A Study on Stoichiometry of Complexes of Tributyl Phosphate and Methyl Isobutyl Ketone with Lithium in the Presence of FeCl_3

To study the characteristic of liquid-liquid extraction equilibrium of lithium from brine sources, the complexes formed from tributyl phosphate （TBP） and methyl isobutyl ketone （MIBK） with lithium were investi- gated using FeCl3 as coextracting agent. Liquid-liquid extraction reaction mechanisms were proposed and the stoichiometry of tetrachloroferrate（III） complex with lithium was obtained by regressing the experimental data. It is found that the stoichiometry of tetrachloroferrate（III） to lithium in the complex is 1 ： 1 with either TBP or MIBK as extractant in kerosene. The stoichiometry of the complex of TBP with Li was 1 ： 1 and that of MIBK with Li was 2 ： 1. The formed complexes of TBP and MIBK with lithium are determined to be LiFeCla-TBP and LiFeC14.2MIBK, respectively, according to the rule of neutralization.

Facile purification and immobilization of organophosphorus hydrolase on protein-inorganic hybrid phosphate nanosheets

Oriented immobilization of enzymes helps to maintain their native structure and proper orientation for high-performance engineering to meet extensive biocatalysis demands.However,the supporting materials used for orientated immobilization are usually costly or complicated in preparation,affecting their practical applications.In this work,a facile purification and immobilization method was proposed for enzyme immobilization based on organic-inorganic hybrid calcium phosphate nanocrystal(Ca Ps)induced by Cu^(2+) modified bovine serum albumin(BSA-Cu).Then,the as-prepared hybrid calcium phosphate nanosheet,BSA-Cu@Ca Ps,was utilized for one-pot purification and immobilization of His-tagged organophosphorus hydrolase(OPH)by metal-affinity binding to the incorporated BSA.BSA-Cu@Ca PsOPH exhibited enhanced p H stability and thermal stability compared to the free enzyme.Moreover,BSA-Cu@Ca Ps-OPH could retain more than 75%and 56%of initial activity after reuse 5 and 10 times,respectively.The results demonstrated that this facile strategy was promising for the effective biodegradation of organophosphorus pesticides with the immobilized enzyme.

Vapour-phase O-methylation of Catechol with Methanol on Ti-containing Phosphate Catalysts

Ti-containing phosphate（ Ti-P-O ） catalysts with different molar ratios of P to Ti （0--2. 0 ） were synthesized and characterized by XRD, N2-adsorption/desorption, IR and temperature-programmed desorption （TPD） methods. The catalytic properties of Ti-P-O samples in the vapor-phase O-methylation of catechol with methanol were also studied. The catechol conversion increases with the increase of the molar ratio of P to Ti in a range of 0-0. 33, while a further increase in the P content leads to a decrease of the catalytic activity. Meanwhile, the selectivities of the catalysts to the main product（guaiacol） increase gradually with the increase of the molar ratio of P to Ti. The presence of relatively strong Lewis acidic and/or basic sites in the P-free catalyst should be responsible for the formation of C-alkylation products. The weak acid-base characteristics of the catalysts are favourable for the mono-O-methylation of catechol. In comparison with the Lewis acidic sites, the Bronsted acidic sites on the catalysts are more active for the title reaction.

POLYMERIZATION OF ETHYLENE METHYL PHOSPHATE IN THE PRESENCE OF SODIUM POLY(ETHYLENE GLYCOL)ATE

Poly(ethylene methyl phosphate)-poly(ethylene glycol)-poly(ethylene methyl phosphate) triblock copolymers carrying hydroxyl group at both chain ends were synthesized with sodium poly(ethylene glycol)ate as initiator. The effects of the factors such as solvent, amount of the initiator and reaction time were investigated. The copolymers were characterized by IR, H-1-NMR, H-1{P-31}-NMR, C-13-NMR, P-31{H-1}-NMR, and DSC. High molecular weight of the copolymer and high yield of the polymerization were achieved within 3 min at 25 degrees C. The polymerization process was studied by P-31{H-1}-NMR and transesterification was found during longer polymerization time.

Built-up Effect of Core Material for Microencapsulated Flame Retardant Containing Dimethyl Methyl Phosphate

The flame retardants containing organophosphorus compounds have extensively been used in the flame retarding of polymer materials. Among others, dimethyl methyl phosphate (DMMP) was applied in flame retarding of polyurethane owing to its so much merit. However, the water-soluble property of DMMP restricted its application in textile fabric. The flame retarding system containing DMMP will be microencapsulated to form a novel flame retardant that could be used in textiles. We have studied the built–up effect of DMMP with some inorganic compounds to improve the afterflame and afterglow suppression in the flame retarding system. The experimental data indicated that inorganic compounds containing various non-metal elements P, N, B and metal ions Mg2+, Al3+, Ca2+, Zn2+, Cu2+, Mn4+ could be applied in flame retarding systems as additives to effectively suppress afterflame or afterglow.

