四价钼催化体系合成高乙烯基聚丁二烯的研究

<正> 五价钼催化体系用于1,2-聚丁二烯的合成已有较多的报道。本工作在以前研究结果的基础上,对四价钼体系催化丁二烯的聚合规律进行了初步研究。 聚合操作在严格的除氧和去水的气氛下进行,聚合产物的分析同前报,除特殊指明者外,聚合条件均为Mo/Bd=2.0×10_-4(摩尔比),50℃,聚合7小时。     

A STUDY OF POLYBUTADIENE SYNTHESIS WITH MoCl_n(OR)_(4-n)-(i-Bu)_2AlOPh AS A CATALYST

The catalytic effect of Mo Cl_n (OR)_(4_n)-(i-Bu)_2AlOPh on the polymerization of butadiene inhydrogenated gasoline is studied (R is alkyl, cycloheptyl, phenyl of C_(4_16)). In this system, the solu-bility and the catalytic activity of the catalyst do not depend on whether the number of carbon atomsin R group is odd or even. The R group with the primary and secondary carbon atom has a fairlygreat influence on the catalytic activity. When R is an alkyl, the catalytic activity increases and therange of Al/Mo values that keeps higher conversion of butadiene is broadened as the size of the Rgroup increases. The content of 1,2-units in the polymer hardly varies with the size of the R group.     

二异丁基锌控制高密度聚乙烯分子量的研究

本文报告了TiCl_4-MgCl_2-AlCl_3/Al(i-Bu)_3-Zn(i-Bu)_2催化体系的乙烯聚合反应中,二异丁基锌对产物分子量和聚合活性的影响。结果表明:在适宜的聚合条件下,二异丁基锌可以有效地控制产物的分子量。     

MoCl_n(OR)_(4_n)-(i-Bu)_2AlOPh 体系催化合成1,2-聚丁二烯的研究

<正> 在前报中,报道了用MoCl_n(OC_8H_17)_(4_a)-(i-Bu)_2AlOPh 催化体系合成1,2-聚丁二烯的工作,发现 MoC_n(OC-8H_17)_(4_n) 在加氢汽油中的溶解性高于MoCl_4~[2],且催化活性也有提高。本文在以前工作基础上,选用不同的OR基团,研究了MoCl_(OR)_(4_n)在加氢汽油中的溶解性及其催化行为与R基的关系,探讨了主、助催化剂用量及配比对聚合活     

水溶性热塑性结晶高聚物聚环氧乙烷的合成及其性能的研究

环氧乙烷于双金属氧联醇盐或i-Bu_3Al-H_3PO_4-H_2O-二甲基苯胺(DMA)四元催化剂作用下在甲苯中呈均相聚合。二种催化剂均显示出高度活性,但前一体系的聚合速度较后一体系平缓。产物分子量可高达一百万。如用石油醇醚为溶剂,则转化率及分子量均下降。四元催化剂的最佳组成比为i-Bu_3Al:H_3PO_4:H_2O:DMA=1:0.17:0.17:0.10。产物溶于水并能模压成型。扯断强度随分子量增加而增加,可达100公斤/厘米~2。     

THE POLYMERIZATION OF EPICHLOROHYDRIN WITH Nd(i-oPr)_3-Al(i-Bu)_3 SYSTEM

Epichlorohydrin (ECH) was polymerized with a rare earth catalytic system: Nd (i-OPr)_3-Al (i-Bu)_3. The effects of Al/Nd molar ratio, solvents, the polymerization time and temperature,the aging time and temperature of the catalyst preparation were studied. The results showed thatat a low Al/Nd molar ratio (4) of the Nd(i-OPr)_3-Al(i-Bu)_3 system ECH polymerized at a lowtemperature (248K) with a high conversion. The average molecular weight ofpolyepichlorohydrin (PECH) ranged from 1×10~5 to 3×10~5.     

Preparation and Properties of Polyallenes. I. Polymerization of Allene by Ziegler-Type Catalysts

The polymerization of allene induced by organoaluminum-vanadium oxytrichloride catalysts has been investigated in aliphatic hydrocarbons and at normal pressure. For the catalysts investigated, the polymerization activity decreases at decreasing order of alkylation of the aluminum alkyl: AIR₃ > AIR₂X > AIRX₂ (R is Et or i-Bu; X is halogen). Compared with other aluminum trialkyls, trimethylaluminum shows a low activity. For the Al-i-Bu₃-VOCl₃ system, the effects of catalyst ratio, reaction time, and temperature have been studied.     

