Novel Photosynthesis of 5,8a-dichloro-2-(4- Methoxyphenyl)-8ah-chromene from Its Chalcone Isomer And Ft-ir, 1 H And 13 C Nmr Spectroscopic Investigation

In the presence of alcoholic alkali, the base-catalyzed aldol condensation of equimolar quantities of substituted acetophenones and aldehydes to give good yields of condensation product. This reaction is known as the Claisen-Schmidt condensation. The Trans-3-(2,6-dichlorophenyl)-1-(4-methoxyphenyl)prop- 2-en-1-one (trans 2,6-methoxy chalcone) was synthesised by Clasien Schmidt reaction, then it exposed to the Xenon lamp to prepare the 5,8a-dichloro-2-(4-methoxyphenyl)-8aH-chromene (2,6-methoxy chromene). A number of techniques were used to characterise the mentioned two products such as, thin layer chromatography, FT-IR, 1H and 13C nuclear magnetic resonance, liquid chromatography/quadrupole time-of-flight mass spectrometry and elemental analysis (CHNO).

Novel Photosynthesis And Characterization of 4-(5,7- Dichloro-8ah-chromene-2-yl)-n, N-dimethylaniline from Its Chalcone Isomer

In the present study, trans-3-(2,4-dichlorophenyl)-1-(4-(dimethylamino)phenyl)prop-2-en-1-one (trans 2,4-dimethyl amino chalcone) was synthesized by Claisen-Schmidt reaction in the presence of aqueous alcoholic alkali solution by condensation of a substituted acetophenone with substituted benzaldehydes, Then, The photosynthesis of 4-(5,7-dichloro-8aH-chromen-2-yl)-N,N-dimethylaniline (2,4-dimethylamino chromene) was accomplished from the irradiation of the( trans 2,4-dimethyl amino chalcone) with xenon light. The products were characterized by UV-Visible, FT-IR, 1HNMR, thin layer chromatography Elemental analysis(CHNO) and liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-ToF-MS).

Behaviour of pancreatic lipase enzyme during recyclization when synthesizing butyl butyrate in non-aqueous media

Aromatic substances are widely applied in the creation of fragrances for cosmetic, detergent and food products, as well as medical preparations for external use. Environmentally friendly enzymes obtained using green chemistry methods are of particular value. Therefore, the enzymatic synthesis of esters of aromatic aliphatic acids and aromatic alcohols is of great practical interest. This approach has significant advantages over chemical methods, since it is carried out at low temperatures without the formation of byproducts, thus requiring no special purification techniques. Although the cost of enzyme preparations is rather high, immobilized enzymes can be used repeatedly and continuously. In the present work, we investigate the possibility of using non-immobilized freeze-dried lipase (Lipase from porcine pancreas, Type 11) for repeated esterification of butyl alcohol with butyric acid. The synthesis was carried out in hexane. The completeness of the process was controlled by titration of the residual acid with aqueous alcoholic alkali in the reaction medium. The resulting enzyme preparation was separated from the reaction mixture and reused with a new portion of the substrate. It is shown that the obtained enzyme can be used for more than 10 cycles. It was found that, starting from the second cycle, the enzyme activity increases depending on its concentration in the medium. In addition, the butyric acid conversion increases by 6–180% reaching the initial level only after the 10th cycle. The unusual effect of increasing the enzymatic activity of lipase in recycles can be explained by both the phenomenon of autocatalysis, i.e. activation of the enzyme by water released as a result of esterification, and structural features of the active site of pancreatic lipase.

Synthesis, Characterization and Glass - Reinforced Composites of N,N'-Dimethylolthiourea – m-Aminophenol Resin

N,N’-Dimethylolthiourea (DMTU) resin having the methylol group ( –CH2OH ) has been prepared and characterized. The condensation of DMTU resin with m-aminophenol was carried out in the presence of alcoholic alkali catalyst at varying ratios of DMTU: mAP, namely 1:1, 1:1.5 and 1:2. The resultant DMTUmAP resin was characterized by elemental analysis, IR spectral studies, number average molecular weight (M¯n) estimated by non-aqueous conductometric titration, and thermogravimetry. The curing study of DMTUmAP resin with hexamethylenetetramine (HMTA) was monitored by differential scanning calorimetry (DSC) and kinetic parameters were evaluated. Glass-reinforced composites based on the DMTUmAP-HMTA system have also been prepared and characterized.

Synthesis, Characterization and Glass - Reinforced Composites of Thiourea - Formaldehyde - Phenol Resin

N,N'-Dimethylol thiourea-formaldehyde (DMTUF) resin having the methylol group (CH2OH) has been prepared and characterized. The condensation of DMTUF resin with Phenol (P) was carried out in the presence of alcoholic alkali catalyst at varying ratios of DMTUF: P, namely 1:1, 1:1.5 and 1:2. The resultant DMTUFP resin was characterized by elemental analysis, IR spectral studies, number average molecular weight (M¯n) estimated by non-aqueous conductometric titration, and thermo gravimetry. The curing study of DMTUFP resin with hexamethylene tetramine (HMTA) was monitored by differential scanning calorimetry (DSC) and kinetic parameters were evaluated. Glass-reinforced composites based on the DMTUFP-HMTA system have also been prepared and characterized.

Synthesis, Characterization and Glass-Reinforced Composites of Acetone–Formaldehyde–Phenol Resins

Acetone–formaldehyde (AF) resin having the methylol group (–CH2OH) has been prepared and characterized. The condensation of AF resin with phenol (P) was carried out in the presence of alcoholic alkali catalyst at varying ratios of AF:P, namely 1:1, 1:1.5 and 1:2. The resultant AFP resins were characterized by elemental analysis, IR spectral studies, number average molecular weight ( Mn) estimated by non-aqueous conductometric titration, and thermogravimetry. The curing study of AFP resins with hexamethylene tetramine (HMTA) was monitored by differential scanning calorimetry (DSC) and kinetic parameters were evaluated. Glass-reinforced composites based on the AFP–HMTA system have also been prepared and characterized.

The nature of Covalently bound fatty acids in wool fibres

The wool fibre contains a fatty acid component which can only be liberated from the fibre by treatment with alcoholic alkali solutions. The major fatty acid from this component has been isolated in quantity and purified. Using GC/MS and NMR, the fatty acid was identified as 18-methyleicosanoic acid. The results obtained from transesterification experiments suggest that the fatty acid is covalently bound to the fibre protein by an ester linkage.