GRAFTING OF PEROXIDE-INITIATED MALEIC ANHYDRIDE ON SPHERICAL PE／PP IN-REACTOR BLEND GRANULES

Spherical polyethylene/polypropylene (PE/PP) in-reactor blend granules with various ethylene/propylene molar ratios and high porosity were synthesized using a high yield TiCl4/MgCl2 supported catalyst. A solution of benzoyl peroxide (BPO)/maleic anhydride (MAH)/xylene (interfacial reagent) or BPO/MAH/St (comonomer) was absorbed onto the PE/PP inreactor blend granules, and solid phase gratt polymerization of MAH on PE/PP was conducted. The amount of grafted MAH on PE/PP was measured through chemical titration. The results showed that solid phase graft polymerization of MAH in PE/PP in-reactor blend granules produced graft copolymer with high amount of grafted MAH, and the amount of grafted MAH was raised slightly when St was introduced as comonomer. The graft in-reactor blend was fractionated into five fractions through temperature-gradient extraction fractionation (TGEF), and the fractions were analyzed by FTIR. The results revealed that MAH is mainly grafted on the PE segments, whereas MAH was predominantly grafted on the PP segments when St was present in the graft polymerization system. In addition, the final product is still in the form of regular spherical granules, which is beneficial for industrial processing.     

The productive scientific career of Charles Pedersen (October 3, 1904–October 26, 1989)

Charles Pedersen's career is reviewed from the time of his early life in Korea and Japan and scientific training in the United States to the present. His 42-year research career was practically and scientifically productive, leading finally to a share of the Nobel prize in chemistry for 1987. Commercially significant accomplishments included a large improvement in the yield of tetraethylead antiknock and discovery of the first oil soluble agents for inhibiting catalytic effects of copper in degradation of petroleum products and rubber. This led to a study of the interactions of metals with chelating agents and the resultant effects on oxidation reactions, thence to the behavior of peroxides and their reactions with substrates. He also discovered the antiknock activity of ferrocene. While studying the effects of ligands on the catalytic behavior of vanadium he discovered the crown compounds and their ability to include alkali metal ions. He devoted the last years of his career to elaborating their chemistry.Taken in part with permission fromCurrent Topics in Macrocyclic Chemistry in Japan, E. Kimura (ed.), Hiroshima University School of Medicine, Hiroshima, 1987.     

High‐Throughput Synthetic Chemistry Enabled by Organic Solvent Disintegrating Tablet

Synthetic chemistry remains a time‐ and labor‐intensive process of inherent hazardous nature. Our organic solvent disintegrating tablet (O‐Tab) technology has shown potential to make industrial/synthetic chemistry more efficient. As is the case with pharmaceutical tablets, our reagent‐containing O‐Tabs are mechanically strong, but disintegrate rapidly when in contact with reaction media (organic solvents). For O‐Tabs containing sensitive chemicals, they can be further coated to insulate them from air and moisture.     

人口老龄化与区域产业结构——基于分位数回归的实证研究

基于2005-2016年的省级面板数据,运用分位数回归实证分析了人口老龄化背景下,产业结构优化升级的影响因素.结果表明:全部样本的老年抚养比对产业结构优化升级的阻碍作用十分明显,东部对产业结构的影响不显著,中部的阻碍作用与全国趋势相反,西部的阻碍作用与全国趋势相同,具有明显的区域差异性;全部样本和东中西部的人均GDP都是正向推动产业结构合理化和高度化;全部样本和西部的政府行为对产业结构调整的抑制作用在增强,而东中部对产业结构调整的促进作用在增强;全部样本和东部的创新效率对产业结构调整有不断增强地推动作用,中部对产业结构调整的促进作用在减弱,而西部对产业结构调整的阻碍作用在增强.     

Extraction-Spectrophotometric Determination of Arsenic in Environmental Samples with Iodide and Amidines

Abstract

A simple and rapid method for the spectrophotometric determination of traces of total arsenic present in industrial waste waters is described. It is based on the reaction of As(III) with I^? in 5 –6 M HCl, and extraction of the iodo-arsenite complex formed into chloroform with amidines. The molar absorptivity of AsI₄ ^? with 11 different amidines is in the range (3.9 –7.9) × 10³ lmol^?1 cm^?1 at λ_max = 380 –395 nm; the simplest compound, N,N′-diphenylbenzamidine (DPBA) has been chosen for further studies. The limit of detection with DPBA is 0.1 μg As/ml. The method is highly selective with almost no interference from all anions and cations tested.     

