聚乙烯基吡啶树脂吸附乳酸的研究

在35℃下,实验测定了乳酸在聚乙烯基吡啶上的吸附等温线,测定了乳酸水溶液在以聚乙烯基吡啶为吸附剂的固定床吸附柱中的穿透曲线,研究了乳酸浓度、进口流速及柱高对穿透曲线的影响。用Freundlich模型关联了吸附等温线,用线性推动力模型描述吸附柱的动态过程并从实验穿透曲线回归得到了总传质系数,模型计算值与实验数据符合良好。     

三磷酸胞苷在Duolite A-30树脂上的交换过程研究

根据CTP在离子交换树脂上的吸附容量和分离因数的大小,确定Duolite A-30树脂适合CTP与CDP,CMP之间的分离.对CTP在Duolite A-30树脂上的吸附动力学和热力学研究表明,在283.15K~303.15K之间,CTP的质量浓度在7.5g/L以上时,Duolite A-30树脂对CTP的吸附主要受颗粒扩散的控制,其有效扩散系数为D=3.47×10-7cm2/s,溶液的质量浓度≤1.0g/L时,CTP与Duolite A-30树脂之间的交换速率主要受液膜控制,其液膜扩散系数为Kf =4.112×10-4/s.同时测定了不同条件下三磷酸胞苷溶液在Duolite A-30树脂固定床离子交换柱中的穿透曲线,研究了进口浓度、进口流速、原料液温度、原料液的pH值及柱高对穿透曲线的影响.用二阶动力学推动力模型描述固定床动态过程,考察了轴向返混对穿透曲线的影响,并从穿透曲线回归得到总传质系数,模型计算值与实验数据符合良好.     

固相络合萃取脱除柴油中碱性氮化物的工艺及模型研究

应用自行合成的分离材料对固相络合萃取脱除柴油中碱性氮化合物进行了研究。测定了不同条件下柴油在合成树脂柱中的穿透曲线和洗脱曲线,实验测得动态吸附容量达到了7.85mg/gwetresin,碱性氮的脱除率达到了91%。表明本法具有树脂吸附容量大,碱性氮或收率高的特点;同时利用二阶动力学推动力模型描述固定床动态过程,考察了轴向返混对穿透曲线的影响,模型计算值与实验数据符合较好。     

D001树脂吸附铁离子穿透曲线的平衡级模型建立与验证

对D001树脂吸附含酸废水中铁离子的过程进行了研究。对其吸附等温方程进行拟合,同时,建立平衡级模型对动态吸附小试和扩大实验的穿透曲线进行拟合和预测。结果表明,D001树脂吸附铁离子的过程符合Langmuir等温吸附模型;在固定床吸附小试及扩大实验中,平衡级模型对D001树脂动态吸附铁离子的穿透曲线均能较好地拟合,该模型将传质速率方程从穿透曲线中分离出来;通过平衡级模型计算得到,在泄漏控制点较低时,固定床的理论级数对透过液量的影响较大。     

用固定床和搅拌槽进行吸附（离子交换）柠檬酸的特性研究

用固定床和搅拌槽进行了吸附(离子交换)柠檬酸实验。研究固定床工艺和搅拌槽工艺对吸附剂吸附效率和工作吸附容量的影响,比较了逆流解吸和顺流解吸对回收率的影响。在装填大孔吸附剂的固定床上用逆流解吸获得96％的回收率。在搅拌槽中,吸附剂的吸附效率大于固定床中吸附剂的吸附效率,建立了柠檬酸吸附动力学模型,获得理论计算值与实验值一致的结果。     

浸渍活性炭脱除低质量浓度H2S性能的研究

浸渍法制备了Na2CO3浸渍活性炭（IACⅠ）和一种高效脱硫剂（IACⅡ）。通过测定低质量浓度H2S在固定床上的穿透曲线，比较了原活性炭（AC）、IACⅠ和IACⅡ的脱硫效果。考察了原料气相对湿度，H2S质量浓度对穿透过程的影响。建立了固定床反应器一维轴向扩散模型模拟脱硫穿透曲线，并进行了数值求解。通过模型计算与实验测量穿透曲线拟合，确定了有效扩散系数等参数。结果表明，IACⅡ的脱硫效果最佳，其有效扩散系数较IACⅠ有所提高。提高相对湿度有利于增大硫容，但有效扩散系数略有降低。随着H2S入口质量浓度升高，有效扩散系数增大，穿透变快，硫容略有降低。     

金属有机骨架材料MOF-5上噻吩硫化物的吸附分离

将金属有机骨架材料应用于燃油深度脱硫研究。采用水热法合成了金属有机骨架材料MOF-5,利用XRD、N2吸附和SEM等技术对其结构进行了表征。通过测定固定床吸附穿透曲线,考察了模型燃油类型对MOF-5吸附分离噻吩效果的影响。结果表明,MOF-5对硫化物的吸附容量超过了文献报道;在脂肪油中其穿透容量和饱和容量质量分数分别为0.90%和1.92%,在芳香模型物质中其穿透容量和饱和容量质量分数分别为0.64%和1.72%。通过采用与活性炭分层填装吸附柱技术,解决了溶解水对脱硫的影响,为吸附脱硫技术提供了新思路。     

基于BP神经网络研究儿茶素在ADS-8树脂固定床的吸附过程

以信阳毛尖茶叶浸提液为原料,研究儿茶素在ADS-8树脂固定床的吸附过程及优化吸附条件。试验基于BP神经网络建立吸附模型,通过仿真分析上样浓度、柱径比和流速对穿透时间、穿透体积的影响。模型的模拟值与试验值的相关系数为0.992,模拟值与试验值没有显著差异。最佳工艺条件为上样浓度1.5mg/mL,柱径比17:1,流速3.0mL/min。建立的模型可用于模拟儿茶素在ADS-8树脂固定床的吸附过程,结果为吸附树脂法制备儿茶素提供一定的参考。     

麦壳对水溶液中铜离子的动态吸附研究

对麦壳柱吸附铜离子的动态实验进行了研究。pH为5时有利于吸附,Na+和Ca2+的存在不利于吸附,说明在吸附过程中存在离子交换机理。溶液流速、溶液浓度对流出曲线有较大的影响。吸附后的麦壳用0.5mol/L盐酸再生,能重复使用。对不同流速和不同浓度的流出曲线用Thomas和Yoon-Nelson线性模型进行了拟合,并预测了流出曲线。结果表明,饱和吸附量随着初始浓度的增大而增大,随流速的增加而减小;穿透时间随初始浓度和流速的增大均减小。在不同条件下的线性相关系数为0.920～0.948,说明Thomas和Yoon-Nelson模型都可用于描述穿透曲线。     

超高交联树脂吸附二氯甲烷蒸气的平衡和动力学特性及应用

开展了超高交联吸附树脂对气体中二氯甲烷的静态吸附行为研究,分别采用Langmuir、Freundlich和Dubinin-Astakov模型方程对吸附平衡数据进行拟合分析,拟合结果表明,Dubinin-Astakov方程能较好地拟合吸附平衡数据,表明在吸附过程中微孔填充起着很重要的作用;采用固定床吸附工艺研究了二氯甲烷在树脂上的动态吸附行为,用Yoon-Nelson模型对穿透曲线进行拟合,实验数据与模拟值吻合良好。在实验研究的基础上开发了二氯甲烷废气超高交联树脂吸附回收工艺并建立工业化装置,处理效果良好、运行稳定。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.