Synthesis of 1-Octene Oligomer by Rare Earth Coordination Catalyst

The polymerization of 1-octene with Nd(P_(204))_3-AlEt_3 catalyst has been successfully carried out for the first time.Some features of polymerization of 1-octene are described.The 1-octene oligomer prepared has an average molecular weight of about 10~3 with molecular weight distribution of about 2.It has a terminal double bond,which can be transferred into terminal carboxy group by direct oxidation with KMnO_4 in acidic solution, and then can be esterified with polyglycol.

COPOLYMERIZATION OF ETHYLENE WITH 1-OCTENE USING Et(Ind)_2ZrCl_2/MAO CATALYST

Copolymerization of ethylene/1-octene was carried out in toluene withvarious concentrations of comonomer in the feed using Et(Ind)_2ZrCl_2/MAO (methyl alu-minoxane) as catalyst. It was found that with the increase of 1-octene concentration in thefeed the content of 1-octene in the copolymer increases, while the density, melting point,crystallinity and intrinsic viscosity of copolymer decrease. A copolymer with very lowdensity, containing 11.5 mol% of 1-octene (VLLDPE) can be produced with this catalystsystem. The effect of temperature and zirconium aluminum mole ratio of the catalyst onthe copolymerization was also investigated. The results of ^(13)C NMR determination of thecopolymer showed that the 1-octene units in the copolymer are principally isolated.

COPOLYMERIZATION OF 1-OCTENE WITH STYRENE BY RARE EARTH COORDINATION CATALYSTS

The copolymerization of l-octene with styrene catalyzed by rare earth coordination catalysts has been studied for the first time. Some features and kinetic behavior are described. The overall activation energy of the copolymerization was 22.2 KJ/mol and the copolymerization rate could be expressed as R_p=K_p [Nd] [M]~2. (=1.68×10^(-3) L^2/mol^2. S, 50℃, [Oct]/[St]=1). The catalytic activity of various rare earth elements in Ln (naph)_3 for the copolymerization was compared and shows the following sequence: Dy, Y, Yb>Ho>Sm, Gd, Nd>Pr>Ce>La>Tm. Both monomers of l-octene and styrene in the copolymerization by Nd (naph)_3-AlEt_3 have the tendency of constant proportion copolymerization. The structure of the copolymers was studied by ~1H-NMR.

Thermoregulated Organic Biphasic Hydrogenation of 1-Octene Catalyzed by Ru/PETPP Complex

Thermoregulated organic biphasic system composed of triethylene glycol monomethyl ether （TGME） and n-heptane was first applied to the hydrogenation of 1-octene. Under the optimal conditions： P（H2）=5.0MPa, T=80℃, t=3h, 1-octene/Ru=1000 （molar ratio）, the yield of n-octane reached up to 99.6%. Furthermore, the simply decanted catalyst could be reused for 10 times without apparent loss of catalytic activity.

STUDY ON THE MECHANISM OF 1-OCTENE ZIEGLER-NATTA POLYMERIZATION BASED ON THE NUMBER OF ACTIVE CENTERS

The number of active centers (C_p)-t and k_p-t profiles of Solvay type TiCl_3 - AlR_3 (R=C_2H_5, i-C_4H_9) or Stauffer AA TiCl_3-Al (C_2H_5)_3 catalyzed 1-octene polymerization were determined by using an acetyl chloride quenching method as well as kinetic data. The results show that in the studied systems k_p decreases when C_p increases, indicating the presence of two or more types of different active centers. The C_(p^(-t)) plots of the Solvay TiCl_3-AlR_3 systems show the presence of both stable active centers and unstable centers which decay in the polymerization process. The phenomena are explained based on a model of active center plurality. The increases of C_p in the induction periods are also discussed.

^(13)C-NMR STUDY OF ETHYLENE-1-OCTENE COPOLYMERS

A ^(13)C-NMR method is presented for a quantitative determination of the respective monomercomposition and sequence distributions in ethylene-1-octene copolymers prepared with supportedtitanium/magnesium catalyst. On the basis of the sequence distributions, the ethylene-1-octenecopolymerization mechanism was studied. It was found that the observed sequence distributions inethylene-1-octene copolymers are satisfactorily predicted by the two-site model M/M,in whichthe copolymerization proceeds according to first-order Markovian statistics at the two differentsites.

