Chloro-2,4,4-trimethylpentane

The synthesis and purification of cumyl alcohol (CumOH), p-dicumyl methyl ether (DCE)) and 2-chloro-2,4,4-trimethylpentane (TMPC1), and the sources and purification of methyl chloride (MeCl), methylcyclohexane (MCHx), isobutylene have been described [9, 10]. P-Pinene (P-PIN), (Aldrich), was chromatographed over alumina (activity I, Fisher), and freshly distilled over CaH2 under nitrogen according to 1H-NMR spectroscopy and GC analysis the purity was >99%. 2,6-Di-/er/-butylpyridine (DtBP), (Aldrich), anhydrous A,A-dimethylacetamid (DMA), (Aldrich), ethylaluminum dichloride (EtAlCl2), 1.0 M solution in hexanes (Aldrich), and methanol (Fisher) were used as received. 

Postpolymerization of difunctional monomers to effect star branching has been successfully applied in cationic polymerization, e.g. in the case of polyisobutylene initiated with 2-chloro-2,4,4,-trimethylpentane/TiCl4. Addition of divinylbenzene leads to star polymers [104], Vinyl ethers, when polymerized with HI/ZnI2 in toluene at — 40°C, can be copolymerized with divinylether... 

Problem 4.32 Give topological structural formulas for (a) propane, (h) butane, (c) isobutane, (d) 2,2-dimethylpropane, (e) 2,3-dimethylbutane, (/), 3-ethylpentane, (g) l-chloro-3-methylbutane, (h) 2,3-dichloro-2-methylpentane, (/) 2-chloro-2,4,4-trimethylpentane. -4... 

Catalyst systems with improved heat transfer capability for the production of PIB polymers in continuous slurry polymerization processes have been described. The catalyst consists of a Lewis acid, including Friedel-Crafts catalysts such as AICI3, and a tertiary halide containing compound, e.g., 2-chloro-2,4,4-trimethylpentane or ethylaluminum dichloride (12,13). 

H. Schlaad, K. Erentova, R. Faust, B. Charleux, M. Moreau, J.-P. Vairon, and H. Mayr, Kinetic study on the capping reaction of living polyisobutylene with 1,1-diphenylethylene. 1. Effect of temperature and comparison to the model compound 2-chloro-2,4,4-trimethylpentane, Macromolecules, 31(23) 8058-8062, November 1998. 

Exercise 13-16 Devise a synthesis of 2-chloro-2,4,4-trimethylpentane from organic compounds with four carbons or less and any necessary inorganic reagents. Your synthesis should involve the C-C bond-forming reactions listed in Table 13-4 and other reactions shown in Table 13-5. The product should be 2-chloro-2,4,4-trimethyl-pentane and not a mixture of its isomers. 

T [Tick] free Tm TMPCl TPE o Glass transition temperature Concentration of free and uncomplexed TiCl4 Melting temperature 2-Chloro-2,4,4-trimethylpentane Thermoplastic elastomer Tensile strength... 

The first synthesis of multiarm star polyisobutylene (PIB), with DPn(arm)=116 and the average number of arms=56, was described by Marsalko et al. [6]. The procedure started with the living polymerization of IB by the 2-chloro-2,4,4-trimethylpentane (TMPCl)/TiCl4 initiating system in CH2Cl2/hexane (50/50 v/v) at -40 °C in the presence of triethylamine. At 95% IB conversion, divinylben-zene (DVB, 6, containing 20% ethyl vinylbenzene) was added to effect linking at r=[DVB]/[TMPCl] = 10. 

Using 2-chloro-2,4,4,-trimethylpentane as the initiator and ethylaluminum dichloride as the Lewis acid, McDonald [5] and Shaffer [6] prepared high molecular weight polyisobutylene with perfluorinated alkanes as polymerization solvents. 

The rates of initiation and propagation are comparable when the covalent initiator and dormant chain ends have similar structures. Therefore, 1-phenylethyl precursors are useful initiators for styrene polymerizations, but are poor initiators for a-methylstyrene and vinyl ether polymerizations. Similarly, cumyl derivatives are good initiators for isobutene and styrene, but are poor initiators for vinyl ethers their initiation of a -methylstyrene is apparently slow [165]. 1-Alkoxyethyl derivatives are successful initiators for vinyl ethers, styrenes, and presumably isobutene polymerizations [165,192]. /-Butyl derivatives initiate polymerization of isobutene slowly [105]. This is mirrored in model studies that show that /-butyl chloride undergoes solvolysis approximately 30 times slower than 2-chloro-2,4,4-trimethylpentane [193]. This may be due to insufficient B-strain in monomeric tertiary precursors [194]. In contrast, monomeric and dimeric or polymeric structures of secondary esters and halides apparently have similar reactivity. 

Supercritical carbon dioxide can be used as a solvent in the BF3 — Et20-catalyzed alkylation of phenols. Under these conditions phenol reacts with 2-chloro-2,4, 4-trimethylpentane and poly(isobutylene)-Cl (PIB-Cl) to give the corresponding para-alkylated phenols (equations 24 and 25) °. 

Experiments were carried out with IB and St, arguably the two most important representative olefins polymerizable by cationic means. Polymerizations were initiated by the purposely added initiator 2-chloro-2,4,4-trimethylpentane (TMPC1) or by adventitious moisture, H20 (i.e absence of purposely added initiator), in conjunction with Ti l4 under various conditions specified in the legends to the figures and tables. The raw data are collected in tables shown in the Appendix. This section concerns the presentation of the data and their interpretation in terms of the model developed in Sect 2. 

Chloro-4-(trifluoromethyl)benzene 3-Chloro-1,1,1-trifluoropropane 2-Chloro-2,4,4-trimethylpentane Chlorotrimethylstannane 2-Chloro-1,3,5-trinitrobenzene Chlorotrinitromethane Chlorotriphenylmethane... 

The first hint toward a living cationic polymerization of isobutene was provided by Nuyken and coworkers in 1982 when they reported that the cationic polymerization of isobutene could be initiated by 2-chloro-2,4,4-trimethylpentane (Scheme 8.6), which is a low molecular weight analog of the covalent chloride-terminated PIB, in a polar solvent at —85°C [26]. This work indicated that the irreversible termination reaction in the inifer polymerization mechanism could become reversible in a more polar medium, which was indeed demonstrated by Kennedy who... 

Scheme 8.6 Structures of (a) 2-chloro-2,4,4-trimethylpentane, (b) cumyl esters, and (c) cumyl ethers used as initiators for the cationic polymerization of isobutene.

The living carbocationic polymerization of styrene was reported by Kennedy using 2-chloro-2,4,4-trimethylpentane (TMPCl) with TiCl4 as initiating system in the presence of various electron donors, such as At,At-dimethylacetamide... 

Initiating system 2-Chloro-2/4/4-trimethylpentane (TMPCIl/riCU + dimethylacetamide (DMA) (electron donor) + 2,6-d/-t-butylpyridine (DtBP) (proton trap)... 

Indene 2-chloro-2,4,4-trimethylpentane + T1CI4 Methyl chloride/ CH3-cyclohexane -80... 

RAFT polymerization of MMA or St with PIB-CTA as the RAFT agent. [Note TMPCl = 2-chloro-2,4,4-trimethylpentane DCC = //.// -dicyclohexylcarbodiimide DMAP = 4-(dimethylamino) pyridine CTA = 4-cyano-4-(dodecyl sulfanyl thiocarbonyl sulfanyl) pentanoic add.]... 

It is also clear that intramolecular strain (sometimes called back strain or B-strain ), which results from steric repulsion between groups attached to the carbon bearing the leaving substituent, also plays an important role in accelerating the reaction of haloalkenes. Such ground-state destabilization is, for example, used to account for the observations that, under the same conditions, 2-chloro-2,4,4-trimethylpentane undergoes solvolysis about 20 times faster than 2-chloro-2-methylpropane and 4-chloro-2,2,4,6,6-pentamethylheptane is nearly 500 times faster (Table 7.3) ... 

The stmcture of the initiator influences the initiation step by affecting the rate of ionization and cationation. Ionization is fester and cationation is slower for the more stable cation. It is important to note that back strain, that is, the release of steric strain upon ionization, may contribute significantly to the ease of ionization. Due to the absence of back strain, ttrt-butyl chloride and cumyl chloride are inefficient initiators for the polymerization of IB and aMeSt, respectively. In contrast, the corresponding dimeric chlorides (2-chloro-2,4,4-trimethylpentane (TMPCl) and 2-chloro-2,4-diphenyl-4-methylpentane ) are excellent initiators. 

The carbocationic polymerization of ND proceeds with transannular rearrangement, where both double bonds are involved. Thus, a product polymer has a rigid and high-Tg ( 320 °C) tricyclic repeat stmcture, suitable for thermoplastic applications. Peetz et al. examined cationic polymerization of ND using the 2-chloro-2,4,4-trimethylpentane (TMP-Cl)/TiCl4 initiating system. The use of a proton trap or an added base at -35 to -60 °C rendered the reaction controlled, and the inaeased linearly with conversion up to approximately 45%. The produrt polymer chain consisted of approximately equal amounts of exo/exo and exo/endo connected tricyclic repeat units. Furthermore, a set of three-arm star block copolymers, t-cumyl(PIB- -PND)3 and t-cumyl (PND-b-PIB)3, were prepared and characterized. ... 

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