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化学专业英文文献

有效的销售车辆 当一位抵押银行家将发现革新和可信的方法岁月把重要的概念对Over讲清的你的这把钥匙, Seroka & 同事有效使用多种销售车辆帮助抵押交织有机金属 结构关于一定期 最小表面有 特别大的毛孔 Banglin陈,1 M Eddaoudi,1 S T海德,2 M O '基夫,3 O M Yaghi1 * Interpenetration(catenation)早就被在稳定和多孔的晶体结构的成就方面认为为一种主要的妨碍。 非常多孔和结构上稳定的网络的设计的一个策略利用metalorganic 可以被在一个三重定期的最小P的几何学表面上装配产生是准确认为交织的更贯通的结构的组成部分。 我们使用4,49,40苯1,3,5 triyl-tribenzoic酸(H3BTB), 铜(II)硝酸盐, 以及N, 准备Cu3(BTB)2(H2O)3z的N9-dimethylformamide(DMF)(DMF)9(H2O)2(MOF-14), 其结构显示被相互加强的一对交织的有机金属的结构。 那些结构包含非常大毛孔,4埃在内直径,在方面哪个大量 气体和有机溶剂的数量可能可逆是sorbed。 连锁,或者catenation,在分子上 水平已经捕获科学家的想象 因为为建造的它的潜能 复杂的生物学和合成组件。 很多有机的(1,2)和DNA(3,4)catenanes 由于连结的macrocyclic 分子现在已经被描述。 第一个例子 连结的蛋白质中,戒指最近被报告 在HK97噬菌体的capsid里; 在这里 材料,72枚戒指被连锁形成A 用一种被比作"链子的方式关闭表面 邮件"(5)。 有贯通的定期结构 网(1,6)也catenated在方面 一张网的连接通过的感觉 另一个的戒指,反之亦然。 这 结构的特征被广泛地相信有A 对尺寸和可接近的负的影响 在多微孔的材料(7)里的毛孔。 这里, 我们鉴定一类型净价在哪个顶点 落在上一定期最小表面,和为 interpenetration更恰当的 考虑交织,以便结构 形成一个无限的定期锁子甲。 作为A 这个设计原则的样品,我们描述 综合,结构和sorption 一种多孔的有机金属的结构的特性 (MOF)有任何的最大的毛孔 这样的一种化合物的稳定的事件报告 到目前为止

