财政支持由美国明尼苏达大学（启动资金）和ACS石油研究基金（54225-DNI3）提供。设备采购的化学系核磁共振设备通过来自美国国立卫生研究院（S10OD011952）的资助来自美国明尼苏达大学配套资金的支持。我们承认明尼苏达核磁共振中心为高温NMR。资助核磁共振仪器由副总统办公室的研究，医学院，生物科学，美国国立卫生研究院，美国国家科学基金会的学院和明尼苏达州医学基金会提供的。我们感谢约翰·沃尔泽（埃克森美孚）为PEEK高通量的搅拌桨的礼物。

注意：使用前请咨询所有相关的材料安全数据表（MSDS）。几个在这些合成中使用的化学物质是剧毒和致癌性，而几个是引火并点燃在空气中。执行这些反应包括利用工程控制（通风橱，手套箱）和个人防护装备时，请使用所有适当的安全措施（安全眼镜，手套，实验室外套，全长长裤，闭趾鞋）。下面的过程部分涉及标准的无空气的处理技术。 1.制备[双（2,6-二甲基苯基）-2,3- butanediimine]的NIBR 2，21-25 <ol><li>双（2,6-二甲基苯基）-2,3- butanediimine：（α-二亚胺） <ol><li>溶解2,3​​-丁二酮（1.0毫升，11毫摩尔）和2,6-二甲基苯胺（2.8毫升，23毫摩尔）于20毫升甲醇中的100ml圆底烧瓶中。 </li><li>添加甲酸（0.4毫升，11毫摩尔），搅拌反应一吨室温直到二亚胺沉淀（通常为1-2小时，但可放置过夜）。如果沉淀不形成，集中使用旋转蒸发器和冷却在冰浴中，将反应混合物。 </li><li>过滤用玻璃料和过滤烧瓶中的反应混合物和洗涤黄色固体用20ml冷甲醇和干燥，真空浓缩。 注：1 H NMR（500兆赫，CD 2 Cl 2中）：δ7.06（D，J = 7.6Hz赫兹，4H），6.92（吨，J = 7.5Hz赫兹，2H），2.00-1.99（米，19H）。 </li></ol></li><li>的（1,2-二甲氧基乙烷）NIBR 2制备 ：DME-NIBR 2 <ol><li>在氮气气氛下，在2-颈圆底烧瓶装有回流冷凝器和橡胶结合无水溴化镍（NIBR 2,15克，0.069摩尔），原甲酸三乙酯（30毫升，0.185摩尔）和甲醇（100ml）隔膜上在氮气气氛下在Schlenk线。 </li><li>在氮气氛下回流棕色反应混合物，直到绿色解决方案的形式。这通常需要2-3小时，但该反应可留在必要回流过夜。 </li><li>使混合物冷却后，集中使用上的Schlenk线真空泵以形成暗绿色凝胶的反应混合物中。 </li><li>插管转移过量1,2-二甲氧基乙烷（DME，100毫升）中上果岭凝胶，它立即形成橙色固体。一旦所有的DME加入，加热在85℃下反应另外的2小时，直到浅橙色反应混合物的形式。将反应冷却到室温，此时的光橙色固体沉淀物。 </li><li>从反应烧瓶中取出回流冷凝器和替换的Schlenk玻璃料在氮气气氛下连接到第二个Schlenk接收瓶。 180°使橙色反应混合物进入的Schlenk玻璃料和过滤反应混合物旋转整个装置。 </li><li>取出原有的反应瓶中，放在隔膜的舒伦克星期五吨。套管传送的DME（100ml）中，然后戊烷（100毫升）洗DME-NIBR 2。干燥固体橙色真空带入手套箱。 注意：DME-NIBR 2可以无限期地在室温下在氮气氛下被存储。当敞开于大气中，它形成了一个绿，水合凝胶。 </li></ol></li><li> （〔α二亚胺] NIBR 2）：[双（2,6-二甲基苯基）-2,3- butanediimine] NIBR 2的制备<ol><li>在手套箱，结合DME-NIBR 2（1.0克，3.2毫摩尔）和双（2,6-二甲基苯基）-2,3- butanediimine（1.1克，3.8毫摩尔）在50毫升圆底烧瓶中。 </li><li>加入20ml二氯甲烷，搅拌过夜，在室温下进行。 </li><li>过滤用玻璃料和过滤烧瓶内的反应混合物中。 在真空下洗涤棕色固体用75毫升二氯甲烷和干燥。 注意：此镍催化剂可以无限期储存在惰性气氛手套箱中在室温下。它是人大多数溶剂使不溶性的，并没有进行这样的标准刻画。 </li></ol></li></ol> 2.催化制备储备液<ol><li>储备溶液-的〔〔α二亚胺]的Ni（CH 3）] + [MAO制备<ol><li>通过加入0.0041克〔α二亚胺] NIBR 2（8.0×10 -6摩尔）到小瓶用7.5毫升甲苯制备一1.0×10 -3 M的催化剂储备溶液。 </li><li>向搅拌的镍悬浮液，在甲苯添加0.50 ml的30％甲基铝氧烷（MAO）的搅拌1分钟。颜色会从一个棕色悬浮液变为蓝绿色溶液。这种溶液可以储存在-30℃达6小时，并在随后的聚合反应中使用。 注：甲基铝氧烷是自燃的，并会在空气中吸烟。它应该只在惰性气氛手套箱中使用和护理应该从手套箱中除去污染的注射器/玻璃器皿时服用。典型地，一个注射器第二玻璃器皿都用甲苯洗涤，在手套箱，并放置在一个金属罐，从的Kimwipes或任何其他易燃物质分离。被污染的甲苯被盖住在小瓶中，并从与金属罐手套箱取出。这些项目被转移到通风橱那里打开到空气和使其缓慢猝灭防护玻璃的后面。 </li></ol></li><li>的ZnEt 2原液制备<ol><li>通过1.75毫升的甲苯溶解0.25毫升ZnEt 2准备1.2M的解决方案。 注：二乙基锌是自燃的，并会在空气中点燃。它应该只在惰性气氛手套箱中使用和护理应该从手套箱中除去污染的注射器/玻璃器皿时服用。典型地，注射器和玻璃器皿都用甲苯洗涤，在手套箱，并放置在一个金属罐，从的Kimwipes或任何其他易燃物质分离。被污染的甲苯被盖住在小瓶中，并从与金属罐手套箱取出。帖Ë项目被转移到它们打开到空气的通风柜并使其缓慢猝灭防护玻璃的后面。 </li></ol></li></ol> 3.催化聚合中使用并行高压反应器<ol><li>压力范围<ol><li>设置在平行压力反应器中的所有的聚合反应顶置搅拌容纳在N 2气氛手套箱。编程在软件中聚合：表示总反应体积（3.0毫升）中，所述吹扫气体（N 2），所需的反应气体（乙烯），期望的压力（15-150 psi）的，和所需的反应时间（1小时）。 注：Biotage柱奋进并行高压反应器与能够监视气体吸收用于聚合的一个单独的计算机。所有聚合反应进行至少三次，以确保准确性和再现性。使用这种类型的反应器中的几个变量的可在单次实验中或在多个exp的过程来调节eriments包括：将反应气体，压力，温度，时间，溶剂，体积，催化剂，或链转移试剂。通过执行8反应在具有实时气体摄取时间，催化反应被有效地检测。在这种情况下，反应小瓶有5毫升的最大体积，因此，3毫升的体积被选择占聚合物的形成。另外，标准浓度，压力和时间是根据文献的条件。21，这些聚合反应可在单个反应器中的压力或甚至在Schlenk线上的所有来完成，但它是更难以实现更高的压力或气体吸收的反应。 </li><li>将玻璃衬反应小瓶到8口井。使用深度工具，以确保玻璃衬里在适当的高度。将叶片叶轮进入塔顶组装。 </li><li> 根据表1填充反应小瓶： <table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td> 反应釜 </td><td> 压力（psi） </td><td> 催化剂卷。 （毫升） </td><td> ZnEt 2卷。 （毫升） </td><td> 甲苯卷。 （毫升） </td></tr><tr><td> 1 </td><td> 15 </td><td> 0 </td><td> 0 </td><td> 3 </td></tr><tr><td> 2 </td><td> 15 </td><td> 0.1 </td><td> 0 </td><td> 2.9 </td></tr><tr><td> 3 </td><td>三十</td><td> 0 </td><td> 0 </td><td> 3 </td></tr><tr><td> 4 </td><td>三十</td><td> 0.1 </td><td> 0 </td><td> 2.9 </td></tr><tr><td>五</td><td> 60 </td><td> 0 </td><td> 0 </td><td> 3 </td></tr><tr><td> 6 </td><td> 60 </td><td> 0.1 </td><td> 0 </td><td> 2.9 </td></tr><tr><td> 7 </td><td> 150 </td><td> 0 </td><td> 0 </td><td> 3 </td></tr><tr><td> 8 </TD&gt; <td> 150 </td><td> 0.1 </td><td> 0 </td><td> 2.9 </td></tr></tbody></table> 表1中。反应条件为，压力范 ​​围的反应。 </li><li>保证O形环在金属槽正确就位并小心地将顶部搅拌装配在基座上，并以交替方式拧紧。确保所有的螺丝是否拧紧，然后按开始在软件中。 监测经过气体吸收测量反应。 </li><li> 1小时聚合后，从手套箱中取出反应小瓶中并沉淀聚乙烯与在甲醇中加入5％盐酸，除去溶剂并真空干燥。质量的聚合物，以获得产率和在反应过程中进行比较的乙烯消耗。 </li><li>计算催化剂，它是每摩尔催化剂形成的聚合物的质量，每小时聚合的活性。 </li><li>分析分子量和分散度指数干燥聚乙烯采用高温凝胶渗透色谱法（GPC）。溶解0.002克的聚合物在2毫升1,2,4-三氯苯在135℃。根据制造商的协议运行GPC中。 注意：使用Agilent PL-GPC 220高温GPC / SEC系统被用于在135℃和使用聚苯乙烯标准来分析聚合物的分子量数据为适合。 </li><li>分析支化度时，分支型，并使用高温。13 C NMR干燥聚乙烯的末端基团类型。溶解0.050-0.080克聚合物在0.5ml四氯乙烷-D 2（C 2 D 2氯4）在130℃。运行在600MHz的NMR样品在130℃下至少2000扫描。分支根据文献分配聚合物26-28 注意：安捷伦/瓦里安600MHz的光谱仪上在130℃下用于13 C NMR分析。 </li></ol></li><li>链转移聚合<ol><li>按照相同的程序，并分析作为第3.1节，填充在反应器和编程根据表 2中的参数的软件： <table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td> 反应釜 </td><td> 压力（psi） </td><td> 催化剂卷。 （毫升） </td><td> ZnEt 2卷。 （毫升） </td><td> 甲苯卷。 （毫升） </td></tr><tr><td> 1 </td><td> 60 </td><td> 0.1 </td><td> 0 </td><td> 2.9 </td></tr><tr><td> 2 </td><td> 60 </td><td> 0.1 </td><td> 0.005 </td><td> 2.9 </td></tr><tr><td> 3 </td><td> 60 </td><td> 0.1 </td><td> 0.01 </td><td> 2.89 </td></tr><tr><td> 4 </td><td> 60 </td><td> 0.1 </td><td> 0.015 </td><td> 2.89 </td></tr><tr><td>五</td><td> 60 </td><td> 0.1 </td><td>0.025 </td><td> 2.88 </td></tr><tr><td> 6 </td><td> 60 </td><td> 0.1 </td><td> 0.042 </td><td> 2.86 </td></tr><tr><td> 7 </td><td> 60 </td><td> 0.1 </td><td> 0.06 </td><td> 2.84 </td></tr><tr><td> 8 </td><td> 60 </td><td> 0.1 </td><td> 0.085 </td><td> 2.82 </td></tr></tbody></table> 表2中。反应条件为链转移聚合反应。 </li><li>此外，计算链由于ZnEt 2的存在和每基于以下等式催化剂的摩尔发起链数延长的摩尔数。7 <img alt="式（1）" src="/files/ftp_upload/53212/53212eq1-2.jpg" width="250" /> （MR）扩展-链摩尔扩展由于ZnEt 2的存在下（摩尔） 产量聚合物 -聚合物的形成团块（G） Mn为-号AVER从GPC的聚合物的年龄分子量（克/摩尔） 链发起 -每摩尔催化剂发起链数 摩尔催化剂 -摩尔催化剂的聚合中使用</li><li>请启动对ZnEt 2的浓度数量链的情节。 </li></ol></li></ol>聚合反应4.动力学分析：链转移和传播率<ol><li>速率传输的（K P） <ol><li>每次运行在仅〔α二亚胺] NIBR 2存在时，使乙烯消耗量与时间的关系的曲线图。 </li><li>适合的初始乙烯气体吸收于线状区域，以获得起始速率。在图2a的情况下，该痕迹适合为500〜2000秒。 </li><li>使用斜坡的平均，得到传播（K p）的速率为在所需压力下的特定催化剂。 </li></ol></li><li>比率链转移（K P） <ol><li>通过找到气体的消耗在不包含催化剂的反应器的摩尔数判断乙烯的浓度，[C 2 =]，3.0 ml的从平均气体吸收（溶解度）甲苯。 </li><li>使1 / M n的梅奥图（从GPC求出的分子量数据）与[ZNR X] / [C 2 =]（从ZnEt 2的浓度置于反应器中）。7，29 </li><li>适合数据基于所述梅奥方程的直线。乘以28的斜率，乙烯的分子量，得到的链转移到传播速率（K E / K P＆）的速率之比。 <img alt="公式3" src="/files/ftp_upload/53212/53212eq3.jpg" width="230" /> MN -从GPC的聚合物的数均分子量与ZnEt 2 M NØ -数均从GPC的聚合物的分子量，而不ZnEt 2 K E特征-价格链转移的 K P＆ -传播率 [ZNR X] - ZnEt 2的浓度在反应 [C 2 =] -乙烯在反应浓度 28 - 乙烯的分子量</li><li>乘法K E特征 / K P＆由前一节中所得到的K p来得到的链转移K E特征的速率。 </li></ol></li></ol>