MoO_2Br_2体系催化丁二烯聚合中烯丙基卤素的作用

ＭｏＯ２Ｂｒ２－Ａｌ（ｉ－Ｂｕ）２ＯＰｈＣＨ３（－ｍ）体系催化丁二烯１，２－聚合过程中添加Ｃ３Ｈ５Ｘ（Ｘ＝Ｃｌ、Ｂｒ和Ｉ）对聚合物分子量有较好的调节作用，其中以Ｃ３Ｈ５Ｂｒ的调节作用最强，Ｍｎ从１７．５×１０５降至３．５×１０５，但对催化活性有一定的影响．在测定催化体系的ＵＶ光谱、（１３）Ｃ－ＮＭＲ谱、聚合活性和聚合动力学参数的基础上，讨论了Ｃ３Ｈ５Ｘ在催化体系中的行为．     

BF_3·OEt_2对钼体系催化合成1,2-聚丁二烯的影响

在以加氢汽油为溶剂,MoCl_3(C_7H_(15)COO)_2(Mo)为主催化剂,(i-Bu)_2AlO〈O〉(Al)为助催化剂合成1,2-聚丁二烯的二元催化体系中,添加BF_3CH3·OEt_2等,对体系的催化活性影响显著。以的混合物为第三组份加入催化体系,较大幅度提高了钼系催化体系的活性。在Mo/Bd=8.0×10~(-5)(摩尔比),聚合5小时,丁二烯转化率可达到70％。初步搞清了钼催化体系合成的1,2-聚丁二烯中产生凝胶的条件,推测了凝胶的生成原因,考察了聚合条件对催化活性、分子量及微观结构含量的影响。     

Vinyl addition polymerization of norbornene using cyclopentadienylzirconium trichloride activated by isobutyl‐modified methylaluminoxane

Norbornene polymerization using the commercially available and inexpensive catalyst system, cyclopentadienylzirconium trichloride (CpZrCl₃) and isobutyl‐modified methylaluminoxane (MMAO), were carried out over a wide range of polymerization temperatures and monomer concentrations. For the CpZrCl₃ catalyst system activated by aluminoxane with a 40 mol % methyl group and a 60 mol % isobutyl group (MMAO_40/60), the polymerization temperature and monomer concentration significantly affected the molecular weight (M_n) of the obtained polymer and the catalytic activity. With an increase in the polymerization temperature from 0 to 27 °C, the catalytic activity and M_n increased, but these values dramatically decreased with the increasing polymerization temperature from 27 to 70 °C, meaning that the most suitable temperature was 27 °C. The CpZrCl₃/MMAO_40/60 ([Al]/[Zr] = 1000) catalyst system with the [NB] of 2.76 mol L^?1 at 27 °C showed the highest activity of 145 kg mol_Zr^?1 h^?1 and molecular weight of 211,000 g mol^?1. The polymerization using the CpZrCl₃/MMAO_40/60 catalyst system proceeds through the vinyl addition mechanism to produce atactic polynorbornene, which was soluble in chloroform, toluene, and 1,2‐dichlorobenzene, but insoluble in methanol. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1185–1191, 2008     

Polymerization and copolymerization of α-alkylacrylic acids and characterization of their polymers

α-Alkylacrylic acids (RAA's) bearing n-alkyl groups were found to homopolymerize with slower rates than acrylic and methacrylic acids to number-average molecular, weight (M?_n) of 10⁴ or above. When the α-substituent was a branched alkyl group, the polymerization rate and M?_n decreased further. Reactivities of RAA's in copolymerization were interpreted by steric and resonance effects of the alkyl group using Hancock's steric substituent constant. Comparison of the reactivities of RAA's with those of methyl α-alkylacrylates revealed that replacement with the smaller carboxyl group facilitates polymerization and copolymerization. Preference of co-syndiotactic propagation in the copolymerization of methacrylic acid with styrene changed to random fashion in the copolymerization of the α-higher alkyl derivatives. After methylation with diazomethane, the homopolymers were shown to be thermally less stable than poly(methyl methacrylate). T_g's of poly(methyl α-ethylacrylate) and poly(methyl α-n-propylacrylate) were 57 and 25°C, respectively.     

Copolymerization of butadiene and styrene with neodymium naphthenate based catalyst

Copolymerization of butadiene (Bd) and styrene (St) was carried out in toluene at 50 °C by a conventional rare earth catalytic system, Nd(naph)₃-Al(i-Bu)₃-Al(i-Bu)₂Cl. It exhibited a high catalytic activity and high stereospecificity in the copolymerization. The influences of the conditions in polymerization on the yield, composition, microstructure and molecular weight of copolymer were thoroughly studied. According to the 13C-NMR spectrum, the resultant copolymer containing 18% St units, and the diad fraction of St-trans Bd or St-vinyl Bd can hardly be found in its 13C-NMR. The cis-1,4 content of Bd unit of the copolymer decreased little with the increase of St content. The GPC curves indicate the presence of two kinds of active sites in the polymerization.     

Polymerization of isoprene with η5‐C5H4(tert‐Bu)TiCl3/MAO catalyst

cis‐Selective polymerizations of isoprene with the catalysts composed of η⁵‐C₅H₄(R)TiCl₃ (1; R?H, 2 ; tert‐Bu) and methylaluminoxane were investigated. Both catalysts showed remarkable catalytic activities for the polymerization of isoprene. The polymerization activities were strongly affected by the substituent introduced on cyclopentadienyl ring. Introduction of bulky tert‐butyl group was found to be effective for enhancement of polymerization activity, but the cis‐content of polyisoprene prepared by the 2 /MAO catalyst was lower than that by 1 /MAO catalyst. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1841–1844, 2004     

钼体系催化丁二烯聚合反应催化剂相态的研究

钼体系催化丁二烯聚合反应催化剂相态的研究夏少武，夏树伟，赵菁，张平（青岛化工学院应化系，青岛，２６６０４２）关键词胶体催化剂，Ｔｙｎｄａｌｌ效应，陈化ＭｏＣｌ３（ＯＣ８Ｈ１７）２～（ｉ－Ｂｕ）２ＡＩＯＰｈＣＨ３（间）体系在加氢汽油溶液中具有较高的催化...     

Controlled radical polymerization of alkyl acrylates and styrene using a half-sandwich molybdenum(III) complex containing diazadiene ligands

The half-sandwich molybdenum(III) complex CpMoCl₂(ⁱPr₂-dad) (ⁱPr₂-dad=ⁱPr-NCH-CHN-ⁱPr) proved to be an effective metal catalyst for the controlled radical polymerization of methyl acrylate, butyl acrylate, and styrene. In conjunction with an alkyl iodide [R-I: CH₃CH(COOEt)I] as an initiator and in the presence or absence of Al(O-i-Pr)₃ as a co-catalyst, the molybdenum-based system gave polymers with narrow molecular weight distributions. The in situ addition of styrene to a macroinitiator of poly(methylacrylate) afforded an AB-type block copolymer.     

Acyclic diene metathesis polymerization of 2,5‐dialkyl‐1,4‐divinylbenzene with molybdenum or ruthenium catalysts: Factors affecting the precise synthesis of defect‐free,high‐molecular‐weight trans‐poly(p‐phenylene vinylene)s

Factors affecting the syntheses of high‐molecular‐weight poly(2,5‐dialkyl‐1,4‐phenylene vinylene) by the acyclic diene metathesis polymerization of 2,5‐dialkyl‐1,4‐divinylbenzenes [alkyl = n‐octyl ( 2 ) and 2‐ethylhexyl ( 3 )] with a molybdenum or ruthenium catalyst were explored. The polymerizations of 2 by Mo(N‐2,6‐Me₂C₆H₃) (CHMe₂ Ph)[OCMe(CF₃)₂]₂ at 25 °C was completed with both a high initial monomer concentration and reduced pressure, affording poly(p‐phenylene vinylene)s with low polydispersity index values (number‐average molecular weight = 3.3–3.65 × 10³ by gel permeation chromatography vs polystyrene standards, weight‐average molecular weight/number‐average molecular weight = 1.1–1.2), but the polymerization of 3 was not completed under the same conditions. The synthesis of structurally regular (all‐trans), defect‐free, high‐molecular‐weight 2‐ethylhexyl substituted poly(p‐phenylene vinylene)s [poly 3 ; degree of monomer repeating unit (DP_n) = ca. 16–70 by ¹H NMR] with unimodal molecular weight distributions (number‐average molecular weight = 8.30–36.3 × 10³ by gel permeation chromatography, weight‐average molecular weight/number‐average molecular weight = 1.6–2.1) and with defined polymer chain ends (as a vinyl group, ? CH?CH₂) was achieved when Ru(CHPh)(Cl)₂(IMesH₂)(PCy₃) or Ru(CH‐2‐OⁱPr‐C₆H₄)(Cl)₂(IMesH₂) [IMesH₂ = 1,3‐bis(2,4,6‐trimethylphenyl)‐2‐imidazolidinylidene] was employed as a catalyst at 50 °C. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6166–6177, 2005     

