Oligomeric control

Nicolaides, C. P., Scurrell, M. S. and Semano, P. M. Nickel silica-alumina catalysts for ethene oligomerization - control of the selectivity to 1-alkene products. Appl. Catal., A, 2003, 245, 43-53. 

Scheme 8-2 Oligomerization control via template-bound monomers. I =radical initiator, T-1 = chain transfer agent.

Scheme 8-3 Oligomerization control via template-bound initiator and terminator. I = radical initiator, T = radical terminator.

Boularan, C., Scott, M. G., Bouroug3a, K., Belial, M., Esteve, E., Thuret, A., et al. (2007). Beta-arrestin 2 oligomerization controls the Mdm2-dependent inhibition of p53. Proceedings of the National Academy of Sciences of the United States of America, 104(46), 18061-18066. 

Development of Novel Activated Carbon for Oligomerization Control.450... 

Calamai M, Specht CG, Heller J et al (2009) Gephyrin oligomerization controls GlyR mobility and synaptic clustering. J Neurosci 29 7639-7648... 

The addition of alcohols to form the 3-alkoxypropionates is readily carried out with strongly basic catalyst (25). If the alcohol groups are different, ester interchange gives a mixture of products. Anionic polymerization to oligomeric acrylate esters can be obtained with appropriate control of reaction conditions. The 3-aIkoxypropionates can be cleaved in the presence of acid catalysts to generate acrylates (26). Development of transition-metal catalysts for carbonylation of olefins provides routes to both 3-aIkoxypropionates and 3-acryl-oxypropionates (27,28). Hence these are potential intermediates to acrylates from ethylene and carbon monoxide. 

The mechanistic steps are as follows paraffins dehydrogenate to olefins the olefins oligomerize and cyclize and the cycHcs aromatize. Because the first step is rate controlling, very Httie olefin is actually present. The BTX product is relatively free of nonaromatics and therefore is very desirable as a chemical feed. As in reforming, some C —C2 fuel gas is produced along with a valuable hydrogen stream. Prom a C —feed the BTX product is roughly 35 45 20, respectively. 

Feldman et a .210 211 and Wulff et ul v have examined other forms of template controlled oligomerization of acrylic monomers. The template (23) has initiator and transfer agent groups attached to a rigid template of precisely defined structure.210 "11 Polymerization of MMA in the presence of 23 gave a 3 unit oligo(MMA) as ca 66% of the polymeric product. The stereochemistry of the oligomer was reported to be different" from that of atactic PMMA. 

AB and difunctional oligomers leading to ABA types of structures. The molecular weight control of the growing segments is achieved by the ratio of the cyclic monomer to the oligomeric initiator in the original reaction mixture. 

In the early 1990s, Moore et al. reported the syntheses of a tremendous variety of meffl-connected PAMs [5 b, 36]. They recognized that the structural rigidity of systems like 8 could be useful in supramolecular chemistry. The convergent, stepwise approach of linear oligomeric phenylacetylene sequences developed in the Moore laboratory permitted absolute control over chain length, order of... 

In order to enhance the stability of hposomes and to provide a biocompatible outermost surface shucture for controlled immobihzation (see Section IV), isolated monomeric and oligomeric S-layer protein from B. coagulans E38/vl [118,123,143], B. sphaericus CCM 2177, and the SbsB from B. stearothermophilus PV72/p2 [119] have been crystallized into the respective lattice type on positively charged liposomes composed of DPPC, HD A, and cholesterol. Such S-layer-coated hposomes are spherical biomimetic structures (Fig. 18) that resemble archaeal ceUs (Fig. 14) or virus envelopes. The crystallization of S-... 

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