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J., Cibuzar, M. P., Tonks, I. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+Polymeryl+Chain+Transfer+Between+Group+10+Metals+and+Main+Group+Alkyls+during+Ethylene+Polymerization.">Analysis of Polymeryl Chain Transfer Between Group 10 Metals and Main Group Alkyls during Ethylene Polymerization.</a> ACS Catalysis. 4 (11), 4223-4231 (2014).</li><li>Johnson, L. K., Killian, C. M., Brookhart, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+Pd(II)-+and+Ni(II)-Based+Catalysts+for+Polymerization+of+Ethylene+and+.alpha.-Olefins.">New Pd(II)- and Ni(II)-Based Catalysts for Polymerization of Ethylene and .alpha.-Olefins.</a> J. Am. Chem. Soc. 117 (23), 6414-6415 (1995).</li><li>Ittel, S. D., Johnson, L. 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E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NMR+study+on+the+coordination+behavior+of+dissymmetric+terdentate+trinitrogen+ligands+on+methylpalladium(II)+compounds.">NMR study on the coordination behavior of dissymmetric terdentate trinitrogen ligands on methylpalladium(II) compounds.</a> Inorg. Chem. 32 (25), 5769-5778 (1993).</li><li>Ward, L. G. L., Pipal, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anhydrous+Nickel+(II)+Halides+and+their+Tetrakis+(Ethanol)+and+1,2-Dimethoxyethane+Complexes.">Anhydrous Nickel (II) Halides and their Tetrakis (Ethanol) and 1,2-Dimethoxyethane Complexes.</a> Inorg. Syntheses. 13, 154-164 (1972).</li><li>Galland, G. B., de Souza, R. F., Mauler, R. S., Nunes, F. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=13C+NMR+Determination+of+the+Composition+of+Linear+Low-Density+Polyethylene+Obtained+with+[&#951;3-Methallyl-nickel-diimine]PF6+Complex.">13C NMR Determination of the Composition of Linear Low-Density Polyethylene Obtained with [&#951;3-Methallyl-nickel-diimine]PF6 Complex.</a> Macromolecules. 32 (5), 1620-1625 (1999).</li><li>Cotts, P. M., Guan, Z., McCord, E., McLain, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+Branching+Topology+in+Polyethylenes+As+Revealed+by+Light+Scattering+and+13C+NMR.">Novel Branching Topology in Polyethylenes As Revealed by Light Scattering and 13C NMR.</a> Macromolecules. 33 (19), 6945-6952 (2000).</li><li>Wiedemann, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monofunctional+hyperbranched+ethylene+oligomers.">Monofunctional hyperbranched ethylene oligomers.</a> J. Am. Chem. Soc. 136 (5), 2078-2085 (2014).</li><li>Mayo, F. 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甲基取代的阳离子[α-二亚胺] NIBR 2 与MAO活化的乙烯聚合催化剂进行其能力为乙烯链转移聚合。将反应物通过气体吸收测量监测，以确定的速率和聚合和催化剂寿命的程度， 并通过凝胶渗透色谱（GPC）测定所获得的聚合物的分子量。最初，镍催化剂进行试验的范围内的乙烯压力（从15-225磅），以确定最佳条件为这个系统在不存在ZnEt 2。使用催化剂的3.33×1...

聚烯烃工业的聚合物与用于热塑性塑料和弹性体的一类重要的。在单点催化剂生产聚烯烃的设计显著进步导致了能够调整分子量，多分散性，和聚合物微结构，这导致了广泛的潜在应用。1-3最近，链转移和链穿梭聚合已经开发，得到附加路由来修改聚合物的性能而无需修改该催化剂。4-6该系统使用单中心过渡金属催化剂和链转移试剂（CTR），它通常是主族金属烷基。在此聚合中，正在生长的聚合物链是能够从催化剂的点击率，其中聚合物链保持休眠，直到它被转移回催化剂转移。同时，被转移到催化剂的烷基可以发起肛疗法聚合物链。在链转移聚合，一种催化剂可以启动一个更大数量的链相对于标准催化聚合。聚合物链终止，该链转移金属;因此，进一步的端基功能化是可能的。该系统可用于改变分子量和聚烯烃的分子量分布，7催化上主族金属，第8和涉及multicatalyst系统，如嵌段共聚物特种聚合物的合成Aufbau状烷基链的增长。9， 10 链转移聚合已观察到最常见的与前过渡金属（铪，锆）和烷基锌或烷基铝试剂，尽管实施例在整个过渡金属系存在。5,7,8,11-16在典型的前过渡金属催化剂体系，链转移是快速，高效，可逆导致窄的分子量分布。章艾因传输/穿梭已中旬至下旬的过渡金属 （如铬，铁，钴和镍）与第2组和第12烷基金属，虽然比起早期的金属传输的速率变化很大。4,7被观察到， 17-19的两个主要因素是所需的必要的有效的链转移：具有良好的金属-碳键离解能匹配的聚合催化剂和链转移试剂，和合适的空间位阻环境以促进烷基桥连的双金属中间体双分子形成/破损20在后过渡金属的情况下，如果催化剂不包含足够的空间体积，β-氢化物（β-H）消除将是占主导地位的终止途径和一般会失竞争的链转移。 本文我们就从镍-2,3- butanediimine类催化剂体系通过SMA双金属链转移到锌的双（2,6-二甲基苯基）二乙基锌与（ZnEt 2）的研究报告LL-大规模高通量的反应。链转移将通过检查通过凝胶渗透色谱分析中的变化分子量（M w）的和所得到的聚乙烯的分散度指数来识别。链转移还将通过乙烯基的饱和链端作为链转移剂浓度的函数的比率的13 C NMR分析鉴定。传播和链转移的速率的深入动力学分析也将提交。

