Ethylene alkylation

When usiag HF TaF ia a flow system for alkylation of excess ethane with ethylene (ia a 9 1 molar ratio), only / -butane was obtained isobutane was not detectable even by gas chromatography (72). Only direct O -alkylation can account for these results. If the ethyl cation alkylated ethylene, the reaction would proceed through butyl cations, inevitably lea ding also to the formation of isobutane (through /-butyl cation). 

A mixture of C-alkyl-ethylene diamine and di-(C-alkyl)-diethylenetriamine, with an alkyl side chain of 8 to 26 carbon atoms is suitable [ 1876] as a corrosion inhibitor. This product can be further reacted with an alkylating agent or an alkylene oxide [836,837]. 

Alkoxy-l,3-dithia-2-phospholane ( O-Alkyl ethylene dithiophosphate )... 

H.W. Werner et al, Effects of Repeated Exposures of Rats to Vapors of Mono alkyl Ethylene Glycol Ethers , JIndHygToxicol... 

Tphe excellent catalytic activity of lanthanum exchanged faujasite zeo-A lites in reactions involving carbonium ions has been reported previously (1—10). Studies deal with isomerization (o-xylene (1), 1-methy 1-2-ethylbenzene (2)), alkylation (ethylene-benzene (3) propylene-benzene (4), propylene-toluene (5)), and cracking reactions (n-butane (5), n-hexane, n-heptane, ethylbenzene (6), cumene (7, 8, 10)). The catalytic activity of LaY zeolites is equivalent to that of HY zeolites (5 7). The stability of activity for LaY was studied after thermal treatment up to 750° C. However, discrepancies arise in the determination of the optimal temperatures of pretreatment. For the same kind of reaction (alkylation), the activity increases (4), remains constant (5), or decreases (3) with increasing temperatures. These results may be attributed to experimental conditions (5) and to differences in the nature of the active sites involved. Other factors, such as the introduction of cations (11) and rehydration treatments (6), may influence the catalytic activity. Water vapor effects are easily... 

More heavily alkylated ethylene oxides (Kq. 705) have also been subjected to the action of hydrogen halides.761- 18 1,5S-lW Mixtures of isomeric h lohydrins are undoubtedly produced, but precise quantitative data still remains to be aeoured. 

Poly(N-alkyl-ethylene imine) can be prepared by cationic ring-opening polymerization of N-alkylaziridines however, branched polymers are obtained by this way 19>. Linear poly-MEI may be obtained by N-methylation of linear PEI by the Clarke-Eschiweiler variation of the Leukart reaction, in which an excess of formic acid is used together with formaldehyde. The reaction may be performed either on PEI, or... 

Shultz LH, Tempel DJ, Brookhart M, Palladium(II) -Agostic Alkyl Cations and Alkyl Ethylene Complexes Investigation of Polymer Chain Isomerization Mechanisms, J Am Chem Soc, 123, 11539-11555(2001)... 

Alkylation Ethylene oxide Alkylation of amino, carboxyl, hydroxyl and mercapto groups in proteins... 

Benzene alkylation Ethylene (ethanol) Ethylbenzene HMFI/HBEA... 

Detailed studies in model olefins have shown that vinylidene and vinyl compounds are relatively unreactive toward singlet oxygen compared with tri-alkyl ethylenes (36). 

A special type of alkene metathesis is the reaction of an alkene with an alkyne to give a diene. Thus, a reaction between a monoalkylated acetylene and a mono-alkylated ethylene leads to a 1,3-diene bearing a methyhdene and a mixture of (Z)-and ( )-alkene residues [213]. If both unsaturated residues are structurally confined, as in a propargyl-allylamide, cychzation to a vinyl pyrrohne occurs [236]. This reaction has become a useful tool in the generation of sohd support-bound dienes for [2 -i- 4]-cycloadditions [237]. 

Alkyl ethylene oxide condensates and nonionic polymers such as poly(vinyl alcohol) or poly(propylene oxide)-poly(ethylene oxide) block copolymers become insoluble in water above a certain temperature, usually designated as the cloud point. The polymer chains collapse at this temperature, and, consequently, flocculation of aqueous dispersions or emulsions stabilized by these surfactants occurs when the system is heated above the cloud point. 

Let us now consider the situation in tetra(primary-alkyl)ethylenes (Andersen et al., 1985 Olah and Prakash, 1977 Richardson and Gunderson, 1976). Assuming perpendicular conformations of the alkyl groups, there are five different possible combinations as shown in Scheme 8. Yet only one— the Ii. conformer with Dj symmetry—is found in the crystal (R = Ph), in solution (R = i-Pr, t-Bu), and in the gas phase (R = Me, Et, i-Pr, t-Bu, Ph molecular mechanics calculations) (Andersen et al., 1985). 

What factors, then, determine the conformation in these types of molecules It is rather obvious that van der Waals forces dominate, and molecular-mechanics computations on model di(primary-alkyl)ethylenes help to quantify the contributions from different interactions. It turns out that two alkyl groups on the same side of the olefin plane syn) repel each other if they are in c -vicinal or geminal positions relative to each other, but attract each other if they are trans substituted, regardless of the kind... 

It is possible to monitor ethylene chain growth at cationic a-diimine nickel and palladium centers by low-temperature NMR spectroscopy. ° ° Under these conditions, the alkyl ethylene complex on the left of Scheme 2 is the catalyst resting state. (This is... 

Initially, chain transfer was proposed to occur via associative displacement of the unsaturated polymer chain from an olefin hydride intermediate by monomer (Scheme 3A). The bulky ortho substituents were proposed to block axial approach of monomer and retard the rate of displacement. Alkyl ethylene model systems established that indeed exchange of... 

Other alkylaromatics synthesis processes are also of interest. The H-ZSM-5 zeohte is used industrially to selectively alkylate ethylene on toluene into paraethyl-toluene, which is an intermediate for production of the monomer paramethylstyrene. The selective synthesis of paracymene was considered by selective alkylation of propylene on toluene with the H-ZSM-5 zeolite. Open zeolites (e.g., Y) are catalysts of potential interest for the alkylation of benzene by C10-C15 linear olefins, which produce linear alkylbenzenes (LABs) used in manufacturing detergents. Good selectivities for 2.6-dialkylnaph-thalene (alkyl=methyl or isopropyl) can be obtained by alkylation of naphthalene by methanol, propylene, or isopropanol on H-mordenite. 

Stupp and coworkers first prepared mesostructured sulfides with oligomeric alkyl ethylene oxides [89, 90]. Lyotropic surfactant liquid-crystal phases are generated with the addition of appropriate metal ions, for example, Cd +. Hydrogen sulfide or hydrogen selenide gas is then fed into the solution to solidify the mesostructured organic-inorganic composites. The difficulty in this process remains the removal of the surfactants. A family of mesostructured solids, such as CdS, ZnS, and CdSe, have been successfully synthesized. 

The selected NMR spectra of these synthesized lithium alkyl ethylene dicarbonate and lithium alkyl propylene dicarbonate are shown in Fig. 5.7. 

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