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•Alkali de-esterification increased negative charges and decreased molecular weight of HMP.•HG content decreased while RG-I increased after alkali de-esterification.•HMP with ...different DE has similar structural characteristic in FTIR, 1H NMR and XRD.•Gel property and emulsifying capacity of HMP decreased with the decrease of DE.
Moderate alkali de-esterification can change the physicochemical characteristics and thus the functional properties of high methoxyl pectin (HMP). The results revealed that de-esterification could increase negative charges (Zeta potential from −21 to −31 mV), decrease molecular weight (from 448 to 136 kDa) and apparent viscosity of HMP. Homogalacturonan (HG) content decreased (from 62% to 49%) while rhamnogalacturonan Ⅰ (RG-Ⅰ) content increased (from 32% to 46%) after de-esterification. The group characteristics of HMP with different degree of esterification (DE) were similar and no obvious impact was made on degree of crystallinity by alkali de-esterification. A conformation transition of HMP molecule implied by Congo red test were occurred as the DE decreased. With the decrease of DE, the molecular structure of HMP became shorter and smaller, and the entanglement was weaker. The de-esterification caused slight decrease of thermal stability. Alkali de-esterification would weaken the gel property and the emulsifying ability of HMP.
Correction for 'DCID-mediated esterification of carboxylic acids with alcohols under mild conditions' by Farzaneh Nasiri
et al.
,
RSC Adv.
, 2023,
13
, 27385-27390,
https://doi.org/10.1039/d3ra04048h
....
Judicious tailoring of the interface between the SnO2 electron‐transport layer and the perovskite buried surface plays a pivotal role in obtaining highly efficient and stable perovskite solar cells ...(PSCs). Herein, a DL‐carnitine hydrochloride (DL) is incorporated into the perovskite/SnO2 interface to suppress the defect‐states density. A DL‐dimer is obtained at the interface by an intermolecular esterification reaction. For the SnO2 film, the Cl− in the DL‐dimer can passivate oxygen vacancies (VO) through electrostatic coupling, while the N in the DL‐dimer can coordinate with the Sn4+ to passivate Sn‐related defects. For the perovskite film, the DL‐dimer can passivate FA+ defects via hydrogen bonding and Pb‐related defects more efficiently than the DL monomer. Upon DL‐dimer modification, the interfacial defects are effectively passivated and the quality of the resultant perovskite film is improved. As a result, the DL‐treated device achieves a gratifying open‐circuit voltage (VOC) of 1.20 V and a champion power conversion efficiency (PCE) of 25.24%, which is a record value among all the reported FACsPbI3 PSCs to date. In addition, the unencapsulated devices exhibit a charming stability, sustaining 99.20% and 90.00% of their initial PCEs after aging in air for 1200 h and continuously operating at the maximum power point tracking for 500 h, respectively.
DL‐Carnitine hydrochloride (DL) is incorporated into the perovskite/SnO2 interface for FACsPbI3 perovskite solar cells (PSCs). Oxygen vacancies and Sn‐related defects are concurrently suppressed by the DL, while the DL‐dimer yielded by the intermolecular esterification passivates Pb‐related defects more efficiently than DL. Consequently, a DL‐treated device achieves a record efficiency of 25.24% among all the reported FACsPbI3 PSCs to date.
In recent years, methyl formate has received considerable attention as an ideal and green C1 building block to synthesize carboxylic esters. However, examples of a one-step route to esters with ...one-carbon elongation using methyl formate as a source of methoxycarbonyl radical are still rare. Herein, we present peroxide-induced radical carbonylation of
-(2-methylallyl)benzamides with methyl formate as the precursor of methoxycarbonyl radical and RuCl
as catalyst, affording a series of biologically valuable 4-(methoxycarbonyl)methyl-3,4-dihydroisoquinolinones with good tolerance and insensitivity to moisture in one pot under simple and mild conditions.
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•A new biomass-based graphene-like photothermal catalyst S-NGL-600 was simply prepared.•Response surface methodology optimized microalgae biodiesel production (96.8 % yield)•Infrared ...thermal imaging indicated formation of a local photothermal catalytic system.•Light-to-heat favored removal of in situ formed water to enable biodiesel synthesis.•LCA showed superior eco-friendliness of light-enhanced microalgae-to-biofuel process.