<table border="0" cellpadding="0" cellspacing="0" style="width:675px;" width="674">
	<tbody>
		<tr height="25">
			<td height="25" style="height:25px;width:209px;">Endeavor Pressure Reactor</td>
			<td style="width:119px;">Biotage</td>
			<td style="width:107px;">EDV-1N-L</td>
			<td style="width:240px;"></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Blade Impellers</td>
			<td>Biotage</td>
			<td>900543</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Glass Liners</td>
			<td>Biotage</td>
			<td>900676</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">2,3-butanedione, 99%</td>
			<td>Alfa Aesar</td>
			<td>A14217</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">2,6-dimethylaniline, 99%</td>
			<td>Sigma Aldrich</td>
			<td>D146005</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">formic acid, 95%</td>
			<td>Sigma Aldrich</td>
			<td>F0507</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">methanol, 99.8%</td>
			<td>Sigma Aldrich</td>
			<td>179337</td>
			<td>ACS Reagent</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">nickel (II) bromide, 99%</td>
			<td>Strem</td>
			<td>28-1140</td>
			<td>anhydrous, hygroscopic</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">triethylorthoformate, 98%</td>
			<td>Sigma Aldrich</td>
			<td>304050</td>
			<td>dried with K2CO3 and distilled</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">1,2-dimethoxyethane, 99.5%</td>
			<td>Sigma Aldrich</td>
			<td>259527</td>
			<td>dried with Na/Benzophenone and distilled</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">pentane, 99%</td>
			<td>Fisher</td>
			<td>P399</td>
			<td>HPLC Grade *</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">dichloromethane, 99.5%</td>
			<td>Fisher</td>
			<td>D37</td>
			<td>ACS Reagent *</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">toluene, 99.8%</td>
			<td>Fisher</td>
			<td>T290</td>
			<td>HPLC Grade *</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">methylaluminoxane</td>
			<td>Albemarle</td>
			<td>MAO</td>
			<td>pyrophoric, 30% in toluene</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">diethylzinc, 95%</td>
			<td>Strem</td>
			<td>93-3030</td>
			<td>pyrophoric</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">1,2,4-trichlorobenzene, 99%</td>
			<td>Sigma Aldrich</td>
			<td>296104</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">1,1,2,2-tetrachloroethane-D2, 99.6%</td>
			<td>Cambridge Isotopes</td>
			<td>DLM-35</td>
			<td></td>
		</tr>
	</tbody>
</table>

ethylene polymerizations using parallel pressure reactors and a kinetic analysis of chain transfer polymerization

我们证明高通量催化剂使用平行压力反应器由镍α-二亚胺乙烯聚合催化剂的初始合成起始筛选的方法。初始聚合用催化剂导致优化的反应条件，包括催化剂浓度，乙烯压力和反应时间。使用气体摄取数据用于这些反应的，一个过程来计算传播（K p）的初始速率呈现。使用优化的条件下，镍α二亚胺聚合催化剂的能力乙烯聚合期间经历与二乙基锌（ZnEt 2）链转移进行了研究。的过程来评估催化剂的经过链转移（从分子量和 13 C NMR数据），计算链转移的程度，并计算链转移速率（K e）中呈现的能力。

乙烯气体消耗与时间的关系示于图1所测试的不同的乙烯压力。这个数据被用于确定优化的反应条件。乙烯气体消耗与时间的关系示于图2A中用于催化剂单独的样品，其中用于计算传播（K p）的速率。 图2B示出的凝胶渗透色谱（GPC）用于链转移聚合痕迹与0-1,000当量二乙基锌。 GPC的用于计算的聚合物样品，其示</stro...

Watch this Scientific Journal Video about Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization at JoVE.com

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

一种协议，用于聚合催化剂，链转移聚合，聚乙烯表征和反应动力学分析的高通量分析，提出。

乙烯聚合中使用并联电抗器的压力和链转移聚合的动力学分析

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel ...

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12.7K 次观看.  University of Minnesota - Twin Cities. 一种协议，用于聚合催化剂，链转移聚合，聚乙烯表征和反应动力学分析的高通量分析，提出。 

视频: Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity

Human 8-oxoguanine DNA glycosylase (OGG1) excises the mutagenic oxidative DNA lesion 8-oxo-7,8-dihydroguanine (8-oxoG) from DNA. Kinetic characterization of OGG1 is undertaken to measure the rates of 8-oxoG excision and product release. When the OGG1 concentration is lower than substrate DNA, time courses of product formation are biphasic; a rapid exponential phase (i.e. burst) of product formation is followed by a linear steady-state phase. The initial burst of product formation corresponds to the concentration of enzyme properly engaged on the substrate, and the burst amplitude depends on the concentration of enzyme. The first-order rate constant of the burst corresponds to the intrinsic rate of 8-oxoG excision and the slower steady-state rate measures the rate of product release (product DNA dissociation rate constant, koff). Here, we describe steady-state, pre-steady-state, and single-turnover approaches to isolate and measure specific steps during OGG1 catalytic cycling. A fluorescent labeled lesion-containing oligonucleotide and purified OGG1 are used to facilitate precise kinetic measurements. Since low enzyme concentrations are used to make steady-state measurements, manual mixing of reagents and quenching of the reaction can be performed to ascertain the steady-state rate (koff). Additionally, extrapolation of the steady-state rate to a point on the ordinate at zero time indicates that a burst of product formation occurred during the first turnover (i.e. y-intercept is positive). The first-order rate constant of the exponential burst phase can be measured using a rapid mixing and quenching technique that examines the amount of product formed at short time intervals (&lt;1 sec) before the steady-state phase and corresponds to the rate of 8-oxoG excision (i.e. chemistry). The chemical step can also be measured using a single-turnover approach where catalytic cycling is prevented by saturating substrate DNA with enzyme (E&gt;S). These approaches can measure elementary rate constants that influence the efficiency of removal of a DNA lesion.

Time courses for the glycosylase activity of 8-oxoguanine DNA glycosylase are biphasic exhibiting a burst of product formation and a linear steady-state phase. Utilizing quench-flow techniques, the burst and the steady-state rates can be measured, which correspond to excision of 8-oxoguanine and release of the glycosylase from the product DNA, respectively.

稳态，稳定前的状态，单营业额动力学测量DNA糖基化酶活性

Human 8-oxoguanine DNA glycosylase (OGG1) excises the mutagenic oxidative DNA lesion 8-oxo-7,8-dihydroguanine (8-oxoG) from DNA. Kinetic characterization ...

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化学

Microwave-assisted Functionalization of Poly(ethylene glycol) and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation

One of the main benefits to using poly(ethylene glycol) (PEG) macromers in hydrogel formation is synthetic versatility. The ability to draw from a large variety of PEG molecular weights and configurations (arm number, arm length, and branching pattern) affords researchers tight control over resulting hydrogel structures and properties, including Young&#8217;s modulus and mesh size. This video will illustrate a rapid, efficient, solvent-free, microwave-assisted method to methacrylate PEG precursors into poly(ethylene glycol) dimethacrylate (PEGDM). This synthetic method provides much-needed starting materials for applications in drug delivery and regenerative medicine. The demonstrated method is superior to traditional methacrylation methods as it is significantly faster and simpler, as well as more economical and environmentally friendly, using smaller amounts of reagents and solvents. We will also demonstrate an adaptation of this technique for on-resin methacrylamide functionalization of peptides. This on-resin method allows the N-terminus of peptides to be functionalized with methacrylamide groups prior to deprotection and cleavage from resin. This allows for selective addition of methacrylamide groups to the N-termini of the peptides while amino acids with reactive side groups (e.g.&#160;primary amine of lysine, primary alcohol of serine, secondary alcohols of threonine, and phenol of tyrosine) remain protected, preventing functionalization at multiple sites. This article will detail common analytical methods (proton Nuclear Magnetic Resonance spectroscopy (;H-NMR) and Matrix Assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-ToF)) to assess the efficiency of the functionalizations. Common pitfalls and suggested troubleshooting methods will be addressed, as will modifications of the technique which can be used to further tune macromer functionality and resulting hydrogel physical and chemical properties. Use of synthesized products for the formation of hydrogels for drug delivery and cell-material interaction studies will be demonstrated, with particular attention paid to modifying hydrogel composition to affect mesh size, controlling hydrogel stiffness and drug release.

Microwave-assisted Functionalization of Polyethylene glycol and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation

This video will illustrate a rapid, efficient method to methacrylate poly(ethylene glycol), enabling chain polymerizations and hydrogel synthesis. It will demonstrate how to similarly introduce methacrylamide functionalities into peptides, detail common analytical methods to assess functionalization efficiency, provide suggestions for troubleshooting and advanced modifications, and demonstrate typical hydrogel characterization techniques.

保利的微波辅助功能化（乙二醇）和On-树脂链聚合反应，并形成水凝胶的肽使用

One of the main benefits to using poly(ethylene glycol) (PEG) macromers in hydrogel formation is synthetic versatility. The ability to draw from a large ...