要有足够的英语阅读理解能力和词汇量,要熟悉化学专业的一些基本知识和化学工艺过程

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不知道,随便给你一个疏水缔合型聚合物P(AMTA)溶液性质的研究疏水缔合型水溶性聚合物是指在聚合物亲水性大分子链上带有少量疏水基团的一类水溶性聚合物。在聚合物水溶液中,疏水基团之间由于憎水作用而发生聚集,使大分子链产生分子内和分子间缔合。在临界缔合质量分数以上,形成分子间缔合为主的超分子结构,增大了流体力学体积,故具有较好的增黏性。在盐溶液中,由于小分子电解质的加入增加了溶液极性,使疏水缔合作用增强,表现出明显的抗盐性质。 疏水缔合型水溶性高分子很难合成,且不易表征,把疏水部分连接到水溶性聚合物链上,一般采用胶束共聚合或者使用具有表面活性的大单体进行共聚,胶束聚合需要在体系中加入大量的表面活性剂,这就增加了后处理过程的复杂性。利用表面大单体共聚合,需要事先合成大单体,这方面的技术也有相当大的难度。作者采用丙烯酸十四酯作为疏水单体,直接用沉淀聚合法制备疏水缔合型聚合物P(AM/TA)共聚物,从而使共聚反应及其产物的后处理过程较为简单易行。并用凯达尔定氮法表征共聚物的组成,研究共聚物的溶液性能和对苯丙乳液的增稠性。 1实验 1.1试剂 丙烯酰胺(AM),质量分数不少于985%,根据文献提供的方法提纯;N,N-甲基甲酰胺(DMF),分析纯;甲醇、氯化钠,化学纯;丙烯酸十四酯(TA),实验室自制;苯丙乳液由福建省福州树脂有限公司提供。 1.2P(AM/TA)共聚物的合成 称取一定量的AM和TA单体,用DMF溶解,转入三颈瓶中,通氮除氧。升温至80℃,加入引发剂反应4h,过滤,产物用甲醇洗涤多次,以除去未反应的单体。40℃真空干燥至恒重。 1.3分析测试 凯达尔定氮法测定共聚物的组成。用乌氏黏度计测定共聚物溶液特性黏度[η],测试温度为(30±O1)℃。聚合物溶液表观黏度用NDJ-I型旋转黏度计测定。 2结果与讨论 2.1共聚物稀溶液性质不同疏水基团摩尔分数的P(AM/TA)共聚物在蒸馏水和w(NaCl)=5%的溶液中的特性黏度[η]值列于表1。 聚合物的[η]正比于溶液中大分子线团的流体力学体积,因而能反应大分子线团收敛、卷曲的程度。从表1可知,随共聚物的TA链节摩尔分数的增加,其水溶液的[η]值逐渐减小,在w(NaCl)=5%的溶液中也是持续减小。这是因为在稀溶液中,疏水基团缔合以分子内缔合为主,随着TA摩尔分数的增加,分子内缔合增强,导致分子链卷曲。在盐溶液中,由于离子电荷的作用,使疏水链节分子内缔合力增强,分子链收缩,因而[η]值也持续下降。 2.2疏水基团TA摩尔分数对聚合物溶液黏度的影响 图1和图2分别表示P(AM/TA)系列共聚物及PAM在蒸馏水和w(NaCl)=5%的溶液中表观黏度与聚合物质量分数的关系曲线。PAM溶液黏度随其质量分数的增加而平缓上升,而疏水共聚物溶液的质量分数为3O%~4O%时其黏度急剧增加,表明疏水基团聚集而导致分子间缔合,形成了物理交联网络。此时共聚物溶液的质量分数即是临界缔合的质量分数。如图1所示,随TA摩尔分数增加,共聚物溶液的黏度显著增加。当疏水基团摩尔分数较高时,其溶液黏度随质量分数增加的速度更快,共聚物的临界缔合质量分数降低。如图2所示,加入Nacl溶液后,溶液表观黏度有较大提高,如质量分数为O%的P(AM/TA)-1 5聚合物溶液在20℃,转速为6r/min时,黏度达OmPs,而在水溶液中的黏度只有374mPa·s。不同TA摩尔分数的聚合物的质量分数均较其在纯水中低。Hydrophobically associating polymer P (AMTA) the nature of the study solution Hydrophobically associating water-soluble polymer is the hydrophilic polymer with a small amount of macromolecular chain hydrophobic group of a class of water-soluble Aqueous solution in the polymer, the hydrophobic groups and between the role as a result of hydrophobic aggregation occurred, so that large molecules have a molecular chain and inter-molecular Associating the critical mass fraction of the above, the formation of intermolecular association based supramolecular structure, increases the volume of fluid mechanics, it has good by In salt solution, because of the addition of small molecule electrolyte solution increased polarity, so that co-operation with enhanced hydrophobic association, shows that the nature of the Hydrophobically associating water-soluble polymer-based synthesis is difficult and not easily characterized, in part to hydrophobic chains connected to the water-soluble polymer, the general use of micellar copolymerization, or the use of the large surfactant monomer to copolymerization, polymer micelles need in the system by adding a large number of surface-active agent, which, after an increase of the complexity of the The use of the surface monomer copolymerization, the need for prior synthesis of large monomer, this technology also has considerable Author tetradecyl acrylate used as a hydrophobic monomer, the direct use of precipitation polymerization Preparation of hydrophobically associating polymer P (AM / TA) copolymers, so that the product of copolymerization and post-processing is more simple and easy And characterization of nitrogen determination Kedar copolymer composition, study the solution properties of copolymers of styrene-acrylic emulsion and of the 1 Experimental 1 Reagents Acrylamide (AM), the mass fraction of not less than 985 percent, according to documents provided by purification methods; N, N-dimethylformamide (DMF),分析纯; methanol, sodium chloride, chemical pure; acrylic 10 four acetate (TA), laboratory-made; styrene-acrylic emulsion resin from Fuzhou in Fujian Province L 2P (AM / TA) Copolymer Check that a certain amount of monomer AM and TA, using DMF dissolved into three-neck bottle, pass oxygen Warming to 80 ℃, reaction by adding initiator 4h, filtering, washing the product several times with methanol to remove unreacted 40 ℃ vacuum drying to constant 3 Analysis and Testing Determination of nitrogen Kedar will be the composition of Determination of intrinsic viscosity with copolymer solution viscosity [η], the test temperature (30 ± O1) ℃ Apparent viscosity of polymer solution with NDJ-I-type rotary viscometer 2 Results and Discussion 1 Dilute Solution Properties of Copolymers of different mole fraction of hydrophobic groups of the P (AM / TA) copolymers in distilled water, and w (NaCl) = 5% of the solution intrinsic viscosity [η] values listed in Table Polymer [η] is proportional to the solution of the fluid dynamics of macromolecular coil volume, which can respond to the convergence coil macromolecules, the degree of We can see from Table 1, with the copolymer chain of the TA increase in mole fraction, the aqueous solution of [η] value decreases in w (NaCl) = 5% of the solution is continued to This is because in dilute solution, the hydrophobic group to intramolecular association based association, with the mole fraction of the increase in TA, to enhance intramolecular association, resulting in the molecular chain In salt solution, because of the role of ionic charge, so that intramolecular hydrophobic chain to enter into force enhancement, molecular chain contraction, so [η] value continued to TA hydrophobic group 2 mole fraction of polymer solution viscosity on the impact of figures 1 and 2, respectively, P (AM / TA) series of copolymers and PAM in distilled water, and w (NaCl) = 5% in the apparent viscosity of the solution and the relationship between the mass fraction of polymer PAM solution viscosity with the increase of mass fraction of gentle rise, and the hydrophobic copolymer solution for the mass fraction of 3O% ~ 4O%, when a sharp increase in viscosity, indicating that aggregation of hydrophobic groups and lead to intermolecular association, forming a physical crosslinking网络 At this point the mass fraction of copolymer solution that is the critical mass fraction of the As shown in Figure 1, with the mole fraction of TA increased, the viscosity of copolymer solution increased When the mole fraction of hydrophobic groups is high, the solution viscosity increases with the mass fraction of the faster, the critical aggregation copolymer mass fraction As shown in Figure 2, by adding Nacl solution, the solution has greatly enhanced apparent viscosity, such as the mass fraction of O% for the P (AM / TA) -1 5 polymer solution at 20 ℃, rotation speed 6r/min , the viscosity of OmPs, and viscosity in aqueous solution only 374mPa TA different mole fraction of the mass fraction of polymer in water were

