One‐Step Synthesis of Natural Silk Sericin‐Based Microcapsules with Bionic Structures

Different techniques are being developed for fabricating microcapsules; it is still a challenge to fabricate them in an efficient and environment‐friendly process. Here, a one‐step green route to synthesize silk protein sericin‐based microcapsules without any assistance of organic solvents is reported. By carefully changing the concentration of calcium ions accompanied with stirring, the morphology of the microcapsules can easily be regulated to form either discoidal, biconcave, cocoon‐like, or tubular structures. The chelation of Ca²⁺ and shearing force from agitation may induce the conformational transformation of sericin, which possibly results in the formation of microcapsules through the self‐assembly of the protein subsequently. The as‐prepared cocoon‐like microcapsules exhibit pH‐dependent stability. A potential application of microcapsules being fabricated from natural water‐soluble silk protein sericin for controlled bioactive molecules loading and release system by a pH‐triggered manner is quite feasible.

     

Highly Selective Vapor-Phase Acylation of Veratrole over H_3PO_4/TiO_2-ZrO_2: Using Ethyl Acetate as a Green and Efficient Acylating Agent

A simple sol‐gel method with and without surfactant was applied to prepare TiO₂‐ZrO₂ mixed oxides containing Ti and Zr at a molar ratio of 1:1. Several catalysts containing w=15% –35% H₃PO₄ were set up using these mixed oxides. The physical and chemical properties of catalysts were investigated by BET, SEM and pyridine adsorption‐desorption. The catalytic performance of each material was determined for the vapor‐phase acylation of veratrole (1,2‐dimethoxybenzene) to 3,4‐dimethoxyacetophenone (3,4‐DMAP), which was found to be the major product of the reaction of veratrole with ethyl acetate, with alkylated products being the minor products. 2,3‐Dimethoxyacetophenone (2,3‐DMAP) was not detected in the product stream. In the best experimental conditions, the alkylated products were less than 0.7%. This reaction may represent an environmentally friendly alternative to use the ethyl acetate as the acylating reagent. The feed molar ratios of veratrole/ethyl acetate were varied over a wide range of 0.1 to 1, and the optimum feed ratio of veratrole/ethyl acetate was 1:3. Space velocity employed in the veratrole acylation reported as WHSV (veratrole) was 1.2 h^?1. The acylation reactions were carried out in the temperature range of 423 to 673 K and the optimum H₃PO₄ content for acylation was w=15%.     

环保橡胶油中18种多环芳烃的质谱分析

提出了一种环保橡胶油中18种多环芳烃的GC-MS分析方法,抽提液采用二甲基亚砜,用固相萃取柱净化,由已知浓度的内标溶液定容至1mL后进行质谱分析。以内标法定量,内标物选择12氘代花。18种多环芳烃测定结果的相对标准偏差为2％～31％（n=6）之间,加标回收率在65．44％-108．54％之间。该方法满足环保橡胶油中18种多环芳烃定量分析要求。     

Electro organic synthesis as green and sustainable approach for synthesis of chloro substituted benzyl alcohols

The rising interest in advances of sustainable and greener synthetic approaches has encouraged chemists to investigate novel methods to stimulate organic compounds. The benzyl alcohol and its derivatives are industrially significant chemicals owing to their huge applications in petrochemical industries. In this context a green and sustainable approach for synthesis of Chloro substituted benzyl alcohols has been established. In present research paper cyclic voltammetry study followed by constant current electrolysis and characterization of synthesized 2-Chlorobenzyl alcohol, 3-Chlorobenzyl alcohol, 4-Chlorobenzyl alcohol and 2,4-Dichlorobenzyl alcohol has been reported. Cyclic voltammetry measurements have been employed to setup optimum conditions for electrolysis and to find out electrochemical nature of various Chloro substituted benzaldehydes. Then these results have been judiciary used to carry out electrochemical reduction of various Chloro substituted benzaldehydes using constant current electrolysis. Influence of scan rate and pH on reduction peaks has also been investigated referring irreversible electron transfer phenomenon in basic medium. The kinetic parameters for reduction reactions have been estimated showing the process under the influence of diffusion control. The characterization of electrochemically synthesized 2-Chlorobenzyl alcohol, 3-Chlorobenzyl alcohol, 4-Chlorobenzyl alcohol and 2,4-Dichlorobenzyl alcohol has been done by using spectroscopic techniques such as IR, ¹HNMR and Mass spectral analysis. This has a scientific achievement in terms of the obtained products (2-Chlorobenzyl alcohol, 3-Chlorobenzyl alcohol, 4-Chlorobenzyl alcohol and 2,4-Dichlorobenzyl alcohol) and their derivatives which are industrially and pharmaceutically significant chemicals owing to their huge applications in petrochemical industries and medical sectors. Throat lozenges containing dichlorobenzyl alcohol (DCBA) are used for treatment of respiratory tract infections.     

