Month: November 2022

Desai, Umang published the artcileA comparison of evolution of adhesion mechanisms and strength post damp-heat aging for a range of VA content in EVA encapsulant with photovoltaic backsheet, Application In Synthesis of 52829-07-9, the main research area is ethylene vinyl acetate film fabrication adhesion strength.

Ethylene vinyl acetate (EVA) is an effective encapsulant to adhere various layers in the photovoltaic (PV) module. In this study, we have fabricated EVA films containing different vinyl acetate (VA) content (18%, 24%, 33% and 40%) and laminated between two layers of backsheet (BS). These laminates have been subjected to damp-heat (DH) ageing at 85OC and 85% relative humidity (RH) for 1000 h to evaluate the change in adhesion strength at EVA/BS interface using the T-peel test. The adhesion strength for EVA containing 18% VA content has been found to improve but it deteriorates for EVA with 33 and 40% VA content after ageing. However, adhesion strength for EVA containing 24% VA content is found unaffected after ageing. The degree of crosslinking and VA content have been determined through gel content measurement and thermo-gravimetric anal. (TGA) resp. The degree of crosslinking and VA content increases significantly in EVA18 but decreases in EVA40 due to DH ageing. The chem. changes have been examined by the Fourier transform IR spectroscopy (FTIR) and the XPS. The failure mode (cohesive or delamination) at the interface and its correlation with the adhesion strength has been explored using XPS. The failure mode at the EVA18/BS interface alters from delamination type in pristine condition to the cohesive type due to DH ageing. However, the failure mode for EVA24 and EVA40 is found to be cohesive in both the pristine and aged condition.

Solar Energy published new progress about Adhesion, physical, interfacial. 52829-07-9 belongs to class piperidines, name is Bis(2,2,6,6-tetramethylpiperidin-4-yl) decanedioate, and the molecular formula is C28H52N2O4, Application In Synthesis of 52829-07-9.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Freifelder, Morris published the artcileNuclear magnetic resonance spectra of some N-substituted methylamines. II. Effect of acidic conditions, Quality Control of 1690-74-0, the main research area is .

cf. CA 64, 4478f. The N.M.R. spectra of a number of N-substituted methylamines in acidic media are examined Among those studied–RNHCH3 (R is alkyl, aralkyl, cyclic, or cycloalkyl)–the N-methyl signal is a triplet (J = 5.5 cps.) when the spectra are run in various solvents to which hydrochloric acid is added to pH 1.0 or below. Under similar conditions, the spectra of tertiary N-methylamines, where one of the above R groups is substituted for H, show the N-methyl signal as a doublet (J = 4-5.5 cps.). Splitting of the signal among saturated N-methyl heterocycles is observed in strongly acidified solvent only when one N atom is part of the heterocyclic system. In neutral solvent, the spectra of the aforementioned compounds show a single peak for the N-methyl protons in every instance. In the piperazine series, if one ring N is acylated and the spectrum of the 1-acyl-4-methylpiperazine is ran in trifluoroacetic acid, the N-methyl signal is seen as a doublet, otherwise a single peak is noted among other N-methylpiperazines. An attempt is made to classify N-substituted methylamines by means of the N-methyl signal in their spectra in neutral solvent and various acidic media.

Journal of Organic Chemistry published new progress about NMR (nuclear magnetic resonance). 1690-74-0 belongs to class piperidines, name is Methyl 1-methylpiperidine-2-carboxylate, and the molecular formula is C8H15NO2, Quality Control of 1690-74-0.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Blazquez-Blazquez, Enrique published the artcileIdentification of Additives in Polypropylene and Their Degradation under Solar Exposure Studied by Gas Chromatography-Mass Spectrometry, COA of Formula: C28H52N2O4, the main research area is polypropylene additive solar gas chromatog.