要有足够的英语阅读理解能力和词汇量,要熟悉化学专业的一些基本知识和化学工艺过程

化工专业英文文献

翻译后:合成丙二醇甲醚超过胺改性多孔二氧化硅超声技术学张甲,乙,温榆河张甲,乙,平利,赵宁,魏伟,孙予罕, * 一个国家重点实验室,煤转化研究所,煤化学,中国科学院,太原030001 ,中国b研究生院,中国科学院,北京100039 ,中国收到2006年5月16日接见了在修订的表格2006年7月10日;接受, 2006年7月12日网上提供2006年7月21日摘要胺改性多孔二氧化硅合成了超声波技术温和条件下。样本中,其中的特点由打赌, 29 Si核磁共振光谱,元素分析和指标吸附染料,展示了光明的催化性能,对合成丙二醇甲醚由甲醇和环氧丙烷。他们都高良品率和可重用性反应,这表明超声波技术是有效的为编写有机改性二氧化硅催化剂。此外,可能的反应机制提出了合成丙二醇甲醚对这种类型的催化剂。 2006年Elsevier公司乙诉,保留所有权利。 关键词:改性多孔硅;超声波技术;环氧丙烷;甲醇;丙二醇甲醚1 。导言试图把heterogenize均相催化剂替代更传统的试剂和催化剂得到的一个领域的研究,看到了越来越大的兴趣。 许多近期的工作重点是编制有机固体基地,以heterogenize均相胺类催化剂。改造过程中普遍经营搅拌,加热,回流等[ 1-3 ] 。 最近,有兴趣的合成声化学反应成长[ 4 ] 。超声波技术已被广泛适用于两相系统由于其自身的优势,如由于精度高,速度快。大多数的这些反应都涉及非均相化学相互作用[ 5 ] 。在面积多孔材料官能化有机群体, 然而,只有有限的应用超声已探索[ 6,7 ] 。在目前的工作,另一种合成航线,形成胺改性炭黑开发用超声波能量,能产生化学修改对固体汽蚀现象[ 8 ] 。 该胺改性二氧化硅''单网站''基地实力分别有前途的催化剂为各种各样的反应[ 9 ] 。 合成乙二醇醚超过基准催化剂是一个重要的一种反应,在有机合成中。有几种方法合成丙二醇甲醚[ 10,11 ] 。其中环氧丙烷的方法大多是方便和工业可行的。一般来说,丙烯氧化反应脂肪醇经酸或基地的催化作用。 用催化剂,在这个过程中,包括先前同质基地或酸(氢氧化钠,酒类钠和三氟化硼) ,后来固体酸和基地。然而,很少有研究报道使用胺改性氧化硅为催化剂合成丙二醇甲醚,虽然无机坚实基础催化剂表现良好的活性,在反应。该固定氨基酸职能上孔支持,而这是与''单网站''基地实力,可负担不起实现这种反应。 在当前的工作中,胺官能二氧化硅催化剂包括nh2/sio2 ,中NH ( Ⅱ ) 2nh2/sio2 , tapm / 二氧化硅( 2,4,6 - triaminopyrimidine /二氧化硅)和tbd/sio2 ( 1,5,7 - triazabicyclo [ 4,4,0 ] dec-5-ene/sio2 ) ,准备3 -氨丙基三甲氧基硅烷( aptms ) , N -二[ 3 -(三methoxysilyl )丙基]乙二胺( edptms )和3个- chloropropyltrimethoxysilane ( cptms )作为耦合代理商,由超声波技术在温和的实验条件。在同一时间,以证实优点超声波技术, nh2/sio2还编写了传统的方法,以了解有效行为超声波技术在编写功能化多孔二氧化硅。此外,催化活性有机固体碱催化剂的评价由合成丙二醇甲醚从甲醇和环氧丙烷。此外,尽可能反应机理,提出了为合成丙烯乙二醇甲醚对这种类型的催化剂。 2 。实验1 。合成催化材料该胺官能二氧化硅催化剂,可取得了两方面的类似条件下,作为报早些时候[ 7 ] 。 aminopropylsilyl官能二氧化硅编写如下: 0克二氧化硅预热为12小时,在473 K的真空,以消除所有吸附水分,但地表哦小组,并比冷却下来,以室温在真空和转入250毫升三角烧瓶。 混合后,与0毫升环己烷和0毫升aptms ,混合在三角烧瓶投入超声波浴2小时( sheshin ,日本,经营权60瓦特) 在常温下。该催化剂,然后得到了提取与甲苯在索氏提取器近一个时期以来24 h和干燥,在333 K的真空。同样的方法已用于编制中NH ( Ⅱ ) 2nh2/sio2 。 tbd/sio2编写了两个步骤:二氧化硅是第一改性3 - chloropropyltrimethoxysilane途经同一法,因为这对aminopropylsilyl官能二氧化硅和chloropropylsilyl官能二氧化硅当时反应与tbd ( 0 g )在环己烷( 0毫升) 。由此治理后,由超声波振动1每小时随后, 催化剂,获得了提取与甲苯在索氏提取器近一个时期以来, 24小时和干燥333 K的真空。同样的方法已用于编制对tapm/sio2 。 2 。表征内容的碳,氮和氢在所有样品的测定用vario下午分析器。该比表面积,总孔容和平均孔隙直径测量N2吸附-解吸方法一micromeritics ASAP的2000文书(的Norcross 加文) 。表面地区进行了计算打赌方法,以及孔径分布得到运用bjh孔隙分析,以氮气吸附- 脱附等温线。 29 Si核磁共振谱录就bruker平均海面- 400分光计。该基地的实力样品检测哈米特指标。 3 。催化试验催化性能测试在75毫升一批反应堆与摩尔比的甲醇和环氧丙烷正在5:1 。运行后,在403 K的10小时下磁悲壮,反应堆冷却下来到室温。 该产品,然后再过滤和分析,由气相色谱仪与火焰离子化检测后,离心脱离催化剂。催化剂洗涤溶剂,并用于回收试验。 3 。结果与讨论1 。改性多孔二氧化硅与胺群体内容的碳,氮和氢无胺多孔硅和所有改性样品进行了元素分析。 wtorg 。和Norg 。 % 获得由n % , c %和H % (见表1 ) 。结果这有没有碳和氮在无胺多孔二氧化硅。因此,碳和氮在改性样品中,必须从有机硅烷。 元素分析表明, Norg的。 %的嫁接有机群体达到常规方法称为从文献[ 12 ] 13 mmol / g上升,这是迄今为止低于该样本编制的超声波技术( 00 mmol / g上升) (见表1 ) 。这应该是由于应用超声波能量,以固体和液体, 可提供变化,包括汽蚀(气泡形成,在一个流动性)和化学反应(加速度化学反应) ,等等[ 13 ] 。