Telomerization of ethylene

To circumvent the formation of ditelomers and to attempt recycling of the catalysts, the telomerization of polyols was studied in the presence of water using water soluble catalysts such as Pd/TPPTS (TPPTS = tris(m-sulfonato-phenyl) phosphine trisodium salt) [9, 12, 16, 17]. Behr et al. studied the telomerization of ethylene glycol under biphasic conditions. Under such reaction conditions, 80% of mono-telomer are formed and only traces of ditelomer and butadiene dimers are detected (Fig. 4). This is attributed to the solubility of the monomer in the catalyst phase. However, the catalyst is unstable and decomposes rapidly, leading to almost inactive catalyst after three runs. This is due to TPPTS oxidation during the work-up of the reaction and can be avoided by addition of 2.5 equiv. ligand in the solution prior to each run. 

Eberhardt et al. 169 170) found that TMEDA, sparteine or other ditertiary amines enable the telomerization of ethylene with benzene by lithium alkyls to yield molecules of the general formula C6H5(CH2CH2)nH. A valuable compilation has been made of related studies employing polyamine chelated alkali metal compounds87). 

Eberhardt and co-workers (12, 13) found that lithium alkyls are active toward the telomerization of ethylene and benzene when a tert-amine or chelating diamine, such as sparteine or N.N.JV. Af -tetramethylenethy-lenediamine (TMEDA), is used [Eqs. (1)—(3)]. 

Another byproduct of the reaction was a mixture of alkyl chlorides in which the alkyl groups had an even number of carbon atoms. These were obviously formed by telomerization of ethylene and hydrogen chloride 2). 

Carbon dioxide has been object of detailed studies either as anion radical scavenger or as direct electrochemical substrate in organic syntheses. Among the dozens of examples of electroorganic syntheses of mono- and dicarboxylic acids even a telomerization of ethylene with C02 has been reported56,57. The reaction has the following stoichiometry ... 

Ethylenation of n-butyllithium, phenyllithium, and benzylic lithium compounds does not occur at low temperature and ordinary pressure (9). Under more rigorous conditions, telomerization of ethylene in aromatic hydrocarbons proceeds vigorously in the presence of an organolithium compound and an amine. Although n-butyllithium is introduced initially, rapid transmetalation occurs to the more acidic aromatic hydrocarbon (telogen) which subsequently adds to ethylene (taxogen) and initiates the carbanionic polymerization of ethylene. This polymerization proceeds to modest molecular weight, but it is terminated by transmetalation back to the aromatic hydrocarbon which initiates another chain to complete the catalytic cycle. 

The rate of telomerization of ethylene in toluene is, as expected, directly proportional to the RLi-TMEDA concentration at 0.04M to 0.10M (Table IV). Thus solubility of the catalyst is not a limiting factor at these concentration levels. With other amines, the influence of structure and concentration is analogous to that discussed in connection with transmetalation. 

Table VII. Telomerization of Ethylene with Olefinic Telogens ...

Much of the early work with N-chelated organolithium compounds was concerned with polymeric reactions—in particular the telomerization of ethylene onto aromatic hydrocarbons such as benzene and toluene to produce long-chain alkylbenzenes (6,7, 8, 9). 

All the above reactions involve hydrogen—lithium interconversion (metalation). There are a limited amount of data available indicating that N-chelated organolithium intermediates also undergo nucleophilic addition to carbon-carbon double and triple bonds much more readily than does the organolithium reagent alone. Indeed, this enhanced reactivity toward addition reactions is a key factor in the telomerization of ethylene onto aromatic hydrocarbons (6, 7,8,9). 

Fig. 36 Telomerization of ethylene and carbon tetrachloride and its relation to the Kharasch...

Fig. 37 Telomerization of ethylene, propylene, vinylchloride and vinylidenechloride with chloroform, 1,1,1,-trichloroethane and 1,1,1,3-tetrachloropropane [33-36, 61, 62]...

Zhiryukhina NP, Kamyshova AA, ETs C et al (1983) Synthesis of polychloroalkanes with several different chlorine-containing groups. Izv Akad Nauk SSSR Ser Khim 1 152-157 Freidlina RKh, Osipov BN (1971) Telomerization of ethylene with 1, 1, 1, 3-tetrachloropro-pane in the presence of iron pentacarbonyl and isopropyl alcohol. Izv Akad Nauk SSSR Ser Khim 12 2837-2839... 

Asscher M, Levy E, Rosin H et al (1963) Telomerization of ethylene and carbon tetrachloride. Novel initiating system. Ind Eng Chem Prod Res Dev 2(2) 121-126... 

Freidlina RKh, Belyavskii AB (1961) Telomerization of ethylene and carbon tetrachloride or chloroform in the presence of the hexac arbonyls of chromium, molybdenum and tungsten. Izv Akad Nauk SSSR Otd Khim Nauk 1 177-178... 

Nylon 7 and nylon 9 are part of a process developed in Russia to form polyamides for use in fibers. The process starts with telomerization of ethylene. Afree-radical polymerization of ethylene is conducted in the presence of chlorine compounds that act as chain-transferring agents. The reaction is carried out at 120-200 C temperature and400-600 atmospheres pressure. The preferred chain-transferring agents for this reaction are CCI4 and COCh ... 

Polyamide 11 is commercially produced by the polycondensation of 11-amino undecanoic acid, which is obtained from castor oil (see also Chapter 24). The monomer is also obtained by telomerization of ethylene and carbon... 

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