Additives are absolutely essential in the development of com. polymeric materials. Accordingly, an exhaustive control of composition and evolution in these additives over time is necessary to validate their performance and safety during their shelf life and, consequently, their ultimate applications. Gas chromatog. coupled with mass spectrometry, GC-MS, is described in the present work to identify and analyze the content of a wide variety of additives, commonly used in industrial polymeric materials. First, the identification under the present exptl. protocol of additives with a relatively high mol. weight (Irganox 1330 and Irganox 1010) has been successfully attained. Second, the evolution under solar exposure over time has been analyzed by GC-MS for 11 additives and derived substances have been identified in a com. polypropylene sample, estimating the corresponding depletion times. In addition, the resultant increase of carbonyl groups in the polymeric macrochains along the photo-oxidation has been also determined by IR spectroscopy. Therefore, GC-MS is found to be a reliable tool for the anal. of the evolution of commonly used polymer additives under specific degradation conditions, which can be very useful in the formulation of improved future additivations.

ACS Omega published new progress about Environmental polymer degradation. 52829-07-9 belongs to class piperidines, name is Bis(2,2,6,6-tetramethylpiperidin-4-yl) decanedioate, and the molecular formula is C28H52N2O4, COA of Formula: C28H52N2O4.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Desai, Umang published the artcileEnhancement of resistance against damp heat aging through compositional change in photovoltaic encapsulant poly (ethylene-co-vinyl acetate), Application In Synthesis of 52829-07-9, the main research area is polyethylene vinyl acetate copolymer resistance damp heat photovoltaic encapsulant.

The most common encapsulant used in the photovoltaic (PV) modules is poly (ethylene-co-vinyl acetate) (PEVA). The characteristics of PEVA can be varied by modulating its vinyl acetate (VA) content. According to the general consensus within the PV industry, PEVA as an encapsulant should have VA content between 28 and 33%. Degradation of PEVA films due to environmental stressors like humidity, temperature and solar radiation in the field aged modules is not uncommon. Moreover, degradation of PEVA encapsulant implies a concomitant loss in the elec. performance of the PV modules. VA content modulation especially outside the most commonly used and accepted range has been tried in this study to improve the damp heat aging resistance of PEVA films. PEVA films containing 18, 24, 33, and 40% VA content with the necessary additives have been fabricated and cured at 150°C under vacuum and subsequently subjected to accelerated damp-heat (85°C and 85% RH) aging according to IEC 61215 standard for 1000 and 2000 h. Tensile strength, thermal stability and degree of crosslinking have been found to be greater for PEVA containing lower VA content (18 and 24%) and diminished for PEVA with higher VA content (33 and 40%) due to DH aging. However, inadequate % transmittance and relatively high stiffness after 2000 h of DH aging discourages PEVA18 as an encapsulant. Moreover, PEVAs with higher VA content (33 and 40%) have been degraded significantly after 2000 h of DH aging resulting in significant loss in transmittance and mech. integrity. Therefore, the results of this investigation encourage the PV industry to reduce the VA content in PEVA down to 24% for better encapsulation response against DH aging.

Solar Energy published new progress about Differential scanning calorimetry. 52829-07-9 belongs to class piperidines, name is Bis(2,2,6,6-tetramethylpiperidin-4-yl) decanedioate, and the molecular formula is C28H52N2O4, Application In Synthesis of 52829-07-9.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Li, Meng published the artcileCopper-Catalyzed 3-Positional Amination of 2-Azulenols with O-Benzoylhydroxylamines, Quality Control of 73874-95-0, the main research area is azulenol benzoylhydroxylamine copper catalyst regioselective amination; aminoazulenol preparation.

A copper-catalyzed ortho-selective amination of 2-azulenols with O-benzoylhydroxylamines (RR’N-OBz) to synthesize ortho-aminoazulenols was reported. A wide range of functional groups on amines were compatible, furnishing the corresponding amino-azulene derivatives in moderate to good yields. The further synthetic elaboration using 3-amino-2-azulenols as starting materials was demonstrated.

Organic Letters published new progress about Amination catalysts (regioselective). 73874-95-0 belongs to class piperidines, name is tert-Butyl piperidin-4-ylcarbamate, and the molecular formula is C10H20N2O2, Quality Control of 73874-95-0.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Kang, Qi-Kai published the artcileRu(II)-Catalyzed Amination of Aryl Fluorides via η6-Coordination, Related Products of piperidines, the main research area is fluorobenzene amine diphenyl phosphane ruthenium catalyst regioselective amination; aminobenzene preparation.