作为一个结果,过程包括颗粒大小修饰,清洗表面或形成新鲜[ 14,15 ] ,可获得了在非均匀介质中,在固液界面。 至于把有机改性的多孔硅,汽蚀现象所带来的超声波能加快液体转移速度在孔多孔材料与液固界面。因此,采用液体有机硅烷可以很好地接触silanol群体对内壁的多孔二氧化硅反应与他们在很短的时间,搅拌,而不能达到这种效果。 因此,改造过程中完成了简单迅速超声。 在29 Si核磁共振光谱在固体状态表示共价键之间形成silylant代理人和silanol 集团对二氧化硅表面(见图1 ) 。两个共振在109和99 ppm的原因可能是29 Si原子核四泗O型硅联系(第四季)和29 Si原子核经三泗O型硅的联系和一个哦(第三季) [ 16 ] ,分别为。 该共振,在58和67 ppm的被分配以RSI公司( OSI )以( OH ) 2和的RSI ( OSI )以3 ,分别为[ 17 ] ,其中说明成功的有机官能团的多孔二氧化硅有机群体通过共价键。的C / N 值(摩尔比) ,也可以在一定程度上反映嫁接反应silanol群体和有机硅烷[ 18 ] 。 nh2/sio2 ,中NH ( Ⅱ ) 2nh2/sio2和tbd/sio2显示的C / N = 3-5 , 5-0和3月3日至3月6日,分别。该结果,同时也表明锚碇胺群体四O型硅债券。这个同意的结果,该29sinmr谱。 2 。结构和碱度的样本图。二显示器N2吸附等温线为样本研究。该官能样品展示IV型等温线具有明确的滞后环与毛细管冷凝水气。这表明,在材料仍孔之前和之后官能和改性各种有机硅烷难以改变等温式。比表面积和孔容表明逐渐减少为易。 %嫁接有机群体的增加(见表2 ) 。这可能是归功于在场的功能群。一部分氨基接枝微孔,也引发了一场跌幅在比表面积。效果有机集团对孔径的样品为轻度样本nh2/sio2和NH ( Ⅱ ) 2nh2/sio2 。但正如为样本tbd/sio2和tapm /二氧化硅,也许是因为以大框架内( Ⅱ ) 3/tapm和( Ⅱ ) 3 / tbd群体,其平均孔径的样本下降到90和82 nm左右。然而,平均孔隙直径为没有减少,严重由于低Norg的。 % 值的样本。 该基地强度H类固体表面定义为有能力的表面转换成一种吸附电中性酸纳入其共轭基地。当一个电中性酸指标是吸附了坚实的基础,从非极性溶液,色条酸指标是改变现在说的,其共轭基地,只要扎实拥有必要的基础力量,传授电子对向酸[ 19 ] 。了坚实的一大正面有个HH 强大的基本地盘。嫁接不同功能组别可能会导致不同的基本优势。如表3 , tbd/sio2有最高碱强度的H 0 , 而nh2/sio2和NH ( Ⅱ ) 2nh2/sio2不仅有碱度的H 3和3 < h < 0 ,分别。 其它城市相比,改性样品, tapm/sio2 曾最弱碱度的H < 2 。因此,基本实力该样本是在常规的tbd / 二氧化硅>中NH ( Ⅱ ) 2nh2/sio2 > nh2/sio2 > tapm/sio2 。 3 。催化性能催化活性测试,在合成丙烯乙二醇甲醚由甲醇和丙烯氧化氮(见表3 ) 。如表3所示,宝转换和同分异构体的选择性(比例为1 -甲氧基-2 -丙醇/ 总丙二醇甲醚)达到3和3 % ,但无提交催化剂,分别。其中催化剂,无胺多孔二氧化硅显示低催化活性由于弱酸强度的表面silanol群体。为锚定氨基酸组中NH ( Ⅱ ) 2nh2/sio2和nh2/sio2催化剂被发现以更积极和选择性比其他催化剂,以1 - 甲氧基-2 -丙醇后, 10小时的反应。 tapm/sio2 催化剂低环氧丙烷转化率( 0 % ) 该异构体的选择性为6 % 。 tbd/sio2 , 中NH ( Ⅱ ) 2nh2/sio2和nh2/sio2催化剂都显示高环氧丙烷转化率( " > 94 % ) ,但不同的异构体异构体选择性。中NH ( Ⅱ ) 2nh2/sio2和nh2/sio2与弱基强度较高,同分异构体的选择性( " > 82 % ) ,而tbd/sio2中度基地实力表明较低的异构体选择性( 7 % ) 。至于奠定了坚实的基础催化剂,催化剂与温和的基地实力应具有良好的异构体选择性[ 20 ] 。较低的异构体的选择性对tbd/sio2可能是由于大范围内tbd 。 该催化剂易于回收过滤,并受到利用7个周期不断转换环氧丙烷> 89 %和综合利用许多回收难以改变异构体选择性下403的K (见表4 ) ,说明胺集团嫁接到二氧化硅的表面稳定,在实验条件下。 可重用的其他样品类似这对nh2/sio2 。 4 。可能的机制无机固体碱催化剂已广泛使用为合成丙二醇甲醚从甲醇和环氧丙烷[ 31 ] ,其中,甲醇离子和质子吸收,对酸和基本地盘对催化剂的表面,分别,然后甲醇离子攻击的C ( 1 )的位置。在本案件中,但是, 该样本用于该反应的特点单一网站,即该催化剂具有独特的场址基本相似向同质基地。因为没有刘易斯酸性网站上的催化剂,该机制应有所不同从那些涉及双功能催化剂。收益机理1 -甲氧基-2 -丙醇形成nh2/sio2体现在计划1 。还有的H -债券形成以甲醇及胺组在道路in路径2 ,因为该阻甲基蒲, 氧原子在甲醇攻击的C ( 1 )的位置和质子被吸收就基本地盘的催化剂,然后( 1 )邻带侦破,然后拿起质子以表1 -甲氧基-2 -丙醇。 似乎可以合理地认为,较高的活性中NH ( Ⅱ ) 2nh2/sio2 , nh2/sio2和tbd/sio2是由于合适的基地实力,而不能只形成氢键,而且裂缝的,它很容易。 tapm/sio2与十分薄弱,基础实力,只能形成更多的不稳定氢键。因此,活性tapm/sio2低于其他样本。条件是这种机制合理的,大框架内的有机群体,大概可能会影响攻击的立场与氧原子在甲醇。因此, tbd的大框架内,导致较低的异构体的选择性。因此,既恰当基地实力和简单的框架的有机群体对于高转化率和选择性好,以1 -甲氧基-2 -丙醇。 4 。结论结果提交以上可以得出以下结论: ( 1 )高效率的超声波技术可以成功准备胺官能多孔二氧化硅催化剂, ( 2 )表征表示胺团体接枝二氧化硅表面共价债券, ( 3 )适当的基础实力和简单框架的有机群体重要的是转化率高选择性好,以1 -甲氧基-2 -丙醇, ( 4 ) 催化剂可以回收过滤和遭受以综合利用为许多个周期不断的活动。