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. Specifically, the sapphire cell enables visual data collection from multiple loadings to solve a set of material balances to precisely determine phase composition. Ternary phase diagrams can then be established to determine the proportion of each component in each phase at a given condition. In principle, any ternary system can be studied although ternary systems (gas-liquid-liquid) are the specific examples discussed herein. For instance, the ternary THF-Water-CO2 system was studied at 25 and 40&#160;&#176;C and is described herein. Of key importance, this technique does not require sampling. Circumventing the possible disturbance of the system equilibrium upon sampling, inherent measurement errors, and technical difficulties of physically sampling under pressure is a significant benefit of this technique. Perhaps as important, the sapphire cell also enables the direct visual observation of the phase behavior. In fact, as the CO2 pressure is increased, the homogeneous THF-Water solution phase splits at about 2 MPa. With this technique, it was possible to easily and clearly observe the cloud point and determine the composition of the newly formed phases as a function of pressure.
The data acquired with the sapphire cell technique can be used for many applications. In our case, we measured swelling and composition for tunable solvents, like gas-expanded liquids, gas-expanded ionic liquids and Organic Aqueous Tunable Systems (OATS)1-4. For the latest system, OATS, the high-pressure sapphire cell enabled the study of (1) phase behavior as a function of pressure and temperature, (2) composition of each phase (gas-liquid-liquid) as a function of pressure and temperature and (3) catalyst partitioning in the two liquid phases as a function of pressure and composition. Finally, the sapphire cell is an especially effective tool to gather accurate and reproducible measurements in a timely fashion.

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus is a unique tool to study, without sampling, phase behavior under a wide range of pressures. Using a cathetometer, very precise volume measurements can be recorded to measure liquid expansion and phase composition. Thus, this synthetic method enables the study of (1) phase equilibria of multi-component mixtures and (2) the partition behavior of catalyst or model compounds as a function of pressure.

高压蓝宝石细胞对CO的相平衡测量<sub&gt; 2</sub&gt; /有机/水系统

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. ...

Chemical Gardens as Flow-through Reactors Simulating Natural Hydrothermal Systems

Here we report experimental simulations of hydrothermal chimney growth using injection chemical garden methods. The versatility of this type of experiment allows for testing of various proposed ocean / hydrothermal fluid chemistries that could have driven reactions toward the origin of life in environments on the early Earth, early Mars, or even other worlds such as the icy moons of the outer planets. We show experiments that include growth of chemical garden structures under anoxic conditions simulating the early Earth, inclusion of trace components of phosphates / organics in the injection solution to incorporate them into the structure, a switch of the injection solution to introduce a secondary precipitating anion, and the measurement of membrane potentials generated by chemical gardens. Using this method, self-assembling chemical garden structures were formed that mimic the natural chimneys precipitated at submarine hydrothermal springs, and these precipitates can be used successfully as flow-through reactors by feeding through multiple successive &#8220;hydrothermal&#8221; injections.

We describe chemical garden formation via injection experiments that allow for laboratory simulations of natural chemical garden systems that form at submarine hydrothermal vents.

化工园为直通式反应器模拟自然热液系统

Here we report experimental simulations of hydrothermal chimney growth using injection chemical garden methods. The versatility of this type of experiment ...

Tuning a Parallel Segmented Flow Column and Enabling Multiplexed Detection

Active flow technology (AFT) is new form of column technology that was designed to overcome flow heterogeneity to increase separation performance in terms of efficiency and sensitivity and to enable multiplexed detection. This form of AFT uses a parallel segmented flow (PSF) column. A PSF column outlet end-fitting consists of 2 or 4 ports, which can be multiplexed to connect up to 4 detectors. The PSF column not only allows a platform for multiplexed detection but also the combination of both destructive and non-destructive detectors, without additional dead volume tubing, simultaneously. The amount of flow through each port can also be adjusted through pressure management to suit the requirements of a specific detector(s). To achieve multiplexed detection using a PSF column there are a number of parameters which can be controlled to ensure optimal separation performance and quality of results; that is tube dimensions for each port, choice of port for each type of detector and flow adjustment. This protocol is intended to show how to use and tune a PSF column functioning in a multiplexed mode of detection.

Here, we present a protocol for the operation and tuning of parallel segmented flow chromatography columns to enable multiplexed detection.

调优并行分段流动列和启用多重检测

Active flow technology (AFT) is new form of column technology that was designed to overcome flow heterogeneity to increase separation performance in terms ...

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline elastomers (LCEs) with facile control over network structure and programming of an aligned monodomain. Tailored LCE networks were synthesized using routine mixing of commercially available starting materials and pouring monomer solutions into molds to cure. An initial polydomain LCE network is formed via a self-limiting thiol-acrylate Michael-addition reaction. Strain-to-failure and glass transition behavior were investigated as a function of crosslinking monomer, pentaerythritol tetrakis(3-mercaptopropionate) (PETMP). An example non-stoichiometric system of 15 mol% PETMP thiol groups and an excess of 15 mol% acrylate groups was used to demonstrate the robust nature of the material. The LCE formed an aligned and transparent monodomain when stretched, with a maximum failure strain over 600%. Stretched LCE samples were able to demonstrate both stress-driven thermal actuation when held under a constant bias stress or the shape-memory effect when stretched and unloaded. A permanently programmed monodomain was achieved via a second-stage photopolymerization reaction of the excess acrylate groups when the sample was in the stretched state. LCE samples were photo-cured and programmed at 100%, 200%, 300%, and 400% strain, with all samples demonstrating over 90% shape fixity when unloaded. The magnitude of total stress-free actuation increased from 35% to 115% with increased programming strain. Overall, the two-stage TAMAP methodology is presented as a powerful tool to prepare main-chain LCE systems and explore structure-property-performance relationships in these fascinating stimuli-sensitive materials.