A Ru/hemilabile-ligand catalyzed nucleophilic aromatic substitution (SNAr) of aryl fluorides as the limiting reagents was developed. Significant ligand enhancement was demonstrated by the engagement of both electron-rich and neutral arenes in the SNAr amination without using excess arenes. Preliminary mechanistic studies revealed that the nucleophilic substitution proceeds on a η6-complex of the Ru-catalyst and the substrate, and the hemilabile ligand facilitated dissociation of products from the metal center.

Journal of the American Chemical Society published new progress about Amination catalysts (regioselective). 73874-95-0 belongs to class piperidines, name is tert-Butyl piperidin-4-ylcarbamate, and the molecular formula is C10H20N2O2, Related Products of piperidines.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Chang, Chia-Wei published the artcileThe effects of adding different HALS on the curing process, film properties and lightfastness of refined oriental lacquer, Related Products of piperidines, the main research area is hindered amine stabilizer curing lightfastness oriental lacquer film property; hindered amine light stabilizers; laccase-catalyzed reaction; oriental lacquer; oxidative polymerization.

Oriental lacquer is a natural polymeric coating with a satiny texture and excellent characteristics, such as chem. resistance and durability. However, the poor lightfastness resulted in the natural aromatic structures of the urushiol structures limited its suitability for outdoor application. This study aimed at the improvement of the lightfastness by adding the different hindered amine light stabilizers (HALS) with 2 phr addition as well as the effects on the coating and film property of the refined oriental lacquers (RL). The Cryptomeria japonica plate, glass sheets, and the other substrates were used for finishing. The results showed that the lightfastness of RL film was obviously improved by adding 2 phr HALS of Bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (H90) containing -NH group and Bis (1,2,2,6,6-pentamethyl-4-piperidinyl)-[[3,5-bis(1,1-di-Me ethyl) -4-hydroxyphenyl] methyl] butylmalonate (H60) containing -NCH3 groups. The HALS additions increased the pH value of RL and improved the activities of laccase-catalyzed reaction. Meanwhile, the oxidative polymerization of the side chains of RL was inhibited, caused by a radical scavenging ability of HALS. The changes in the drying process affected not only the curing time, but also the film properties. Among the 2 phr additions of different HALS, the film containing H90 had the best lightfastness. Meanwhile, it kept the most similar properties with RL and shortened the drying time of RL, and it was selected as the best HALS addition under 2 phr in this study.

Polymers (Basel, Switzerland) published new progress about Abrasion-resistant coating materials. 52829-07-9 belongs to class piperidines, name is Bis(2,2,6,6-tetramethylpiperidin-4-yl) decanedioate, and the molecular formula is C28H52N2O4, Related Products of piperidines.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Wanner, Benedikt published the artcileCatalytic Kinetic Resolution of Disubstituted Piperidines by Enantioselective Acylation: Synthetic Utility and Mechanistic Insights, Application of 1-N-Boc-2-Ethylpiperidin-4-one, the main research area is piperidine nonracemic preparation; kinetic resolution piperidine acylation nonracemic indanooxazinol hydrocinnamate; dependence acylation enantioselectivity stereochem disubstituted piperidine; transition state model enantioselective acylation piperidine nonracemic indanooxazinol hydrocinnamate; nitrophenylsulfonyl benzylethylpiperidine mol crystal structure.

Resolution of 2,3-, 2,4-, and 2,5-disubstituted piperidines using either a nonracemic hydroxamate ester I (R = 4-MeOC6H4) or using an unsaturated α-hydroxy-α’,β’-unsaturated ketone in the presence of a nonracemic hydroxamate and a pyrrolotriazolium N-heterocyclic carbene precursor yielded N-acylated piperidines and nonracemic piperidines with practical selectivity factors (s, up to 52). The selectivity of resolution depended strongly on the conformation of the piperidine reactants, with cis-2,3- and 2,5-disubstituted piperidines and trans-2,4-disubstituted piperidines being resolved more effectively than trans-2,3- and 2,5-disubstituted and cis-2,4-disubstituted piperidines. The method was also used for the resolution of 2-substituted 4-methylenepiperidines and 2-substituted 4-piperidinone ethylene and propylene ketals. Detailed exptl. and computational studies of the kinetic resolution of various disubstituted piperidines revealed a strong preference for the acylation of conformers in which the α-substituent occupies the axial position. This work provides further exptl. and computational support for the concerted 7-membered transition state model for acyl transfer reagents and expands the scope and functional group tolerance of the secondary amine kinetic resolution The structure of a nonracemic (nitrophenylsulfonyl)benzylethylpiperidine was determined by X-ray crystallog.