Synthesis of propylene glycol methyl ether over amine modifiedporous silica by ultrasonic techniqueXuehong Zhang a,b, Wenyu Zhang a,b, Junping Li a, Ning Zhao a, Wei Wei a, Yuhan Sun a,*a State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Chinab Graduate School of the Chinese Academy of Sciences, Beijing 100039, ChinaReceived 16 May 2006; received in revised form 10 July 2006; accepted 12 July 2006Available online 21 July 2006AbstractAmine modified porous silica were synthesized by ultrasonic technique under mild The samples, which were characterizedby BET, 29Si NMR spectra, element analysis and indicator dye adsorption, exhibited promising catalytic properties towards the synthesisof propylene glycol methyl ether from methanol and propylene They had both high yields and reusability in the reaction, indicatingthat ultrasonic technique was effective for the preparation of organically modified silica Furthermore, the possible reactionmechanism was proposed for the synthesis of propylene glycol methyl ether over such type of 2006 Elsevier BV All rights Keywords: Modified porous silica; Ultrasonic technique; Propylene oxide; Methanol; Propylene glycol methyl IntroductionThe attempt to heterogenize homogeneous catalyst asalternatives to more traditional reagents and catalysts hasbeen one area of research that has seen increasing Much recent work was focused on the preparation oforganically modified solid bases to heterogenize homogeneousamine The modification process was generallyoperated by stirring, heating, refluxing, [1–3]Recently, the interest in synthetic sonochemistry reactionshas grown [4] The ultrasonic technique has been widelyapplied in two-phase systems due to its advantages, suchas high accuracy and Most of these reactions haveinvolved a heterogeneous chemical interaction [5] In thearea of porous materials functionalized by organic groups,however, only limited applications of ultrasound have beenexplored [6,7] In the present work, an alternative syntheticroute for the formation of amine modified silica was developedby using ultrasonic energy, which can produce chemicalmodifications on solids by cavitation phenomenon [8]The amines modified silica with ‘‘single site’’ base strengthwere promising catalysts for a variety of reactions [9]The synthesis of glycol ether over base catalysts is animportant kind of reaction in organic There areseveral methods for the synthesis of propylene glycol ether[10,11] Among them the propylene oxide method is mostlyconvenient and industrial Generally, propyleneoxide reacts with fatty alcohol via acid or base The catalysts used in this process include earlier homogenousbase or acid (NaOH, alcoholic sodium and BF3), latersolid acid and However, few studies have reported theuse of amine modified silica as catalysts for the synthesis ofpropylene glycol methyl ether, though inorganic solid basiccatalysts have performed good activity in the Theimmobilization of the amino functions on a mesoporoussupport, which were with ‘‘single site’’ base strength, couldafford an achieving this kind of In the present work, amine functionalized silica catalysts,including NH2/SiO2, NH(CH2)2NH2/SiO2, TAPM/SiO2 (2,4,6-triaminopyrimidine/SiO2) and TBD/SiO2(1,5,7-triazabicyclo[4,4,0]dec-5-ene/SiO2), were preparedwith 3-aminopropyltrimethoxysilane (APTMS), N-[3-(tri-methoxysilyl)propyl]ethylenediamine (EDPTMS) and 3-chloropropyltrimethoxysilane (CPTMS) as the couplingagents by ultrasonic technique under mild At the same time, in order to confirm the meritsof ultrasonic technique, NH2/SiO2 was also prepared bythe conventional method in order to understand the effectivebehaviour of ultrasonic technique in the preparationof functionalized porous In addition, the catalyticactivity of the organic solid base catalysts was evaluatedby the synthesis of propylene glycol methyl ether frommethanol and propylene Furthermore, the possiblereaction mechanism was proposed for the synthesis of propyleneglycol methyl ether over such type of E Synthesis of catalytic materialsThe amine functionalized silica catalysts could beachieved in two ways under similar conditions as reportedearlier [7]Aminopropylsilyl-functionalized SiO2 was prepared asfollows: 0 g SiO2 was preheated for 12 h at 473 K invacuum to remove all adsorbed moisture but surfaceOH-groups, and than cooled down to room temperaturein vacuum and transferred into a 250 mL conical After mixed with 0 mL cyclohexane and 0 mLAPTMS, the mixture in conical flask was put into the ultrasonicbath for 2 h (Sheshin, Japan, operating power 60 W)at ambient The catalyst was then obtained byextracting with toluene in a soxhlet extractor over a periodof 24 h and drying at 333 K in The same methodwas used for the preparation of NH(CH2)2NH2/SiOTBD/SiO2 was prepared by two steps: silica was firstlymodified by 3-chloropropyltrimethoxysilane via the samemethod as that of aminopropylsilyl-functionalized SiO2,and chloropropylsilyl-functionalized SiO2 was then reactedwith TBD (0 g) in cyclohexane (0 mL) The resultantwas treated by ultrasonic vibration for 1 Afterwards,the catalyst was obtained by extracting with toluene in aSoxhlet extractor over a period of 24 h and drying at333 K in The same method was used for the preparationof TAPM/SiO CharacterizationThe content of carbon, nitrogen, and hydrogen in all thesamples was determined using a Vario EL Thespecific surface area, total pore volume and average porediameter were measured by N2 adsorption–desorptionmethod on a Micromeritics ASAP-2000 instrument (Norcross,GA) The surface areas were calculated by BETmethod, and the pore size distribution was obtained byapplying the BJH pore analysis to the nitrogen adsorption–desorption 29Si NMR spectra were recordedon a Bruker MSL-400 The base strength ofsamples was detected by hammett Catalytic testThe catalytic properties were measured in a 75 ml batchreactor with mol ratio of methanol and propylene oxidebeing 5: After running at 403 K for 10 h under magneticstirring, the reactor was cooled down to room The product was then filtered and analyzed by a gas chromatographwith a flame ionization detector after centrifugalseparation from the The catalysts werewashed with solvent and used for recycling Results and Modification of porous silica with amine groupsThe content of carbon, nitrogen, and hydrogen inamine-free porous silica and all the modified samples werecarried out by elemental W and N% wereobtained from N%, C% and H% (see Table 1) The resultsshowed that there were no carbon and nitrogen in theamine-free porous As a result, carbon and nitrogenin modified samples ought to be from the The element analysis showed that N% of the graftedorganic groups achieved by conventional methods knownfrom the literature [12] was 13 mmol/g, which was farlower than that of the sample prepared by ultrasonic technique(00 mmol/g) (see Table 1) This should be due tothe application of ultrasonic energy to solids and liquids,which could provide the changes including cavitation(bubble formation in a liquid) and chemical reaction (accelerationof chemical reaction), [13] As a result, processesincluding particle size modification, cleaning ofsurfaces or the formation of fresh ones [14,15] could beobtained in heterogeneous media at a solid liquid As to the organic modification of porous silica, cavitationphenomena brought by ultrasound could speed up theliquid transferring velocity in the hole of porous materialsand the liquid–solid As a result, the liquidorganosilanes could be well contacted with silanol groupson the inner wall of the porous silica to react with themin a short time, while stiring could not reach such Therefore, the modification process finished simply andspeedily by The 29Si NMR spectra in solid state indicated that thecovalent bond formed between silylant agents and silanolgroups on the silica surface (see F 1) Two resonancesat 109 and 99 ppm could be attributed to 29Si nucleihaving four Si–O–Si linkages (Q4) and 29Si nuclei havingthree Si–O–Si linkages and one OH (Q3) [16], The resonances at 58 and 67 ppm were assignedto RSi(OSi)(OH)2 and RSi(OSi)3, respectively [17], whichillustrated the successful organo functionalization of poroussilica by the organic groups via covalent C/Nvalue (molar ratio) could also reflect the degree of graftingreaction between silanol groups and organosilanes [18]NH2/SiO2, NH(CH2)2NH2/SiO2 and TBD/SiO2 showedthe C/N = 3–5, 5–0 and 3–6, Theresults also suggested the anchorage of amine groups bySi–O–Si This agreed with the result of the 29SiNMR Structure and basicity of samplesF 2 displays N2 adsorption isotherms for the The functionalized samples displayed type IV isothermswith clear hysteresis loops associated with This indicated that the materials remainedmesoporous before and after functionalization and themodification by various organosilanes hardly changed theisotherm The BET surface area and pore volumeshowed a gradual reduction as the N% of graftedorganic groups increased (see Table 2) This could beattributed to the presence of functional A part ofamino groups grafted onto the microporous also led to adecrease in the BET surface The effect of the organicgroups on the pore diameter of the samples was slight forthe samples NH2/SiO2 and NH(CH2)2NH2/SiO But asfor the sample TBD/SiO2 and TAPM/ SiO2, perhaps dueto the big framework of (CH2)3/TAPM and (CH2)3/TBD groups, the average pore diameters of the samplesdecreased to 90 and 82 However, the average porediameter was not decreased seriously due to the low N%values of the The base strength H of a solid surface is defined as theability of the surface to convert an adsorbed electricallyneutral acid into its conjugate When an electricallyneutral acid indicator is adsorbed on a solid base from anonpolar solution, the color of the acid indicator is changedto that of its conjugate base, provided that the solidhas the necessary base strength to impart electron pairsto the acid [19] A solid with a large positive HH hasstrong basic Grafting with different functional groupscould result in different base As shown in Table3, TBD/SiO2 had the highest base strength of H 0,while NH2/SiO2 and NH(CH2)2NH2/SiO2 only had thebasicity of H 3 and 3 < H < 0, Compared to the other modified samples, TAPM/SiO2had weakest basicity of H < Thus, the basic strengthof the samples was in the order of TBD/SiO2 > NH(CH2)2NH2/SiO2 > NH2/SiO2 > TAPM/SiO Catalytic performanceThe catalytic activity was tested in the synthesis of propyleneglycol methyl ether from methanol and propyleneoxide (see Table 3) As shown in Table 3, PO conversionand isomer selectivity (the ratio of 1-methoxy-2-propanol/total propylene glycol methyl ether) reached 3 3% without the presented catalysts, Amongthe catalysts, the amine-free porous silica showed the lowcatalytic activity due to the weak acid strength of the surfacesilanol For anchored amino groupsNH(CH2)2NH2/SiO2 and NH2/SiO2 catalysts were foundto be more active and selective than other catalysts to 1-methoxy-2-propanol after 10 h of TAPM/SiO2catalyst had low propylene oxide conversion (0%) withthe isomer selectivity of 6% TBD/SiO2,NH(CH2)2NH2/SiO2 and NH2/SiO2 catalysts all showedhigh propylene oxide conversion (>94%), but different NH(CH2)2NH2/SiO2 and NH2/SiO2 withweaker base strength had higher isomer selectivity(>82%), while TBD/SiO2 with moderate base strengthshowed lower isomer selectivity (7%) As for solid basecatalysts, catalysts with moderate base strength shouldhave good isomer selectivity [20] The lower isomer selectivityof TBD/SiO2 could be due to the big framework ofTBDThe catalysts were easily recovered by filtration, andsubjected to utilization for seven cycles with constant conversionof propylene oxide >89% and the utilization formany recycles hardly changed the isomer selectivity under403 K (see Table 4), indicating that amine groups graftedonto silica surface were stable under the experimental The reusability of other samples was similar to thatof NH2/SiO Possible mechanismInorganic solid base catalysts have been extensively usedfor the synthesis of propylene glycol methyl ether frommethanol and propylene oxide [31], in which, the methoxideion and proton was absorbed on acidic and basic siteson the catalyst surface, respectively, and then the methoxideion attacked the C(1) In the present case, however,the samples used for the reaction were characteristicof single site, , the catalyst with unique basic site similarto the homogeneous Because there was no Lewisacidic site on the catalysts, the mechanism should be differentfrom those involving bifunctional The plausiblemechanism of 1-methoxy-2-propanol formation onNH2/SiO2 is illustrated in Scheme There was H-bondsformation between methanol and amine groups in path In path 2, because of the sterically hindered CH3 of PO, theO atom in methanol attacked the C(1) position and protonwas absorbed on the basic sites of the catalysts, and thenC(1)–O band cracked, followed by pick up the proton toform 1-methoxy-2-It seems reasonable to consider that the higher activityof NH(CH2)2NH2/SiO2, NH2/SiO2 and TBD/SiO2 wasdue to the appropriate base strength, which could not onlyform H-bond but also crack it TAPM/SiO2 withvery weak base strength could only form more unstableH- Thus, the activity of TAPM/SiO2 was lower thanthe other On condition that such mechanism isreasonable, the big framework of the organic groups probablycould affect the attacking position of the O atom As a result, TBD of the big framework led tolower isomer Thus, both appropriate basestrength and simple framework of the organic groups wereimportant for the high conversion and good selectivity to1-methoxy-2- ConclusionsThe results presented above led to the following conclusions:(1) the efficient ultrasonic technique could successfullyprepare the amine functionalized porous silicacatalysts, (2) the characterization indicated that the aminegroups were grafted onto the silica surface by covalentbond, (3) appropriate base strength and simple frameworkof the organic groups were important for the high conversionand good selectivity to 1-methoxy-2-propanol, (4) thecatalysts could be recovered by filtration and were subjectedto utilization for many cycles with constant