Modified RNA with a Phosphate-Methylated Backbone. A Serious Omission in Our (Retracted) Study at HIV-1 RNA Loops and Integrated DNA. Specific Properties of the (Modified) RNA and DNA Dimers

After the recent publication in the Journal of Biophysical Chemistry entitled “Retracted HIV Study Provides New Information about the Status of the in Vitro Inhibition of DNA Replication by Back-bone Methylation”, it is of importance to review the results of Buck’s group on the synthesis and conformation analyses of phosphate-methylated RNAs in order to afford information on the absence of a further investigation with regard to this de facto acceptable approach. In fact these compounds belong to the very first group of RNAs with a modified neutral backbone by phosphatemethylation. In contrast to the corresponding phosphate-methylated DNAs with a frozen B-conformation, the phosphate-methylated RNAs show an A-conformation. The latter is a prerequisite for duplex formation with (complementary) (natural) RNA. A number of experiments support this fundamental statement. After the HIV study was retracted, the overall results concerning the phosphate-methylated RNAs were published without mentioning Buck’s initial proof of concept and his contributions. Generally, the (modified) dimer RNAs and DNAs possess a number of specific biophysical properties. A novel explanation is given for conflicting structural determinations.

Phosphate-Methylated Oligonucleotides Past, Present and Future

At the moment, we see a great interest for application of Anti Sense Oligonucleotides (ASOs) in order to regulate the expression of genes related to certain diseases. These nucleotides obtained a number of fascinating properties by means of chemical manipulation of natural DNA and RNA under conservation of Watson-Crick base-pairing. About 35 years ago for our research in this field, we selected synthetically (short) phosphate-methylated DNA and RNA. It was concluded that there is an exclusive selection in hybridization affinity with natural DNA and RNA. These (bio)chemical and physical-chemical properties are extensively published. ASOs have found their way in public health as is clearly shown in the treatment of (progressive) neurological diseases. We focus specifically on the past, present and future of the phosphate-methylated oligonucleotides, illustrated with different research studies in chemistry and biophysics. A new field of application of modified DNAs is based on interactive improvements of sensitivity and specificity of nanowire field effect transistor gene chip by designing phosphate-methylated DNA as probe.

Elimination of Cationic and Anionic Dyes by Natural Phosphate

The present work aims to study the adsorption, determining the ability of phosphate to remove cationic dyes, MB （methylene blue） and CV （crystal violet） and an anionic dye, the MO （methyl orange）. To explain the important reduction of pollution parameters obtained from its use as a filter bed. Natural phosphate is contacted with an aqueous solution having a concentration of 20 mg/L for 90, 45 and 20 min respectively for the MB, CV and MO. Experimental results show that the phosphate totally eliminates the CV and the WB. While, the adsorption of MO is very low. The Langmuir isotherm applies to MB and MO while the adsorption of CV uses the Freundlich isotherm.

磷酸三丁酯、4-甲基-2戊酮对铝锂溶液中锂的萃取行为

以磷酸三丁酯(TBP)作为主要萃取剂,4-甲基2-戊酮(MIBK)作为协助萃取剂,三氯化铁(FeCl3)作为共萃剂,以铝锂溶液体系作为试验对象,全面系统的研究了萃取剂的各组成成分、水相溶液的pH值、铁锂原子比、萃取相比、萃取时间以及静置时间对铝锂溶液中锂的萃取效果的影响。通过正交试验确定了萃取反应的最佳反应参数:萃取相比为5∶2,铁锂原子比为2∶1,pH值为1.5,TBP体积分数为70%,MIBK体积分数为15%,萃取时间为10 min。在此条件下,锂的单级萃取率可达82%,锂铝单级分离因数可达51。对萃取分离过程的反应机理进行了研究,深入探索了铁锂共萃取效应,确定了反应产生的萃合物形态为LiFeCl4·2TBP·MIBK,并探究了萃合物形成过程中的键合方式。该萃取方法经济高效,适用于铝锂溶液中锂的分离。

介孔磷酸锡催化1,3-二羟基丙酮制备乳酸甲酯

以三嵌段聚合物P123为结构导向剂在水热条件下制备了介孔磷酸锡(SnPO),采用XRD、N2物理吸附、TEM、FT-IR、Raman、XPS和Py-IR对SnPO结构和酸性进行了表征并关联其催化1,3-二羟基丙酮(DHA)制备乳酸甲酯的性能.结果表明:500℃焙烧后的SnPO为层状介孔材料,含有丰富的Lewis(L)酸位点,能够在温和条件下催化DHA制备乳酸甲酯.该反应遵循平行-序列的反应路径,需要Br?nsted(B)酸和L酸的协同参与,且相对高的L∶B值有助于提高乳酸甲酯选择性.此外,SnPO具有足够的结构稳定性,有机物在其表面沉积而导致的失活可以通过500℃空气焙烧进行再生.