Journal of the American Chemical Society published new progress about Acylation catalysts (stereoselective). 324769-07-5 belongs to class piperidines, name is 1-N-Boc-2-Ethylpiperidin-4-one, and the molecular formula is C12H21NO3, Application of 1-N-Boc-2-Ethylpiperidin-4-one.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Dou, Zhe published the artcileKinetic resolution of nearly sym. 3-cyclohexene-1-carboxylate esters using a bacterial carboxylesterase identified by genome mining, Synthetic Route of 1690-74-0, the main research area is kinetic resolution carboxyesterase enzymic hydrolysis.

A new bacterial carboxylesterase (CarEst3) was identified by genome mining and found to efficiently hydrolyze racemic Me 3-cyclohexene-1-carboxylate (rac-CHCM) with a nearly sym. structure for the synthesis of (S)-CHCM. CarEst3 displayed a high substrate tolerance and a stable catalytic performance. The enantioselective hydrolysis of 4.0 M (560 g·L-1) rac-CHCM was accomplished, yielding (S)-CHCM with a >99% ee, a substrate to catalyst ratio of 1400 g·g-1, and a space-time yield of 538 g·L-1·d-1.

Organic Letters published new progress about Enantioselective biochemical synthesis. 1690-74-0 belongs to class piperidines, name is Methyl 1-methylpiperidine-2-carboxylate, and the molecular formula is C8H15NO2, Synthetic Route of 1690-74-0.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem

Anil Kumar, K. S. published the artcileSynthesis and identification of chiral (aminomethyl)piperidine carboxamides as inhibitor of collagen induced platelet activation, Synthetic Route of 132431-09-5, the main research area is antithrombotic anticoagulant; Aminomethylpiperidine; Antiplatelet; Collagen; Epinephrine; Pyroglutamic acid; Thrombosis.

Several chiral lactam carboxamides of (aminomethyl)piperidine were synthesized and investigated for a collagen induced in vitro anti-platelet efficacy and collagen plus epinephrine induced in vivo pulmonary thromboembolism. One compound (30 μM/kg) displayed a remarkable antithrombotic efficacy (60% protection) which was sustained for more than 24 h and points to its excellent bioavailability. Other compounds (IC50 = 6.6 μM, IC50 = 37 μM), as well as their racemic mixture (IC50 = 16 μM) significantly inhibited collagen-induced human platelet aggregation in vitro. One compound displayed a dual mechanism of action against both collagen (IC50 = 3.3 μM) and (5Z)-7-[(1R,4S,5S,6R)-6-[(1E,3S)-3-hydroxy-1-octen-1-yl]-2-oxabicyclo[2.2.1]heptyl]-4-heptenoic acid (U46619) (IC50 = 2.7 μM) induced platelet aggregation. A pharmacokinetic study indicated faster absorption, prolonged and constant systemic exposure and thereby exhibiting better therapeutic response. The synthesis of the target compounds was achieved using 5-oxo-L-proline esters (pyroglutamic acid esters) and analogs, such as 2-oxo-4-oxazolidinecarboxylic acid ester, 2-oxo-4-thiazolidinecarboxylic acid ester, (2S)-6-oxo-2-piperidinecarboxylic acid ester and morpholine analogs as reactants. The title compounds thus formed included N-[[(3S)-1-[[(2S)-1-[(4-methylphenyl)methyl]-5-oxo-2-pyrrolidinyl]carbonyl]-3-piperidinyl]methyl]carbamic acid ester and related substances, such as an epimer N-[[(3R)-1-[[(2S)-1-[(4-methylphenyl)methyl]-5-oxo-2-pyrrolidinyl]carbonyl]-3-piperidinyl]methyl]carbamic acid ester and related substances..

European Journal of Medicinal Chemistry published new progress about Anticoagulants (antithrombotic agents). 132431-09-5 belongs to class piperidines, name is Benzyl (piperidin-4-ylmethyl)carbamate, and the molecular formula is C14H20N2O2, Synthetic Route of 132431-09-5.

Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem