetylierung der Endgruppen eines hochmoleckularen Polyoxymethylendiols mit Essigsaureanhydrid wurde bei 200°C in Substanz sowie bei 135°C in Losung und in Suspension untersucht. Die Umsetzung ist in homogenem Medium innerhalb kurzer Zeit praktisch vollstandig; bei 200°C erfolgt jedoch ohne Zusatz eines (tertiaren) Amins eine besonders starke Verminderung der Molekulargewichte und ein Verlust an Polymerem durch Bildung flussiger Oligo-oxymethylendiacetate. Eine fast quantitative Acetylierung ohne Molekulargewichtsverminderung ist durch Umsetzung bei 135°C in Losung unter Zusatz eines tertiaren Amins moglich. Die Veresterungsgeschwindigkeit bei 135°C ist in heterogenem Medium wesentlich …
A capillary liquid chromatography method for benzalkonium chloride determination as a component or contaminant in mixtures of biocides
2015
A method for quantifying benzalkonium chloride (BAK), an alkyl dimethyl benzyl ammonium compound, in several biocides formulations is proposed. A tertiary amine like N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine (TA) and a straight-chain alkyl ammonium compound like trimethyl-tetradecyl ammonium chloride (TMTDAC), have been employed as trade surfactants besides BAK. Two capillary analytical columns with different polarities are tested: inertsil CN-3 capillary column (150mm×0.5mm i.d., 3μm particle diameter) and a non endcapped Zorbax C18 capillary column (35mm×0.5mm i.d., 5μm particle diameter). This latter column provided the best separation of the BAK homologues in less than 12min using …
Intoxication with a tropenol ester.
2012
BACKGROUND While the effects of medicinal products are investigated in depth before approval, often very little is known about the intermediates occurring during synthesis. The pharmacological properties of these intermediates can differ substantially from those of the end product. AIMS To describe a work accident involving intoxication with such an intermediate, tropenol ester. CASE REPORT A healthy 40-year-old chemical-technical operative erroneously used a scrubbing brush that had just been used to clear up tropenol ester, contaminating his work clothes. Presumably, contact was made with his skin when removing his work clothes later. Shortly thereafter, he developed signs of anticholiner…
Considerations on the dipole moment of molecules forming the twisted intramolecular charge transfer state
1992
Several derivatives of dual-fluorescing dimethylaminobenzonitrile (DMABN) are compared regarding their ground and excited-state dipole moments extracted from electro-optical emission and solvatochromic measurements. The comparison includes bridged model compounds as well as compounds with different degrees of steric hindrance to planarity, as well as ester and carbazolyl derivatives. The results are discussed on the basis of the twisted intramolecular charge transfer (TICT) model, the most widely accepted model. They show that (i) the dipole moment of the A (TICT) state (long-wavelength band) shows only little solvent sensitivity (polarizability), (ii) this observed small dependence of the …
Properties of trialkylamines as catalysts of resoles synthesis
2000
A series of the syntheses of phenol–formaldehyde resoles was carried out in the presence of trimethyl-, triethyl-, tripropyl-, and tributylamines and sodium hydroxide as catalysts for this process. The rate constants were calculated for the partial reactions identified in the synthesis. Also, the performance properties of the resins obtained and the hardened resin samples were estimated in simple tests. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 898–902, 2000
17O NMR and molecular mechanical studies of arylmethylenemalonaldehydes
1990
The 17O NMR spectra of six different arylmethylenemalonaldehydes were measured for various solvents and temperatures. The 17O NMR chemical shifts and line widths of the carbonyl oxygens of the malonaldehyde fragment show a clear variation in the series of monoaryl compounds studied. The differences between the 17O NMR chemical shifts of the formyl oxygens correlate well with two conformationally dependent 1H–1H and 1H–13C coupling constants for the same compounds. Molecular mechanical calculations were also performed in order to relate the present data with the conformational preferences of the malonaldehyde fragment of the arylmethylenemalonaldehydes.
Liquid chromatographic determination of trimethylamine in water.
2004
A method for the selective determination of trimethylamine (TMA) in aqueous matrices by liquid chromatography is reported. The proposed procedure is based on the derivatization of the analyte with 9-fluorenylmethyl chloroformate (FMOC) in a precolumn (Hypersil C18, 30 microm, 20 mm x 2.1 mm i.d.) connected on-line to the analytical column (LiChrosphere 100 RP18, 5 microm, 125 mm x 4 mm i.d.). Gradient elution was performed with a mixture of acetonitrile-water-0.05 M borate buffer (pH 9.0). The method has been applied to the direct determination of TMA in water within the 0.25-10.0 microg/ml concentration interval, and can also be adapted to the determination of TMA over the range 0.05-1.0 m…
A fluorescent molecular sensor for pH windows in traditional and polymeric biocompatible micelles: comicellization of anionic species to shift and re…
2011
A new approach is presented to obtain fluorescent sensors for pH windows that work in water and under biomimetic conditions. A single molecule that features all-covalently linked components is used, thus making it capable of working as a fluorescent sensor with an OFF/ON/OFF response to pH value. The components are a tertiary amine, a pyridine, and a fluorophore (pyrene). The forms with both protonated bases or both neutral bases quench the pyrene fluorescence, whereas the form with the neutral pyridine and protonated amine groups is fluorescent. The molecular sensor is also equipped with a long alkyl chain to make it highly hydrophobic in all its protonated and unprotonated forms, that is,…
Novel Multifunctional Polymeric Photoinitiators and Photo-Coinitiators Derived from Hyperbranched Polyglycerol
2007
A new class of hyperbranched PPIs and PPCs have been prepared. The introduction of compatibilizing groups such as MEEA or trimethylacetate enhanced their solubility in radiation-curable formulations and led to an improved photoactivity compared with the corresponding MPI and MPC. Although the molecular weights of the subject PPIs and PPCs exceeded 800 g mol -1 , the viscosities of the radiation-curable formulations were still suitable for inkjet application. The combination of high photoactivity, low viscosity, and low extract-ability after curing rendered the resulting hyperbranched PPIs and PPCs attractive as components in the inkjet ink for inkjet printing, e.g., in food packaging.
Ring size control in diorganotin sulphides by intramolecular SnN coordination
1992
Abstract The synthesis of intramolecularly coordinated organotin sulphides, [(Me2N CH2CH2CH2)2SnS]n (1) and [Me2NCH2CH2CH2Sn(Ph)S]n (2), is described. Compounds 1 and 2 are dimers in chloroform solution (n = 2). Compound 1 forms a centrosymmetric dimer with a planar rectangular Sn2S2 four-membered ring in its centre. The tin atoms show a distorted trans-cis-cis octahedral coordination by 2C, 2N and 2S. The tin-nitrogen distances are 2.810(3) and 3.158(5) A. Compound 1 can be regarded as a model substance for nucleophilic attack at penta-coordinate tin centres. Although the degree of intramolecular coordination of nitrogen to tin is temperature dependent, the four-membered Sn2Sn2 ring remain…