你这个是专业论文,有很多专业词汇的。不是这个专业的很难搞。你自己用翻译软件辅助一下,应该不难啊,并且对自己也是个锻炼啊。实在不行的话,发给我看看。

一个存在已久改善渗透皮肤的医药传送的方法便是使用穿透加强剂(也称为吸收促进剂或促进剂)使剂渗入皮肤并可反转地降低边界障碍的抵抗力。有许多混合物的穿透加强功能已经过试验,包括sulphoxides(例如dimethylsulphoxide, DMSO), axones (例如 laurocapram), pyrrolidones (例如 2-pyrrolidone, 2P),醇,alkanols (乙醇,或decanol),glycols (如propylene glocol, PG, 一个经常使用的以外用服法的辅药),surfactants (也以外用为多),和terpenes。许多皮肤穿透加强剂可用的地位与实行方式已被发现了;在细胞之间的脂质matrix中的促进剂可能会扰乱细胞衬垫的基调,在细胞内的角素区域内或在当作细胞薄膜渗透体的溶剂使用加强医药分割组织。更多潜在的功能途径,如让加强剂对corneocytes中间的desmosomal连接有效验或更改皮肤中的新陈代谢,或影响运送药物物体的的热力活动/可溶性都是可能实行的,也都在此评论中一一探讨。