A novel methodology is presented to synthesize and program main-chain liquid-crystalline elastomers using commercially available starting monomers. A wide range of thermomechanical properties was tailored by adjusting the amount of crosslinker, while the actuation performance was dependent on the amount of applied strain during programming.

的可编程主链液晶性弹性体用双级硫醇丙烯酸酯反应合成

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline ...

Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst

A standardized technique for atom transfer radical polymerization of vinyl monomers using perylene as a visible-light photocatalyst is presented. The procedure is performed under an inert atmosphere using air- and water-exclusion techniques. The outcome of the polymerization is affected by the ratios of monomer, initiator, and catalyst used as well as the reaction concentration, solvent, and nature of the light source. Temporal control over the polymerization can be exercised by turning the visible light source off and on. Low dispersities of the resultant polymers as well as the ability to chain-extend to form block copolymers suggest control over the polymerization, while chain end-group analysis provides evidence supporting an atom-transfer radical polymerization mechanism.

A method for the atom transfer radical polymerization of functionalized vinyl monomers using perylene as a visible-light photocatalyst is described.

使用苝作为可见光光催化功能化的乙烯基单体原子转移自由基聚合

A standardized technique for atom transfer radical polymerization of vinyl monomers using perylene as a visible-light photocatalyst is presented. The ...

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

使用Photoredox催化剂蠕虫状胶束的简便合成可见光介导的分散聚合

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

Spin Saturation Transfer Difference NMR (SSTD NMR): A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

This detailed protocol describes the new Spin Saturation Transfer Difference Nuclear Magnetic Resonance protocol (SSTD NMR), recently developed in our group to study processes of mutual-site chemical exchange that are difficult to analyze by traditional methods. As the name suggests, this method combines the Spin Saturation Transfer method used for small molecules, with the Saturation Transfer Difference (STD) NMR method employed for the study of protein-ligand interactions, by measuring transient spin saturation transfer along increasing saturation times (build-up curves) in small organic and organometallic molecules undergoing chemical exchange.
Advantages of this method over existing ones are: there is no need to reach coalescence of the exchanging signals; the method can be applied as long as one signal of the exchanging sites is isolated; there is no need to measure T1 or reach steady state saturation; rate constant values are measured directly, and T1 values are obtained in the same experiment, using only one set of experiments.
To test the method, we have studied the dynamics of the hindered rotation of N,N-dimethylamides, for which much data is available for comparison. The thermodynamic parameters obtained using SSTD are very similar to the reported ones (spin-saturation transfer techniques and line-shape analysis). The method can be applied to more challenging substrates that cannot be studied by previous methods.
We envisage that the simple experimental set up and the wide applicability of the method to a great variety of substrates will make this a common technique amongst organic and organometallic chemists without extensive expertise in NMR.

Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

A detailed protocol describing the SSTD NMR method is presented here to help new users apply this new method to obtain the kinetic parameters of their own systems undergoing chemical exchange.

自旋饱和转移差异核磁共振（NMR SSTD）：一种新的工具来获得化学交换过程的动力学参数

This detailed protocol describes the new Spin Saturation Transfer Difference Nuclear Magnetic Resonance protocol (SSTD NMR), recently developed in our ...

A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic nature of the monomer is conserved. The resulting polymer, polynorbornene, has a very high glass transition temperature, Tg, and interesting optical and electrical properties. However, the polymerization of functional norbornenes by this mechanism is complicated by the fact that the endo substituted norbornene monomer has, in general, a very low reactivity. Furthermore, the separation of the endo substituted monomer from the exo monomer is a tedious task. Here, we present a simple protocol for the polymerization of substituted norbornenes (endo:exo ca. 80:20) bearing either a carboxylic acid or a pendant double bond. The process does not require that both isomers be separated, and proceeds with low catalyst loadings (0.01 to 0.02 mol%). The polymer bearing pendant double bonds can be further transformed in high yield, to afford a polymer bearing pendant epoxy groups. These simple procedures can be applied to prepare polynorbornenes with a variety of functional groups, such as esters, alcohols, imides, double bonds, carboxylic acids, bromo-alkyls, aldehydes and anhydrides.

We describe the catalytic insertion polymerization of 5-norbornene-2-carboxylic acid and 5-vinyl-2-norbornene to form functional polymers with a very high glass transition temperature.

功能性降冰片烯的催化聚合插入一种简单高效的协议

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic ...