Search results for "HYDROLYSIS"
showing 10 items of 632 documents
Preparation in mild conditions of photocatalytically active nanostructured TiO2 rutile
2006
Abstract Nano structured TiO 2 rutile samples were prepared in mild conditions by hydrolysis of TiCl 4 in different solutions. The powders revealed a fair photoactivity for the photoeatalytic degradation of 4-nitrophenol. The influence of preparation procedure, pH and presence of Cl − and N 3 − anions on the physicochemical features and photocatalytic activity of the powders was investigated.
Rheological Evaluation of Some Commercial Xylanases
2011
The arabinoxylans play and the xylanases play an important role breadmaking. For a better selection of xylanases, it is necessary to understand how they work in breadmaking. At the same activity, the xylanases have different effect on dough rheology. The xylanases activity measured through birch xylan hydrolysis it is not correlated with extensographic effects. Weak but better correlations were observed when the xylanase activity was measured as the ability to decrease the viscosity of soluble wheat arabinoxylans solution.
ChemInform Abstract: Transition Metal Derivatives of Low Oxidation State Phosphorus Oxoacids: Synthetic Pathways and Structural Studies
2010
Abstract A general synthetic approach intended to rationalize the solution preparative chemistry of transition metal phosphites and hypophosphites is presented. As previously shown for other derivatives containing also tetrahedral or pseudotetrahedral oxoanions, the hydrolytic processes affecting the cationic moieties play a determinant role on the very nature of the final solid. In fact, despite the limited number of donor atoms in the anions, the crystal chemistry of these compounds is quite intricate because of both the variety of possible cationic aggregates and the many ways to interconnect them through pseudotetrahedral anionic groups.
Über den angriff des carboniumions am monomeren styrol bei der kationischen copolymerisation von trioxane und styrol. 19. Mitt. über polyoxymethylene
1962
Bei der Saure-katalysierten Hydrolyse von kationisch dargestellten Copolymeren aus Trioxan und Styrol entsteht 4-Phenyl-1,3-Dioxan. Das last sich nur so erklaren, das in Analogie zur radikalischen und zur anionischen Polymerisation der Angriff des Carboniumions ebenfalls am β-Kohlenstoffatom des Styrols erfolgt. Formation of 4-phenyl-1,3-dioxan occurs during the acid catalyzed hydrolysis of cationically produced copolymers of trioxane and styrene. The only possible explanation involves an attack of the carboniumion at the β-carbonatom of styrene analogous to the radical and anionic polymerization.
ChemInform Abstract: Enhanced Surface Area in Thermally Stable Pure Mesoporous TiO2.
2001
Abstract We describe here for the first time the surfactant-assisted synthesis of thermally stable mesoporous pure TiO 2 having a high surface area. Our synthetic approach to the chemistry of this system is based on the equilibrium between the hydrolysis and condensation reactions of the inorganic species and the organic–inorganic self-assembling processes. The use of titanatrane complexes helps to retard the hydrolysis and condensation reactions, thus allowing us to overcome the difficulties in preparing titanium dioxide mesoporous materials starting from highly reactive Ti-alkoxides. The mesoporous material has been characterized by TEM, XRD and N 2 adsorption–desorption isotherms and dis…
Mono- and polynuclear hydroxo complexes of monophenylthallium(III)
1974
Summary The hydrolysis of PhTl(OH)ClO4 has been studied in a medium 0.3 M in NaClO4 by a potentiometric technique. The complexes formed by the hydrolysis reactions together with their formation constants have been determined by the general minimizing computer programme LETAGROP. The hydrolysis species observed in the pH range 3–5 are the mononuclear [(PhTlOH)(OH)], the dinuclear [(PhTlOH)2(OH)]+ and the dimer [(PhTlOH)2(OH)2]. The formation constants are log *β11=−4.92±0.2, log *β21=−1.52±0.03 and log *β22=−6.11±0.05. Stepwise reactions are then postulated whose formation constants are respectively log (*β21/*β11)=3.40±0.25, log (*β22/*β21)=−4.59±0.08 and log (*β22/*β112)=3.73±0.09.
Comparative Analysis of Quality Criteria for the Control of Liquefaction at the Obtaining of Starch-Based Hydrolysates
2012
Starch hydrolysates production converts starch to different kinds of products using enzymes in two steps, liquefaction and saccharification. This study investigated three types of analysis methods for the assessing and characterization of the liquefaction process: a rheological method (to measure yield stress), a chemical method (for the determination of Dextrose Equivalent DE) and a chromatographic method (HPLC to obtain the Degrees of Polymerization DPs). Potato starch with 13.5% dry substance was liquefied with the enzyme Liquozyme Supra for two hours in optimal conditions of pH and temperature. A comparative analysis between the methods to describe the liquefaction process was realise…
Darstellung einer homologen Reihe von oligoallylalkoholen mit 1-cyano-1-methylethyl-endgruppen. Beispiel einer mehrfachen matrizenreaktion und einer …
1984
Reduction and hydrolysis of the ladder oligomers 1, 2, 3, 4, and 5 prepared from the acrylates of oligo (hydroxyphenylene-methylene)s was found to lead to a homologous series of oligo (allylalcohol)s (6a, 7a, 8a, 9a and10a) with good yields. These alcohols were characterized by analytical and spectroscopic methods. The reaction sequences, starting with the esterification of the oligo[(hydroxyphenylene) methylene]s 11a – 11e with acryloyl chloride followed by the formation of the ladder oligomers and ending with their reduction and hydrolysis into the oligo(allyl alcohol)s and the starting compounds 11a – 11e, represent a simple matrix reaction. A mixture of multiple acrylates was also subje…
Some new examples of cationic polymerization
1986
Preparation, proprietes et polymerisation cationique de cis et trans-methoxyvinylchlorure. Le polymere trans est surtout threodiisotactique. Copolymerisation du cis avec le trans ou le styrene ou le dioxolanene-1,3. Polymerisation de la phenyl-2 oxazoline et de la conidine
Synthesis and COX inhibition of 7-R1-8-R2-1-ethyl-3,4-dimethyl-, 4,10-dihydro-1H-pyrazolo[3,4-c][1,5]benzodiazocine-5,11-diones
2008
The title compounds were easily synthesized by reacting the 4-aminopyrazole hydrochloride 2 and the substituted 2-nitrobenzoyl chlorides 3a-d. The obtained 2-nitrobenzamides 4a-d were methylated and then reduced to give the corresponding amines 6a-d. These were hydrolyzed then directly converted into 4,10-dihydro-1H-pyrazolo[3,4-c][1,5]benzodiazocine-5,11-diones 1a-d by the action of SOCl2 in benzene. These were tested for their COX inhibitory activity, showing an inhibitory profile against both COX-1 and COX-2, being slightly more selective against COX-2 with a percentage of inhibition, at the concentration of 10 μM, in the range 42.0 – 55.0.