含硅有机锡化合物在酯化反应中的催化性能研究

考察了含硅有机锡化合物在酯化反应中的催化活性,并以合成乙酸异戊酯的反应为例,探讨了影响反应的各种因素。其中,三[(三甲基硅基)亚甲基]氯化锡的催化活性最高,在催化剂用量1.5%,反应时间5h条件下,酯化率达到93.7%。     

Quantum DCS系统及其应用体会

中国联合水泥公司3000t／d熟料生产线电气控制系统采用了法国施耐德公司的Quantum DCS系统，实现对全厂所有设备的工艺操作和控制。全面介绍了QuantumDCS系统的特点、功能系统构成网络，并详细总结了确保该系统稳定可靠运行的使用和维护的经验。     

朗盛:助力涂料行业客户提升竞争力——朗盛携高品质颜料和杀菌剂亮相2007中国国际涂料展

朗盛,作为全球领先的特殊化学品企业,每年以不同的形象亮相于中国国际涂料展。2007年,朗盛以一系列用于涂料行业的高品质颜料和杀菌剂亮相,以期助力中国涂料行业客户提升竞争力。期间,本刊特对朗盛无机颜料业务部亚太区负责人韩乐福博士及材料保护品大中华区负责人顾其峰就朗盛产品及市场方面进行了专访。     

A Simple D 2-Sampling Based PTAS for k-Means and Other Clustering Problems

Given a set of points \(P \subset\mathbb{R}^{d}\) , the k-means clustering problem is to find a set of k centers \(C = \{ c_{1},\ldots,c_{k}\}, c_{i} \in\mathbb{R}^{d}\) , such that the objective function ∑ _x∈P e(x,C)², where e(x,C) denotes the Euclidean distance between x and the closest center in C, is minimized. This is one of the most prominent objective functions that has been studied with respect to clustering. D ²-sampling (Arthur and Vassilvitskii, Proceedings of the Eighteenth Annual ACM-SIAM Symposium on Discrete Algorithms, SODA’07, pp. 1027–1035, SIAM, Philadelphia, 2007) is a simple non-uniform sampling technique for choosing points from a set of points. It works as follows: given a set of points \(P \subset\mathbb{R}^{d}\) , the first point is chosen uniformly at random from P. Subsequently, a point from P is chosen as the next sample with probability proportional to the square of the distance of this point to the nearest previously sampled point. D ²-sampling has been shown to have nice properties with respect to the k-means clustering problem. Arthur and Vassilvitskii (Proceedings of the Eighteenth Annual ACM-SIAM Symposium on Discrete Algorithms, SODA’07, pp. 1027–1035, SIAM, Philadelphia, 2007) show that k points chosen as centers from P using D ²-sampling give an O(logk) approximation in expectation. Ailon et al. (NIPS, pp. 10–18, 2009) and Aggarwal et al. (Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques, pp. 15–28, Springer, Berlin, 2009) extended results of Arthur and Vassilvitskii (Proceedings of the Eighteenth Annual ACM-SIAM Symposium on Discrete Algorithms, SODA’07, pp. 1027–1035, SIAM, Philadelphia, 2007) to show that O(k) points chosen as centers using D ²-sampling give an O(1) approximation to the k-means objective function with high probability. In this paper, we further demonstrate the power of D ²-sampling by giving a simple randomized (1+?)-approximation algorithm that uses the D ²-sampling in its core.     

P450酶启发的染料后修饰铁卟啉MOF光催化氧化

受细胞色素P450酶氧化代谢的启发,将染料酸性红87（Acid Red 87）后修饰到金属有机框架PCN-222(Fe)中,构筑非均相拟酶光催化剂Acid Red 87@PCN-222(Fe),拉近染料与铁卟啉中心的距离,利用光致电子转移模拟P450的电子传递链。以1-(4-甲氧基苯基)乙醇为模板底物,对光催化氧化的条件如溶剂、电子牺牲剂、氧源等进行筛选,得到优化反应条件为高碘酸钠(53.5 mg, 0.25 mmol),2,6-二甲基吡啶三氟甲磺酸盐(64.3 mg, 0.25 mmol),Acid Red 87@PCN-222(Fe)(12.0 mg, 0.00625 mmol),乙腈(2 mL),530 nm波长LED光照反应24 h。催化剂重复使用3次后仍保持活性和晶态结构。该催化体系对苄基碳氢键氧化具有良好的底物适用范围,可应用于非甾体类抗炎药匹美诺芬的区位选择性氧化，产率为48%，该体系还可将芳基硫醚类化合物氧化至相应的亚砜，体现其在精细化工制药、工业脱硫领域的应用潜质。     

汽油清净分散剂聚异丁烯胺合成过程研究

用高活性聚异丁烯为原料,通过双氧水氧化制备环氧聚异丁烯,然后用乙二胺胺解得到目的产物。实验研究确定了最佳的制备工艺:环氧化温度80~85℃、反应时间5~6 h;胺解温度130~150℃,反应时间6~8 h。测定了胺解反应宏观动力学方程,在乙二胺大量过量的情况下为一级连串反应,rp=k1CPIBO-k2CPIBA;k1=10.077exp(-14 192.6/RT);k2=0.888 7exp(-985 2.7/RT)。通过红外图谱对合成过程进行监控。通过车架实验测试了目的产物清净分散性,结果表明已经达到了国外同类产品的要求。     

新法合成磷酸锌锂及其多重数据挖掘

对合成磷酸锌锂的新方法进行了研究.以磷酸锌铵和碳酸锂为原料经室温固相反应得到前驱体,接着让这一前驱体在高温下保温晶化得结晶形态的磷酸锌锂.基于均匀设计试验方案以及数据挖掘技术的应用,研究了研磨时间、保温时间、保温温度对磷酸锌锂晶体合成的影响.XRD表征的结果表明,用最佳工艺条件合成得到的产物为63 nm的LiZnPO4,且产物产率高达99.5%.实验成功地同时优化控制了磷酸锌锂的组成及产率,从而得到比较纯净的、结晶态的磷酸锌锂晶体.     

乙腈法萃取精馏丁二烯过程模拟与工艺优化Ⅱ.乙腈质量分数、腈烃比和回流比对分离效果的影响

采用Unifac基团结构法在乙腈法萃取精馏丁二烯装置中建立了乙腈-C4系统相平衡关系,利用PROⅡ化工模拟软件对第一萃取精馏塔、第二萃取精馏塔内乙腈质量分数、腈烃比、回流比等工艺条件对分离效果的影响进行了系统分析。结果表明,第一萃取精馏塔适宜的工艺条件为:乙腈质量分数93%~94%,腈烃比7·0~8·0,回流比2·5~3·0;第二萃取精馏塔适宜的工艺条件为:乙腈质量分数93%~94%,腈烃比1·5~2·0,回流比3·0。     

Chemical interactions between soil N and alkaline-hydrolysing N fertilizers

Chemical interactions between soil N and alkaline-hydrolysing N fertilizers labelled with¹⁵N were studied in the laboratory using twelve-irradiated soils. Fertilizer was recovered in the soil organic N fraction via the process of NH₃ fixation. NH₃ fixation at day 7 varied from 1.8 to 4.6% of the N added as aqua ammonia at 1000 mg kg^–1 soil. The amount of NH₃ fixed increased with increasing rates of application of NH_3(aq) and urea. The rate of NH₃ fixation decreased with time, with more than 55% of the total NH₃ fixation in 28 days occurring in the first week following application of 2000 mg urea-N kg^–1 soil. Soil pH and NH₃ fixation varied in response to N source, and increased in the order of di-ammonium phosphate 3 fixation, resulting in the release of unlabelled ammonium (deamination) and a real added nitrogen interaction in all but two of the soils studied. The release of NH ₄ ⁺ initially increased up to a pH of 7.5, was inhibited between pH 8.5 and 9.0, but increased thereafter. The balance (N_bal) between NH₃ fixation and deamination was either positive or negative, depending on the pH of the fertilized soil, which was directly related to N source and concentration for a given soil.