有关“环境友好塑料”几个概念的澄清

生物塑料、生物降解塑料、生物基塑料统称为环境友好塑料,但它们三者的侧重点各有不同,既有区别,也有联系,本文对以上三个概念的意义做了详细的解释和澄清。生物塑料注重于生产原料的生物来源性和制造过程的生物技术性;生物降解塑料则注重于它是否可以被生物降解,其原料可以来自于可再生资源,也可来自于石油资源;生物基塑料则关注其生产原料是否来自于可再生资源,而对其是否可以生物降解没有特别要求。     

Palladium catalyzed Heck-arylation/cyclization cascade: An environmentally benign and efficient synthesis of 4-arylcoumarins in water

An environmentally benign and efficient approach for the synthesis of 4-arylcoumarins from ortho-hydroxy cinnamate ester derivatives with aryl iodides was developed in water under aerobic conditions. This transformation proceeds through a palladium catalyzed Heck-arylation/cyclization cascade reaction. The present protocol features a wide substrate scope and readily available starting materials to afford the desired products in high to excellent yields.     

Use of an efficient polystyrene‐supported cerium catalyst for one‐pot multicomponent synthesis of spiro‐piperidine derivatives and click reactions in green solvent

One‐pot multicomponent reactions are very demanding in synthetic organic chemistry. Here we report a new polystyrene‐supported cerium catalyst (PS‐Ce‐amtp) obtained via an easy two‐step procedure, which was thoroughly characterized using various techniques. PS‐Ce‐amtp catalyses the environmentally benign one‐pot multicomponent synthesis of spiro‐piperidine derivatives through the reaction of substituted aniline, cyclic active methylene compound and formaldehyde at room temperature. The catalyst also exhibits excellent catalytic activity in one‐pot synthesis of 1,4‐disubstituted 1,2,3‐triazoles via click reaction between in situ generated azides (derived from anilines and amines) and terminal alkynes. The catalyst can be recovered easily after reaction and reused five times without significant loss in its catalytic activity. The advantageous features of this catalyst are atom economy, operational simplicity, short reaction times, easy handling and high recycling efficiency.     

自分层涂料的研究进展

与常规的多次涂膜体系相比,自分层涂料可以实现多层涂膜一次涂装,解决层间附着力差的问题,节约生产成本,提高使用寿命。本文综述了白分层过程及其驱动力,详细讨论了相容性和表面张力等影响自分层的因素,分别从溶剂型、无溶剂型和水性涂料方面阐述了自分层涂料的研究进展。自分层涂料已在众多领域得到了广泛应用,环境友好型自分层涂料是其今...     

Structure and surface properties of polyacrylates with short fluorocarbon side chain: Role of the main chain and spacer group

The degradation of poly(fluoroalkyl acrylate)s with long perfluoroalkyl groups, especially with perfluorooctyl group, leads to the release of biopersistent perfluorooctanoic acid (PFOA) or perfluorooctanesulfonic acid (PFOS). To find the environmentally friendly substitutes, a series of nonbiopersistant fluorinated polymers containing perfluorohexyl groups in the side chains have been synthesized and characterized. This study was then focused on the role played by the main chain and spacer group located in the side chain between the backbone and the fluorinated segment and, in particular, on the properties of poly[2‐[[[[2‐(perfluorohexyl)]‐sulfonyl]methyl]amino]ethyl] acrylate (PC6SA), methacrylate (PC6SMA) and poly[(perfluorohexyl)ethyl] methacrylate (PC6MA). Surface properties and bulk organization of fluorinated side chains of those polymers were investigated by contact angles, differential scanning calorimetry, optical polaring microscopy, and wide‐angle X‐ray scattering. Results were compared with those obtained with poly[(perfluorohexyl) ethyl] acrylate (PC6A). They all had very low surface free energies. Surprisingly, with the same perfluoalkyl chain, PC6SA and PC6SMA with a N‐methylsulfonamide spacer group were found to be organized in a liquid crystalline lamellar structure, whereas PC6A and PC6MA were found to be amorphous. This was mainly attributed to the steric term and polarity of N‐methylsulfonamide group that tended to facilitate the orientation of the perfluorinated segments in smectic phases. PC6SA, PC6SMA, and PC6MA had rich dynamic water repellency because of the low surface molecular mobility. This phenomenon relates to the crystallization of side chains or high glass transition temperature. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2584–2593, 2010     

Diophantine approximation and self-conformal measures

It is proved that the Hausdorff measure on the limit set of a finite conformal iterated function system is strongly extremal, meaning that almost all points with respect to this measure are not multiplicatively very well approximable. This proves Conjecture 10.6 from (on fractal measures and Diophantine approximation, preprint, 2003). The strong extremality of all (S,P)-invariant measures is established, where S is a finite conformal iterated function system and P is a probability vector. Both above results are consequences of the much more general Theorem 1.5 concerning Gibbs states of Hölder families of functions.