簇或舱级释放全氟己酮对磷酸铁锂电池的灭火效果

储能电站中灭火系统的有效性越来越受到重视,但全氟己酮局部和空间布置方式对灭火有效性的影响缺乏研究。以磷酸铁锂电池模组为试验对象,搭建舱级试验平台,采用1 C充电倍率对电池模组过充至热失控进而着火,并实施无灭火措施、全氟己酮灭火剂局部释放和舱级释放以对火灾进行抑制。分析气体及温度数据,对比簇级和舱级释放下全氟己酮对磷酸锂铁电池模组火灾的抑制效果并提出高效的灭火剂释放策略。结果显示:簇级释放4 s内扑灭明火,降温速率达1.37℃/s;舱级释放46 s内扑灭明火,降温速率为0.81℃/s;簇级灭火速率比舱级灭火速率快且2者均能防止复燃。采取簇级和舱级释放相结合的灭火方式具备最佳火灾抑制效果。

Arginine methylation of ribose-5-phosphate isomerase A senses glucose to promote human colorectal cancer cell survival

Cancer cells remodel their metabolic network to adapt to variable nutrient availability. Pentose phosphate pathway(PPP) plays protective and biosynthetic roles by oxidizing glucose to generate reducing power and ribose. How cancer cells modulate PPP activity in response to glucose supply remains unclear. Here we show that ribose-5-phosphate isomerase A(RPIA), an enzyme in PPP, directly interacts with co-activator associated arginine methyltransferase 1(CARM1) and is methylated at arginine 42(R42). R42 methylation up-regulates the catalytic activity of RPIA. Furthermore, glucose deprivation strengthens the binding of CARM1 with RPIA to induce R42 hypermethylation. Insufficient glucose supply links to RPIA hypermethylation at R42, which increases oxidative PPP flux. RPIA methylation supports ROS clearance by enhancing NADPH production and fuels nucleic acid synthesis by increasing ribose supply. Importantly, RPIA methylation at R42 significantly potentiates colorectal cancer cell survival under glucose starvation. Collectively, RPIA methylation connects glucose availability to nucleotide synthesis and redox homeostasis.

磷酸西格列汀中间体的合成工艺改进

研究以1,2,4-三氟苯作为起始原料制备得到磷酸西格列汀的中间体4-(2,4,5-三氟苯基)-3-氧丁酸甲酯。结果表明,氯甲基化反应中,当1,2,4-三氟苯与多聚甲醛、浓硫酸、氯化钠及相转移催化剂的摩尔比为1∶2.5∶4∶3∶0.05,60℃反应5h可达最高收率85.2%;格氏反应中,当选用2-甲基四氢呋喃(2-MeTHF)为格氏试剂制备的溶剂,1,2,4-三氟苯与镁的摩尔比1∶5,在低温下制备格氏试剂后持续通入4h二氧化碳气体,最高收率可达88.6%;缩合反应及脱羧反应中,2,4,5-三氟苯乙酸在二环己基碳二亚胺及4-二甲氨基吡啶的作用下与麦氏酸缩合反应后在甲醇溶液中脱羧,缩合反应摩尔比为1∶1.2∶1.2∶1.2,脱羧温度为65℃时可达最高收率86%。3步反应总收率达64.9%。产物结构经NMR及熔点等数据确证。

醚菌酯的气相色谱分析方法

介绍了醚菌酯原药样品的气相色谱定量分析方法 ,选用HP - 5石英毛细管柱 ,以磷酸三苯酯为内标物 ,进样口和检测器温度均为 2 5 0℃ ,柱温为 2 30℃ ,对醚菌酯原药进行测定。该方法的变异系数为 0 14 9,回收率为 98 12 %～ 10 1 4 5 % ,线性相关系数r =1 0 0 0。

