由铝土矿制备聚碱式氯化铝

介绍了以铝土矿为原料、实验室制备聚碱式氯化铝的原理和方法，并进行了产品净水效果实验。     

新混凝剂——碱式氯化铝

碱式氯化铝(国外叫聚氯化铝)是一种新型高效无机高分子混凝剂。近六、七年来,有的国家开始生产,应用于水处理方面。遵照毛主席关于“自力更生”的教导,四川省给水排水设计院、成都综合化工厂和成都市自来水公司,在成都市计委、科委以及有关单位大力支持下,于1971年摸索出了利用工业废渣铝灰和盐酸为原料,反应不耗燃料的土法工业生产碱式氯化铝的工艺流程,并于1972年成批生产,供城市自来水厂使用。使用表明,用这种新混凝剂净化饮用水,水质符合国家标准。与旧有混凝剂硫酸铝和三氯化铁对比,具有效率高,耗量低,降低制水成本,改善劳动条件等优点。碱式氯化铝为与碱化度、聚合度、pH、聚合促进剂等因素有关的无机高分子化合物。它是介于三氯化     

混凝剂中铬铅镉砷的示波极谱连续测定

1 引言 目前混凝剂以碱式氯化铝、硫酸铝及各类“聚铁”等使用较为普遍。混凝剂中铬、铅、镉、砷等毒理指标须经检验并符合卫生学要求。我们在氨水-氯化铵-硫酸-碘化钾-亚碲酸钾组成的连续底液中,以示波极谱法简便快速地在一份检样中连续测定这四种元素。其波形清晰,干扰小,结果满意。     

聚己内酯、聚环氧丙烷大单体制备及其与甲基丙烯酸正丁酯共聚合

聚己内酯、聚环氧丙烷大单体制备及其与甲基丙烯酸正丁酯共聚合曹维孝，管治斌，江必旺，冯新德（北京大学化学系北京１００８７１）关键词大单体，聚己内酯，聚环氧丙烷以四苯基卟啉氯化铝（ＴＰＰＡＩ－Ｃｌ）与甲基丙烯酸－β－羟基两酯（ＨＰＭＡ）制备的活性开环催化...     

火焰原子吸收光谱法测定聚氯化铝中锰

火焰原子吸收法测定锰具有选择性好、操作简便等优点.但由于净水剂聚氯化铝中存在大量铝基底,在火焰中生成难熔的氧化物与锰形成混晶或固熔体,影响了锰的原子化,故在一般条件下不能以直接原子光谱法准确测定净水剂聚氯化铝中锰含量.目前,一般采用萃取-原子吸收法及化学法测定聚氯化铝中锰.但此两法有费时或所用萃取剂MIBK有刺激性气味等缺点.我们参照文献[1],在聚氯化铝样液中加入磺基水杨酸作Al~(3 )的配合剂,拟定了火焰原子吸收直接测定聚氯化铝中锰的新方法.该法有效地消除了大量铝     

国强标《生活饮用水用聚氯化铝》报批公示 多项分析方法有变动

<正>3月11日,工业和信息化部科技司发布关于《生活饮用水用聚氯化铝》强制性国家标准报批公示的通知,公示时间:2019年3月11日-2019年4月12日,建议批准发布后6个月实施。内容显示,《生活饮用水用聚氯化铝》(GB 15892—201X)按照GB/T1.1-2009给出的规则起草,规定了生活饮用水用聚氯化铝的要求、试验方法、检验规则、标志、包装、运输和贮存,适用于生活饮用水用聚氯化铝,该产品主要用于生活饮用水的净化。本标准代替G     

聚氯化铝中氧化铝含量的测量不确定度评定

对GB15892-2003测定聚氯化铝中氧化铝含量的测量不确定度进行评定。通过对样品测定过程中影响测量不确定度的因素进行分析和量化,求得聚氯化铝中氧化铝含量测量结果的合成相对标准不确定度为0.0025。     

不同制备工艺聚硅氯化铝的红外光谱和晶貌研究

聚硅金属盐 (主要是铝盐和铁盐 )是一类新型高效无机高分子混凝剂 ,不同的制备工艺会获得分子相对质量不同 ,分子结构有差异 ,因而混凝效果与稳定性能明显不同的产品。由于基础研究过于薄弱 ,严重影响了其实行大规模工业生产[1] 。聚硅氯化铝 (ＰＡＳＣ)属于聚硅金属盐 ,它的制备大多采用将聚硅酸与铝盐混合 ,在陈化中令其自然聚合 (或适当加热 )的方法[2～ 4 ] 。作者在该方法的基础上增加碱化聚合手段 ,继而引入代号为Ａ的聚合助剂 ,使制得的ＰＡＳＣ具有更好的混凝效果[5] 。为此 ,对不同制备工艺的ＰＡＳＣ进行红外光谱和晶形貌象研究 ,…     

1-丁烯齐聚反应(Ⅸ)——羧酸镍/乙基氯化铝催化体系反应机理的讨论

用乙酸镍、2-乙基己酸镍、二乙基氯化铝、倍半乙基氯化铝等组成Ziegler-Natta催化剂催化丁烯齐聚.测定了二聚物组成,讨论了活性物种的形成过程,推导了反应机理.     

CO2辅助老化制备的Cu/ZnO/Al2O3催化剂上CO2加氢制甲醇

对传统共沉淀法进行改进,在老化阶段通入CO2促进母液中前驱体物相的转变,制备了Cu/ZnO/Al2O3催化剂.N2吸附、X 射线衍射、场发射扫描电子显微镜、程序升温还原、程序升温分解结果表明,改进共沉淀法制备的催化剂前驱体中碱式硝酸铜更易转变为碱式碳酸铜,从而提高了前驱体的稳定性,并使得焙烧后的催化剂具有较大的比表面积...     

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.