化学专业英文文献翻译

相反的,ZTRS荧光反应金属离子 在水溶液中,Zn2 100% CH3CN +和Cd2 +结果 blue-shifted排放量最大的波长变化 从481到430、分别为432纳米构成资讯, S4数据,利用S5);然而,加上Zn2 +和Cd2 + ZTRS 100% DMSO对red-shifted排放造成的 最大的波长变化,从472 512 532海里。 支持信息、数据分别S6、S7)。这个 图1。对影响ZTRS荧光在乙腈/水,v / v(50:50)。激发波长:360海里。[ZTRS 10μM])。(一)pH 7-8。插图:从荧光强度作为函数在483纳米的pH值;(2)pH 7-8。插图:从比率荧光成函数变化。 图2。(一)。10μM荧光光谱ZTRS面对不同的金属离子在溶液中(CH3CN / 5米HEPES(pH 740)50:50)。 激励在360海里。(b)。ZTRS荧光光谱,在不同浓度的Zn2 +。插图显示工作的阴谋 在荧光共10μMaddition浓度的结果在blue-shift HTM离子的温室气体的排放 在CH3CN(支持信息和DMSO数字 8、学生9)。然而,一个小blue-shift最多的吸收 在CH3CN的ZTRS DMSO溶液,, Zn2之外,Cd2 + +的信息,数据(支持 S10-S15)表明,red-shifted发射不结果 从离子氨基NH集团,因为这个 离子的尼克-海德菲尔德组1、8-naphthalimide分子 将导致可吸收光谱。18h 25a,这些吗 近红外光谱数据表明ZTRS联结Zn2 +和Cd2 + tautomeric形式,根据不同的溶剂和金属 (三);离子配合方案ZTRS两Zn2 +和Cd2 + 在CH3CN tautomer酰胺酸tautomer,imidic DMSO为主。然而,其他HTM离子结合了 在CH3CN tautomer酰胺及DMSO溶液。 进一步的证据,imidic酰胺酸tautomeric 结合模式(3)提供方案经核磁共振氢谱进行了探讨 ZTRS实验与Zn2 +和Cd2 +在CD3CN(支持 S16竞赛信息、数据、DMSO-d6(支持) 信息,数据S18,睡着的ZTRS)、二维NOESY / Zn2 +(1:1)在CD3CN复杂数据,支持信息(三, S21一言不发,数据),DMSO-d6(数据),S22-23 3, 和红外光谱的ZTRS / Zn2 +(1:1)在CH3CN复杂 S24(支持信息,人物)和DMSO(支持 信息、图索)。作为一个参考,绑定的性质 与Zn2的ZTF +也利用核磁共振检查 和红外光谱。

三溴偶氮胂Tribromo-arsenazo过氧化氢 Hydrogen Peroxide 体系 System动力学 Dynamics光度法 photometric method测定 Analyse铁 iron因为不是很确定,所以不敢给你串起来大概是 Methods for chemical analysis of iron of 。。。

3 bromine Arsenazo - hydrogen peroxide system dynamics Spectrophotometric Determination of iron

