影响磷酸脲生成质量因素的实验研究

目前,关于磷酸脲制备工艺的报道比较含糊、数据不一,原料中杂质对磷酸脲质量的影响探讨不够深入。本文对磷酸与尿素为原料制备磷酸脲工艺中的结晶环节进行了实验研究,采用正交实验方法分析了影响磷酸脲质量的四个因素：中和温度、磷酸浓度、磷酸中硫、氟含量,并用回归分析法从宏观上建立数学模型,以预期和指导生产实际。     

羧甲基壳聚糖吸附废水中锌离子工艺的优化

研究羧甲基壳聚糖吸附废水中锌离子,通过考察羧甲基壳聚糖质量浓度、处理温度和处理时间等影响因素,以吸附率为响应指标,采用响应面法进行工艺优化.结果表明,吸附最佳工艺条件为羧甲基壳聚糖质量浓度5g·L-1、处理温度70℃和反应时间4.37h.在此优化条件下羧甲基壳聚糖对废水中锌离子的吸附率为92.45%,与模型预测值(92.30%)非常吻合.     

双核金属酞菁的制备及其对二苯并噻吩的催化氧化性能

采用微波法合成了双核酞菁钴,并采用红外光谱、紫外可见光谱、热重分析对其进行表征。以二苯并噻吩(DBT)为反应底物,考察双核酞菁钴对DBT催化氧化性能,筛选出较优催化剂,并进行脱硫反应工艺条件优化。结果表明,双核酞菁钴具有较好的催化性能,在室温下、双核酞菁钴用量为0.01 g(cat)/5 m L、空气流量为80 m L/min、反应温度为40℃、反应1 h,DBT脱硫率达到97.17%。催化剂重复使用5次,催化效果无明显下降。氧化产物经红外光谱、质谱分析为DBTO2。对芳香烃及烯烃进行了催化氧化实验,发现该工艺对油品的质量基本无影响。     

藤穿通痹胶囊的工艺及质量控制研究

采用薄层色谱法对鸡血藤、穿山龙、虎杖、干姜进行定性分析;采用高效液相色谱(HPLC)法测定藤穿通痹胶囊中虎杖苷的含量.藤穿通痹胶囊的最佳水煎工艺为第一次加13倍量水,煎煮3 h,第二次加10倍量水,煎煮2 h,线性关系良好.优选的藤穿通痹胶囊水煎工艺提取率高,可行性好,工艺稳定,同时建立的鉴别方法专属性强,定量方面简单、准确,适用于对藤穿通痹胶囊的质量控制.     

乙二醇催化氨化合成乙二胺

为了探索乙二胺绿色合成的新工艺,采用自制的负载型双组分复合金属氧化物Ni O/Cu O/Al2O3为催化剂,对乙二醇进行催化氨化制备乙二胺,用气相色谱法对反应物进行分析检测,采用X射线衍射仪(XRD)、X射线光电子能谱分析仪(XPS)等技术手段对催化剂结构进行了表征。通过考察催化剂组成、物料比、温度和时间等因素对反应的影响,确定了合成乙二胺的最佳工艺条件:催化剂活性组分n(Ni)∶n(Cu)=3∶1、催化剂加入量3%、氨醇质量比4∶1、反应温度180℃、反应压力0.6 MPa、反应时间4 h,乙二胺的选择性达56.7%,乙二醇转化率达68.6%。与传统的二氯乙烷法相比较,本工艺更清洁友好。     