Thermocatalytic (trans)esterification of oils/lipids to produce biodiesel is generally energy-consuming, reversible, and controlled by the equilibrium law. Herein, a light-induced photothermal process was illustrated to be highly efficient for biodiesel production (96.8 % yield) from microalgae lipids at room temperature enabled by a biomass-based SO3H-functionalized graphene-like heterogeneous catalyst (S-NGL-600), as optimized by response surface methodology. Infrared thermal imaging indicated that interfacial solar heating led to forming a local photothermal catalytic system, reaching 72.2 °C in 2 min. The local light heating was conducive to evaporation and removal of water from acid sites, resulting in local excess of microalgae lipids to facilitate the forward reaction. Notably, the photothermal catalyst was highly recyclable and exhibited a significantly higher conversion rate of microalgae lipids than industrially used catalyst H2SO4. Life cycle assessment suggested energy-saving advantage (0.87 MJ/MJ) and environmental protection (-89.42 CO2eq/MJ) of the photothermal-driven protocol for microalgae biodiesel production.
Phytosterols are structurally similar to cholesterol but they are much less absorbed (<2%) than cholesterol (>50%) in the intestine. We hypothesize that phytosterols are poor substrates of intestinal ...acyl-CoA: cholesterol acyltransferase 2 (ACAT2), and thus minimal phytosterol esters are formed and packed into chylomicrons, leading to their low absorption. Two isotope tracing models, including a radioactive hamster microsomal ACAT2 reaction model and a differentiated Caco-2 cell model, were established to examine the specificity of ACAT2 to various sterols, including cholesterol, sitosterol, stigmasterol, and campesterol. Both models consistently demonstrated that only cholesterol but not phytosterols could be efficiently esterified by ACAT2 in a time- and dose-dependent manner. Molecular docking further suggested that unfavorable interactions existed between ACAT2 and phytosterols. In conclusion, phytosterols are poor substrates of ACAT2 and thus minimally absorbed. This work provides a theoretical basis for the use of phytosterol-based supplements in treating dyslipidemia and preventing heart diseases.
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•An “esterification theory” is proposed to explain sterol absorption selectivity.•Phytosterols, unlike cholesterol, are poor substrates for hamster intestinal ACAT2.•Caco-2 cells can only efficiently esterify cholesterol but not plant sterols.•Unfavorable interactions may exist between ACAT2 and phytosterols.•ACAT2 limits the esterification and thus the absorption of phytosterols.
Bentonite, a readily available and abundant natural mineral, serves as a cost-effective catalyst for esterifying free fatty acids (FFAs). In this study, an economical method was developed to enhance ...the catalytic activity of Chocolate bentonite (Ca-CB) from Paraíba, Brazil, for the methyl esterification of distilled deodorized palm oil (DDPO), an agro-industrial by-product containing approximately 84 % FFAs. Raw bentonite and activated material were characterized using various techniques, including nitrogen physisorption, X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA)/differential thermogravimetry (DTG), scanning electron microscopy (SEM), and acid-base titration. The highest conversion rate of 93 % was achieved using H-Ca-CB in the esterification of DDPO, surpassing H-Na-Ca-CB (91 %) and the commercially available K-10 catalyst (81 %). Furthermore, H-Ca-CB maintained superior catalytic activity (over 75 %) even after four reuse cycles, outperforming autocatalysis (34 %). Kinetic studies of the transesterification process indicated that the pseudo-first-order model was the most suitable, with an activation energy of 27.40 kJ mol–1. These findings underscore the effectiveness of natural bentonite in catalytic synthesis, attributed to its enhanced textural properties and surface acidity.
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Because of the electron-rich property of indoles, direct functionalization strategies towards indoles generally involve electrophilic substitutions. In this paper, an efficient protocol for ...nucleophilic hydroxylation, halogenation and esterification of indoles
the aromatic Pummerer process was developed. With the advantages of readily accessible starting materials, simple operation and mild conditions, this protocol should be of interest to synthetic scientists.
This review paper provides an overview of the main strategies for the oxidative esterification of thiols with alcohols. The review is divided into two major parts according to final products. The ...first includes the methods for the synthesis of sulfinic esters, while the second contains the procedures for the fabrication of sulfonic ester derivatives.
This review paper provides an overview of the main strategies for the oxidative esterification of thiols with alcohols.
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