化学专业英语文献综述

高吸水性树脂的应用不应该只限于作为卫生用品材料等,它也可以应用于固定酶,还可用于色谱和传感器。因此根据它所具有的特殊作用来探索其新用途,并应用于高科技领域将会迎来又一个销售高峰。吸水机理?高吸水性树脂的分类 我所研究的那一类是?具体一点我在这次实验中所要解决(或研究)的问题是?本设计的实验方案是?三、 文献综述国外发展情况 早在1958年,美国的迈诺和凯塞曼就研究了以硝酸铵为引发剂,将丙睛接枝到多糖上的反应。1974年美国农业部北方研究中心进一步研究并推广了此技术。此后世界各国对高吸水性树脂的品种,制造方法,性能和应用等方面进行了大量的研究,其中成效最大的是美国和日本。1975年美国研究开发成功淀粉—聚丙烯酸系高吸水性树脂并进入市场,从此高吸水性树脂便逐渐形成一个独立新兴的科研领域。对它的研发工作方兴未艾,尤其是日本后来居上。首先是日本三洋化成公司考虑到丙烯睛单体残留在聚合物中有毒性、不安全,于80年代提出了用放射线对各种氧化烯烃作交联处理,合成非离子型高吸水性树脂,其吸水性能力为2000倍,从而打开了合成非离子型高吸水性树脂的大门。对高吸水性树脂的应用研究是美国UCC公司最早(1973年)开始的,但是日本在1978年批准了高吸水性树脂应用于卫生用品,并最先(1981年)将它大规模地用于卫生用品。用它制作的卫生巾、纸尿布等不仅重量轻、吸液量大、保水性好,而且安全无毒,因此深受广大消费者的欢迎。由于日本、欧美等国纸尿布的迅速普及,高吸水性树脂的用量也相应猛增,各生产公司一方面竞相采用不同的原料、不同的合成工艺和合成方法,另一方面则纷纷扩大装置,提高生产能力。1980年全世界高吸水性树脂生产能力不足5kt/a;1989年,生产能力达到了207kt/a;1994年则达450kt/a;1996年高达846kt/a,开始出现供过于求的现象。针对这一状况,日本、欧美各高吸水性树脂大公司,一方面努力开拓国内市场,提高产品普及率,积极开拓新的应用领域。如日本用高吸水性树脂改造沙漠。另一方面,他们纷纷把目光投向国外市场。如今的日本,高吸水性树脂工业主要依赖高增长出口,这已成为其发展主要动力。从上述过程来看,日本在高吸水性树脂原料、工艺创新和应用方面大有后来居上的派头。 2000年全世界高吸水性树脂生产能力已超过1000kt/a,并以7~8%的速度递增。国内发展情况我国从80年代初开始了对吸水性树脂的研究工作,1985年北京化工研究院申请了国内第一项吸水性树脂专利,随后有二十多家科研单位从事此类产品的研究。约有20家企业建立了中试及小试生产装置,如:北京化学研究院、长春应化所、北京化学所、兰州化物所、抚顺化验院、吉林石化所、黑龙江石化所等。1994年无锡市海龙公司首先建立千吨级生产装置,吴江市浦江树脂厂、保定市科瀚树脂厂、唐山市博亚公司、吉林梨树酿酒总厂、廊坊广润化工公司、黑龙江北安旭光化工总厂等先后建成百吨至千吨级装置。1998年全国生产能力为6000t,实际产量1200t,科瀚厂首批出口2t。我国从20世纪80年代开始对高吸水性树脂进行研究,至今已有几十家单位从事高吸水性树脂的研究。自1991年开始使用吸水性树脂,1994年的用量约为1300t,1998年消费量约为6000t,2000年达到10000t。目前国内所需的吸水性树脂大部分从国外进口,特别是广东、福建、上海、山东等沿海地区和中外合资卫生制品公司。有消息报道,沿海地区通过各种渠道每年进口量可达5万t,进口售价为0万~5万元/t。国内吸水性树脂的生产成本一般在2万~5万元/t,市场售价为8万~2万元/t。目前,高吸水剂还处于起步发展阶段,尤其在基础理论方面研究还较少,国内众多文献还多只集中于研究其合成及其吸纯水性能,对树脂在盐溶液中吸收性能的研究则很少,尤其是吸水性树脂在吸水后的性能研究则更加欠缺。吸水机理高吸水性树脂在水中的溶胀过程,实际上是两种相反趋势的平衡过程。溶剂力图渗入高吸水性树脂的内部,使树脂体积膨胀,引起树脂的伸展;交联点之间的分子链的伸展降低了它的构象嫡,引起了分子网格的弹性收缩力,力图使交联网格收缩。当这两种相反倾向相互抵消时,就达到了溶胀平衡。高吸水性树脂是由三维空间构成的高聚物,它的吸水既有物理吸附,又有化学吸附。当水与高聚物表面接触时,有三种相互作用:一是水分子与高分子电负性强的氧原子形成键结合;二是水分子与疏水基团的相互作用;三是水分子与亲水基团的相互作用。高吸水性树脂在结构上是轻度交联的空间网络结构。由化学交联和树脂分子链间的相互缠绕的物理交联构成。吸水前,高分子长链相互靠拢缠在一起,彼此交联形成网状结构,从而达到整体上的紧固程度。高吸水性树脂可以看成是高分子电解质组成的离子网络和水的构成物。在这种离子网络中,存在着高分子电解质的离子组成的可移动的离子对。高吸水性树脂的吸水过程是一个很复杂的过程。吸水前,高分子网络是固态网束,未电离成离子对。当遇水时,亲水基与水分子的水合作用使高分子网束张展,产生网络内外离子浓度差。如高分子网络结构中有一定数量的亲水离子,就会在网络结构内外产生渗透压,水分子因渗透压作用向网络结构内渗透。同理,被吸附水中含有盐时,渗透压降低,吸水能力随之降低。由此可见,高分子网结构的亲水基离子是不可缺的,它起着张网作用,同时产生渗透功能。亲水离子对是高吸水性树脂能够完成吸水全过程的动力因素。高分子网结构持有大量的水合离子是影响高吸水性树脂吸水能力、加快吸水速度的另一个因素。高吸水性树脂的分类按原料来源分为:淀粉系高吸水性树脂、纤维素系高吸水性树脂、合成系高吸水性树脂、蛋白质系高吸水性树脂、共混与复合系高吸水性树脂、其他天然高分子化合物及其衍生物系高吸水性树脂。本论文中是以膨润土、丙烯酸、丙烯酰胺合成高吸水性树脂,属于共混与复合系高吸水性树脂。  高吸水性树脂的发展趋势随着高吸水性树脂性能的提高,应用范围也大大拓宽。它可以作为土壤保水剂应用在农、林方面,在土壤中添加少量的高吸水性树脂可以提高某些豆类的发芽率和抗旱能力,并能增加土壤的透气性;它可以作为增稠剂用于化妆品的乳液中,加入少量将使乳液粘度增加很大;它可以作为高吸水剂应用于纸尿布、卫生巾等卫生用品中,能抑制由于外压而逆渗出水现象的出现;它可以作为防雾薄膜、抗结露薄膜应用于新的包装材料,可以使食品保持应有的鲜度;它可以作为工业用脱水剂用于除去油和有机溶剂中的水分;它可以作为药物缓释剂应用于医学领域,有效控制药物释放;由于高吸水性树脂还具有无毒和可生物降解等优点,它将会愈来愈多的应用于工业、农业、医疗卫生和日常生活的各个领域。四、 拟解决的关键问题本论文以丙烯酸、丙烯酞胺和膨润土为主要原料,环己烷为分散介质,利用反相悬浮聚合的方法合成膨润土/聚丙烯酸钠/丙烯酞胺复合型的高吸水性树脂。具体的研究内容如下:(1)以丙烯酸、丙烯酞胺和蒙脱土矿物为主要原料,环己烷为分散介质,利用反相悬浮聚合的方法合成聚丙烯酸钠/丙烯酞胺/蒙脱土复合型的高吸水性树脂。(2)对丙烯酸中和度、引发剂用量、交联剂用量、单体用量配比、膨润土(钠基的和有机的)用量、温度等对产物吸水性能的影响进行了研究。(3)对最佳条件下所制得的产品进行吸液性能测试,主要是吸煤泥水倍率、重复吸水能力、恒定温度下保水能力测试等。

其实就是要你总结一下你引用或者查到的资料都讲了写什么,这些资料中都有那些观点,你研究的这个领域现在是一个什么情况,你自己总结一下,然后稍微展开一点,看你们有没有字数要求了。格式可以大致分3部分,1-概括说一下你研究的课题,2-查到的资料的总结3-你写这篇的角度,或如何运用资料等,没有定式啦

文献综述是在确定了选题后,在对选题所涉及的研究领域的文献进行广泛阅读和理解的基础上,对该研究领域的研究现状(包括主要学术观点、前人研究成果和研究水平、争论焦点、存在的问题及可能的原因等)、新水平、新动态、新技术和新发现、发展前景等内容进行综合分析、归纳整理文献综述和评论,并提出自己的见解和研究思路而写成的一种不同于毕业论文的文体。它要求作者既要对所查阅资料的主要观点进行综合整理、陈述,还要根据自己的理解和认识,对综合整理后的文献进行比较专门的、全面的、深入的、系统的论述和相应的评价,而不仅仅是相关领域学术研究的“堆砌”。 你可以检索一些文件,有些数据库里面可以找到相关的内容,如万方,维普等数据库。但是需要钱才可以下载哦。

Application of several catalysts such as lithium perchlorate, zinc chloride, pyridine, triethylamine, 4-(N,N-dimethylamino)pyridine in the preparation of t-butyl acetate via anhydride method was reviewed with 8 Hope you will find the translation

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