APS引发制备高分子量PDMDAAC

以已知杂质种类和含量的一步法工业二甲基二烯丙基氯化铵(DMDAAC)单体水溶液为原料,用过硫酸铵(APS)为引发剂,采取低温一次性加入引发剂,分阶段升温方式进行聚合反应,通过合成工艺的优化方法,得到了最高特性黏数值为3.17 dL/g的聚二甲基二烯丙基氯化铵(PDMDAAC),单体转化率为94.8%,采用NMR、IR光谱测试技术对产物进行了结构表征。分别考察了DMDAAC质量分数为57.5%~70.0%、APS与DMDAAC质量比为0.15∶100~0.40∶100、Na4EDTA与DMDAAC质量比为0~0.014 2∶100、聚合反应引发温度T1在40~50℃、聚合反应熟化温度T3在50~90℃范围内的以上5个因素对产物特性黏数和单体转化率的影响规律。结果表明,DMDAAC质量分数为65.0%、APS与DMDAAC质量比为0.35∶100、Na4EDTA与DMDAAC质量比为0.007 1∶100、T1为46℃、T2为50℃,T3为70℃,各反应3 h为最佳工艺条件。     

改性胺微胶囊固化剂制备工艺的优化与性能

以改性胺1618固化剂为囊芯、脲醛树脂为壁材单体,采用界面聚合技术,成功制备了一种新型聚脲改性胺微胶囊固化剂。通过正交设计试验,考察了芯壁质量比、乳化剂种类和质量分数及搅拌速率对微胶囊包覆率、粒径大小及分布情况的影响,并确定了最佳制备工艺条件。采用马尔文激光粒度仪、扫描电镜对微胶囊粒径大小、分布情况及表面形貌进行表征,采用热重分析仪及傅里叶变换红外光谱对其化学结构进行表征,通过拉伸试验对自修复材料的断裂力学性能进行研究。结果表明,该微胶囊含有固化剂芯材,其热稳定温度为198°C,当芯壁质量比为0.7∶1、乳化剂为阿拉伯胶、乳化剂质量分数为1.5%、搅拌速率为800r/min时,所制备的微胶囊包覆率达到79.8%,平均粒径为207.5nm,呈规则的球形,分散性及表面致密性好。当基体材料中加入质量分数为1%的微胶囊后,拉伸强度提高64%,弹性模量提高287%。     

硫代硫酸钠制备实验的改进

以亚硫酸钠与硫粉为原料制备硫代硫酸钠,反应在碘量瓶中进行,控制反应温度为103~104℃,反应液保持在20~25mL,剧烈沸腾的状态下反应30min,产品收率及质量分数分别大于86%和99%。该工艺具有反应装置简单、反应时间短、反应条件容易控制、产品收率及质量分数较高等优点;以重铬酸钾为基准物,采用间接碘法测定了产品的质量分数,经测定回收率及做对照试验证明,该方法准确度高。     

大型循环流化床锅炉与煤粉炉汞排放特性研究

选取600 MW循环流化床锅炉及1000 MW煤粉炉的电厂进行汞迁移转化及排放特性研究,采用EPA 30B法对烟气汞质量浓度进行采样,同时采集了入炉煤、飞灰、底渣、石灰石、工艺水、脱硫石膏、脱硫废水等固体液体样品进行对比分析.研究了两电厂现有污染物控制装置对汞的协同脱除作用,分析了汞的迁移转化规律.两电厂烟气经过污染物...     

液态奶加工过程中反映工艺条件标志物的研究进展

随着我国乳制品人均消费量的逐年增长，乳制品进口贸易量也与日俱增，因此对进口乳制品的质量控制具有重要意义。调查发现，进口超高温瞬时灭菌（UHT）奶（俗称常温奶）的糠氨酸含量显著高于国产UHT奶，存在加热过度、添加复原乳的问题。虽然目前无法对进口乳制品企业进行源头和加工工艺的监管，但可在乳制品热处理工艺控制领域中采用监测乳品中某种反映工艺条件的标志物来控制乳品的质量，其中糠氨酸就是乳制品加工过程中反映工艺条件的标志物。该文简述了目前国内外对乳制品加工过程中9种标志物的研究概况，以期能为完善我国乳制品加工过程中的监管制度提供理论依据，保障消费者权益。     

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%.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.