نتایج جستجو برای: olefin

تعداد نتایج: 2960  

Thermodynamic analysis of the cracking of hexane has been conducted by the Gibbs free energy minimization method and second law analysis of overall reactions. By-products have been divided into three groups of methane, alkynes and aromatics and their possible production paths have been discussed. Effect of operating conditions such as temperature and steam-to-hexane ratio on the cracking perfor...

Journal: Polyolefins Journal 2015

Heterogeneous Ziegler-Natta and homogeneous metallocene catalysts exhibit greatly different active sitenature in olefin polymerization. In our previous study, it was reported that MgCl2-supported titanocenecatalysts can generate both Ziegler-Natta-type and metallocene-type active sites according to the type of activators.The dual active site nature of the supported titanocene catalysts was furt...

2008
Wei Wang

The title compound, [CuBr(C(9)H(9)N(5))](n), prepared by the solvothermal treatment of CuBr with 4-(2-allyl-2H-tetra-zol-5-yl)pyridine, is a new homometallic Cu(I)-olefin coordination polymer in which dinuclear Cu(2)Br(2) units are linked by the organic olefin ligand 4-(2-allyl-2H-tetra-zol-5-yl)pyridine, which acts as a bidentate ligand connecting two neighbouring Cu(2)Br(2) units through the ...

Journal: :Science 2006
Daniel J Arriola Edmund M Carnahan Phillip D Hustad Roger L Kuhlman Timothy T Wenzel

We report a catalytic system that produces olefin block copolymers with alternating semicrystalline and amorphous segments, achieved by varying the ratio of alpha-olefin to ethylene in the two types of blocks. The system uses a chain shuttling agent to transfer growing chains between two distinct catalysts with different monomer selectivities in a single polymerization reactor. The block copoly...

Journal: :Journal of the American Chemical Society 2013
Nicolaas A Vermeulen Olga Karagiaridi Amy A Sarjeant Charlotte L Stern Joseph T Hupp Omar K Farha J Fraser Stoddart

The aromatizing ring-closing metathesis has been shown to take place inside an extended porous framework. Employing a combination of solvent-assisted linker exchange and postsynthesis modification using olefin metathesis, the noninterpenetrated SALEM-14 was formed and converted catalytically into PAH-MOF-1 with polycyclic aromatic hydrocarbon (PAH) pillars. The metal-organic framework in SALEM-...

Journal: :International Journal of Molecular Sciences 2008
Bassie B. Marvey

Sunflower (Helianthus annuus L.) oil remains under-utilised albeit one of the major seed oils produced world-wide. Moreover, the high oleic sunflower varieties make the oil attractive for applications requiring high temperature processes and those targeting the C=C double bond functionality. Herein an overview of the recent developments in olefin metathesis of sunflower-based feedstocks is pres...

Journal: :Beilstein Journal of Organic Chemistry 2007
Wolfgang Maison Marina Büchert Nina Deppermann

BACKGROUND Tandem olefin metathesis sequences are known to be versatile for the generation of natural product scaffolds and have also been used for ring opening of strained carbo- and heterocycles. In this paper we demonstrate the potential of these reactions for the desymmetrization of 7-azabicycloalkenes. RESULTS We have established efficient protocols for the desymmetrization of different ...

2017
Wei Wei Xi-Jie Dai Haining Wang Chenchen Li Xiaobo Yang Chao-Jun Li

Natural availability of carbonyl groups offers reductive carbonyl coupling tremendous synthetic potential for efficient olefin synthesis, yet the catalytic carbonyl cross-coupling remains largely elusive. We report herein such a reaction, mediated by hydrazine under ruthenium(ii) catalysis. This method enables facile and selective cross-couplings of two unsymmetrical carbonyl compounds in eithe...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی شریف 1380

چکیده ندارد.

Journal: :علوم و تکنولوژی پلیمر 0
علی اصغر قریشی مهری اصفهانیان

the separation of olefin/paraffin mixtures is an important process in petrochemical industries, which is traditionally performed by low temperature distillation with a high-energy consumption, or complex extractive distillationand adsorption techniques. membrane separation process is emerging as an alternative for traditional separation processes with respect to low energy and simple operation....

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