Hydroformylation of 1-Octene over Nanotubular TiO2-supported Amorphous Co-B Catalysts

TiO2 nanotubes supported amorphous Co-B（Co-B/TNTs） catalyst was prepared via impregnation- chemical reduction procedure. The catalyst was characterized with transmission electron microscopy（TEM）, ammonia temperature-programmed desorption（NH3-TPD）, thermogravimetry-differential thermal analysis（TG-DTA）, Fourier transform infrared spectroscopy（FTIR） and Raman spectroscopy. The effects of temperature and ratio of CO to HE on the hydroformylation of 1-octene were studied. At an optimized reaction temperature（150 ℃） and volume ratio of CO to H2（2：1）, the conversion of 1-octene can reach 97.4% with a selectivity of 23.1% for total aldehydes and n/i-aldehyde molar ratio of 40：60. To obtain higher selectivity for linear aldehydes, Co-B/TNTs modified with triphenylphosphine for the hydroformylation of 1-octene were investigated. When molar ratio of P/Co was 4, the yield of total aldehydes was the highest（31.6%） with a good selectivity for linear product（n/i-aldehyde molar ratio was 70：30）. In recycle use, the Co-B/TNTs catalyst modified with triphenylphosphine could be reused five times without reducing the activity and selectivity obviously. For a comparative study, all the Co-B/TNTs to catalyze the hydroformylation of other olefins exhibited high conversion under the optimized conditions.

POLYMERIZATION OF 1-OCTENE AND DETERMINATION OF MARKHOUWINK CONSTANTS OF POLY(1-OCTENE)

The polymerization of 1-octene initiated by methylalmnoxane （MAO）-activated Ni（II）-based-a-diimine complexes [（2,6-i-Pr）2C6H3-DAB（An）]NiBr2 was investigated. Using this catalyst, poly（1-octene）s with molecular weight between 100 × 10^3 and 400 ×10^3 and polydispersity （Mw/Mn） between 1.3 and 1.5 were synthesized successfully by varying reaction time at room temperature. The poly（1-octene）s were amorphous polymers and could be well soluble in tetrahydrofuran （THF）. After fractional precipitation, poly（1-octene）s with narrow molecular weight distributions （Mw/Mn 〈 1.12） were obtained. Their weight-average molecular weights were measured by gel permeation chromatography （GPC） in conjunction with online model BI-MwA multiangle laser light scattering （MALLS）, and their intrinsic viscosities were measured by Maron＇s single-point method. The k and a values in Mark-Houwink equation [η] = KM^a in THF at 40α were 0.089 mL/g and 0.61 respectively.

Highly Selective Diphoshinoamine/Cr(III) Catalysts for Ethylene Tetramerization

Two novel diphoshinoamine ligands have been synthesized. Combination of Cr（Ⅲ） and methylaluminoxane（MAO） generated active catalytic system which can catalyze tetramerization of ethylene with high catalytic activity up to 2.5×10^6 g/mol Cr.h and high selectivity to produce 1-octene （Cs in products is being 89.80 wt%）.

Preparation and Catalytic Performance of Silica-Supported Cr(acac)_3/PNP for Ethylene Tetramerization

Chromium acetylacetonate and bis(diphenylphosphino)isopropylamine were coordinated in situ and supported on methylaluminoxane-modified silica. The catalyst structure and effects of reaction temperature, reaction pressure and Al/Cr molar ratio on ethylene tetramerization were investigated in detail. Chromium was uniformly and firmly immobilized on the support and could not be leached off by methylaluminoxane. The supported catalyst, upon being activated with methylaluminoxane, exhibited catalytic activity of 1.70×107 g/(mol Cr·h) for ethylene tetramerization to form 1-octene at a reaction temperatures of 80 ℃, a pressure of 2.0 MPa and an Al/Cr molar ratio of 300. The supported catalyst presented a good tolerance to high temperature.

Effects of Al(i-Bu)_3 on Propylene Polymerization and Copolymerization by rac-Me_2Si(Ind)_2ZrCl_2/MAO

The effects of adding Al(i-C_4H_9)_3 (TBA) to rac-Me2Si(Ind)2ZrCl2/ MAO catalyzed propylene-1-octene copolymerization were studied. At TBA /MAO (Al/AI mole ratio) of about 0.6, the polymerization activity was found to be much higher than the system without TBA. Increases of polymer molecular weight and 1-octene content from addition of TBA were also observed.