Combination of the Particle Size Distributions of Some Industrial Minerals Measured by Andreasen Pipette and Sieving Techniques

It is known that size of the individual particles is the predominant factor affecting the behavior of particulate materials, and that the size effects become increasingly important as the particles become finer. In this article, particle size distributions (PSDs) measured by different techniques, i.e. sieving and Andreasen pipette sedimentation, were combined for different mill (ball and rod) products of some industrial (talc and quartz) minerals. The corrected sedimentation data came closer to the sieving data. The apparent mean shape factors, r, determined from the corrected PSDs for the talc mineral ground by ball and rod mill were found to be 1.34, 0.62, whereas it was 1.00, 1.12 for the quartz mineral ground by ball and rod mill, respectively. The results show that the ball milled products of talc mineral have more regular (rounder in shape) particles than those of rod milled, but the rod milled products of quartz mineral studied were not more regular in shape than ball milled products of quartz mineral as confirmed by the SEM pictures and reviewed literature.     

更新视角下的上海近郊型工业园区公共活动空间网络构建

上海近郊型工业园区正走向功能多元共生、空间集约发展、注重人文关怀的产城融合转型之道，公共活动空间面临服务对象多元化、游憩需求差异化、存量空间待激活的更新诉求。因此,提出了企业服务驿站、产业社区花园、生活休闲游园3类公共活动空间。以上海松江工业园区为对象，基于手机信令和兴趣点（POI）两类大数据分析，进行公共活动空间的增补与分类，由慢行系统联系公共活动节点，共同构建了公共活动空间网络。探索了大数据支持下的空间网络构建方法，为近郊型工业园区空间更新提供借鉴。     

A Chemical History of Polycyclic Musks

Musk odorants are ubiquitous in fine perfumery as well as household products, and are divided into four main families, the nitromusks, the macrocyclic musks, the polycyclic aromatic musks, and the alicyclic musks, following their order of appearance on the perfumery market. This article presents the scientific and industrial adventures during the discovery of the seven commercial polycyclic musks, which invigorated the aroma chemistry corporations during the second half of the 20th century, resulting in relentless competition. Research and development strategies are exposed, and reactivity, analytical, mechanistic, and structure–activity relationships aspects are discussed as well as some biographical elements of the main scientific actors, and some fine perfumery examples are given as illustrations of their use.     

Dynamic effects in inefficiency: Evidence from the Colombian banking sector

Firms face a continuous process of technological and environmental changes that requires them to make managerial decisions in a dynamic context. However, costs and constraints prevent firms from making instant adjustments towards optimal conditions and may cause inefficiency to persist in time. We propose a dynamic inefficiency specification that captures differences in the adjustment costs among firms and non-persistent effects of inefficiency heterogeneity. The model is fitted to a ten year sample of Colombian banks. The new specification improves model fit and have effects on efficiency estimations. Overall, Colombian banks present high inefficiency persistence but important differences between institutions are found. In particular, merged banks present low adjustment costs that allow them to recover rapidly efficiency losses derived from merging processes.     

Getting Ring‐Closing Metathesis off the Bench: Reaction‐Reactor Matching Transforms Metathesis Efficiency in the Assembly of Large Rings

Reported is the first study of the influence of reactor configuration on the efficiency of a challenging ring‐closing metathesis (RCM) reaction. With the intention of increasing the generality of RCM scaleup and reducing its dependence on substrate modification, macrocyclization of an unmodified, low effective‐molarity diene was explored using different reactor types, in conjunction with a commercial, homogeneous Grubbs catalyst. Optimized performance is compared for a conventional batch reactor (BR), a continuous plug‐flow reactor (PFR), and a continuous stirred‐tank reactor (CSTR). In the PFR, maximum conversion is achieved most rapidly, but product yields and selectivity are adversely affected by co‐entrapment of ethylene with the catalyst, substrate, and product in the traveling “plug”. Use of the CSTR, in which ethylene is efficiently swept out, affords an order‐of‐magnitude increase in total turnover numbers, and reduces the required catalyst loadings by 25× relative to the BR (to 0.2 mol %), while improving RCM yields and selectivity to quantitative levels. Continuous‐flow methodologies that support liberation of the ethylene co‐product thus show great promise for industrial uptake of RCM.