茉莉酸甲酯对雨生红球藻虾青素含量和dxs基因表达的影响

雨生红球藻是一种能产生重要次生代谢产物———虾青素的单细胞绿藻,茉莉酸甲酯(MeJA)等诱导因子可促进植物次生代谢产物的积累。以雨生红球藻为研究对象,研究了不同浓度MeJA对雨生红球藻细胞生长、虾青素含量和dxs基因表达的影响。结果表明,MeJA在抑制雨生红球藻细胞生长和总虾青素产量的积累的同时,却能促进雨生红球藻单位细胞虾青素的合成能力。当MeJA浓度为800μmol/L时,单位细胞虾青素合成能力可达1.75×10-9mg,相比对照组(1.42×10-9 mg)增加23.24%。RT-PCR分析结果表明,dxs基因的表达受MeJA的诱导,800μmol/L MeJA处理条件下,dxs基因的表达水平最高。相关分析结果表明,MeJA作用下的雨生红球藻虾青素含量和dxs基因表达量呈正相关,推断dxs基因可能是雨生红球藻虾青素合成的一个关键酶基因,这为进一步通过代谢工程策略提高雨生红球藻虾青素含量提供了一个靶点,也为虾青素规模化生产和探讨虾青素积累的分子机理提供参考。

共沉淀法制备Ag_3PO_4/MWCNTs复合光催化材料及其表征与降解染料废水

通过简单的共沉淀法制备掺杂不同碳管含量的Ag_3PO_4/MWCNTs复合光催化材料,并对样品进行XRD、SEM、FT-IR、UV-vis等表征。以300 W氙灯模拟太阳光,通过光催化材料对甲基橙的降解来评价光催化材料对印染废水的催化效果。结果表明:PVP的存在使得制备的Ag_3PO_4颗粒表面光滑、结晶性好、尺寸较小(200~300 nm);经过混酸改性后增加了大量的带有羧基基团的碳管,均匀地分布在Ag_3PO_4颗粒表面,与其形成了很好的复合;合成的复合材料较纯Ag_3PO_4具有更加优异的光催化活性,当碳管质量分数为3.6%时催化效果最好。最后,对所制备材料的光催化机理进行了分析。

笼状双环磷酸酯甲基醚的合成

以季戊四醇作为起始原料经四步反应合成了一种未见报道的化合物──笼 状双环磷酸酯甲基醚．

磷酸三丁酯与三烷基胺类萃取剂对锌离子的协同萃取

研究了磷酸三丁酯（TBP，B）和三烷基胺萃取剂（N235，R，N，R=C8～C10）在HCl介质中对Zn^2＋的萃取，该混合体系对Zn^2＋存在明显的协同效应，协萃系数为12．34。用斜率法和恒摩尔法探讨了萃取机理，确定了萃合物的组成为（R3N）15·ZnCl2．B，协萃反应方程式：ZnCl2（n）＋1．5R3N（o）＋B（o）-（R3N）1.5·ZnCl2·B（o）。计算了该反应的平衡常数和热力学函数△H、△G和△S，证明反应为放热过程。比较了TBP-N235的混合体系萃取Zn^2＋和Cd^2＋的性能，并考察了TBP与另一种胺类萃取剂N,N′-二（1．甲庚基）乙酰胺（N503）的混合体系对Zn^2＋和Cd^2＋的萃取。结果表明：TBP-N235的混合体系对Cd^2＋没有明显的协同效应；TBP-N503的混合体系对Zn^2＋和Cd^2＋协同效应都不明显。计算了TBP-N235的混合体系对Zn^2＋和Cd^2＋的分离系数，证明此体系可以从富镉溶液中分离锌。

对甲氧基肉桂酸甲酯的一锅式绿色合成

以茴香醛(1)和丙二酸二乙酯(2)为原料,L-脯氨酸/磷酸钠为催化剂,甲醇为溶剂,经Knoenenagel缩合反应一锅式合成了对甲氧基肉桂酸甲酯。较适宜的反应条件为:141.5 mmol,n(1)∶n(2)∶n(L-脯氨酸)=1.0∶1.3∶0.3,n(L-脯氨酸)∶n(磷酸钠)=6∶1,甲醇100 mL,回流反应6 h,收率达70.2%。

新型含氮磷酸酯添加剂的合成及摩擦学性能研究

以脂肪酸甲酯为原料合成一种新型含氮磷酸酯添加剂,通过红外对其结构进行表征,采用四球摩擦试验机考察其在不同基础油中的摩擦学性能,并用扫描电子显微镜和能谱仪观察分析磨痕表面的形貌及元素分布。结果表明:含氮磷酸酯添加剂具有良好的热分解性能和极压抗磨性能;实验后在钢球表面发现了磷元素,表明在摩擦过程中,含氮磷酸酯添加剂通过化学反应在摩擦表面生成了磷酸铁等化合物,从而起到了极压抗磨的作用。