钼体系催化丁二烯聚合动力学——链转移

本文考察了MoCl_4OC_8H_(17)-(i-Bu)_2Alo催化体系在加氢汽油中催化丁二烯聚合过程中的链转移情况,提出了比较聚合体系中各组分对链转移的贡献大小的方法和计算链转移次数的公式及链转移次数与聚合温度的函数关系式。发现本体系中单体和主催化剂是主要的链转移剂,向烷基铝的链转移占10％,向杂质的链转移仅占6％。在链转移反应中,单体和主催化剂的级数为1,烷基铝的级数为1/2。     

Preparation of ultra high molecular weight amorphous poly(1‐hexene) by a Ziegler–Natta catalyst

High molecular weight polymers such as poly (α‐olefin)s play a key role as drag‐reducing agents which are commonly used in pipeline industry. Heterogeneous Ziegler–Natta catalyst system of MgCl₂.nEtOH/TiCl₄/donor was prepared using a spherical MgCl₂ support and utilized in synthesis of poly(1‐hexene)s with a viscosity average molecular weight (M_v) up to 3.5 × 10³ kDa. The influence of effective parameters including Al/Ti ratio, polymerization temperature, monomer concentration, effect of alkylaluminus type on the productivity, and molecular weight of the products was evaluated. It was suggested that the reactivity of the Al‐R group and the bulkiness of the cocatalyst were correlated to the performance of the Ziegler–Natta catalyst at different polymerization time and temperatures, affecting the catalyst activity and M_v of polymers. Moreover, bulk polymerization method leads to higher viscosity average molecular weights, revealing the remarkable effect of polymerization method on the chain microstructure. Fourier transform infrared, ¹³C Nuclear magnetic resonance spectra, and DSC thermogram of the prepared polymers confirmed the formation of poly(1‐hexene). The properties of the polymers measured by vortex test showed that these polymers could be used as a drag‐reducing agent. Drag‐reducing behaviors of the polymers exhibited a dependence on the M_v of the obtained polymers that was changed by variation in polymerization parameters. Copyright © 2016 John Wiley & Sons, Ltd.     

Addition polymerization of norbornene using bis(β‐ketoamino)nickel(II)/tris(pentafluorophenyl)borane catalytic systems

Norbornene polymerizations proceeded in toluene with bis(β‐ketoamino)nickel(II) {Ni[CH₃C(O)CHC(NR)CH₃]₂ [R = phenyl ( 1 ) or naphthyl ( 2 )]} complexes as the catalyst precursors and the organo‐Lewis compound tris(pentafluorophenyl)borane [B(C₆F₅)₃] as a unique cocatalyst. The polymerization conditions, such as the cocatalyst/catalyst ratio (B/Ni), catalyst concentration, monomer/catalyst ratio (norbornene/Ni), polymerization temperature, and polymerization time, were studied in detail. Both bis(β‐ketoamino)nickel(II)/B(C₆F₅)₃ catalytic systems showed noticeably high conversions and activities. The polymerization activities were up to 3.64 × 10⁷ g of polymer/mol of Ni h for complex 1 /(B(C₆F₅)₃ and 3.80 × 10⁷ g of polymer/mol of Ni h for complex 2 /B(C₆F₅)₃, and very high conversions of 90–95% were maintained; both polymerizations provided high‐molecular‐weight polynorbornenes with molecular weight distributions (weight‐average molecular weight/number‐average molecular weight) of 2.5–3.0. The achieved polynorbornenes were confirmed to be vinyl‐addition and atactic polymers through the analysis of Fourier transform infrared, ¹H NMR, and ¹³C NMR spectra, and the thermogravimetric analysis results showed that the polynorbornenes exhibited good thermal stability (decomposition temperature > 410 °C). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4733–4743, 2007     

Controlled ring‐opening polymerization of propylene oxide catalyzed by double metal‐cyanide complex

A double metal‐cyanide catalyst based on Zn₃[Co(CN)₆]₂ was prepared. This catalyst is very effective for the ring‐opening polymerization of propylene oxide. Polyether polyols of moderate molecular weight having low unsaturation (<0.015 meq/g) can be prepared under mild conditions. The molecular weight of polymer is entirely controlled by a reacted monomer‐to‐initiator ratio. The polymers prepared with stepwise addition of monomer exhibit a narrower molecular weight distribution as compared with those prepared with one‐step addition of monomer. Various compounds containing active hydrogen, except basic compounds and low‐carbon carboxylic acid, may be used as initiators. The reaction rate increases with increasing catalyst amount and decreases with rising initiator concentration. Polymerization involves a rapid exchange reaction between the active species and the dormant species. It was also proven that, to a certain extent, the chain termination of this catalytic system is reversible or temporary. ¹³C NMR analysis showed that the polymer has a random distribution of the configurational sequences and head‐to‐tail regiosequence. It is assumed that the polymerization proceeds via a cationic coordination mechanism. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1142–1150, 2002