2.4.4- Trimethylpentanal

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. 

TRIMETHYLPENTANAL, 51, 4 TRIMETHYLSILYL AZIDE, 50, 107 Triphenylphosphine-cobalt(II) bromide, catalyst, 53, 30,... 

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... 

ALDEHYDES BY OXIDATION OF TERMINAL OLEFINS WITH CHROMYL CHLORIDE 2,4,4-TRIMETHYLPENTANAL... 

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. 

On the other hand, 1,2-epoxy 2,4,4-trimethylpentane has recently been reported to give only one obJorohydrin on treatment with ethereal... 

Gascon and co-workers developed an analytical method suitable for the determination of 1,2-epoxy-2,4,4-trimethylpentane.<2D The epoxide was heated at 100° in a sealed tube with di-n-butylamine, and the resulting product aoetylated with acetic anhydride. Titration with perchloric arid in aoetie acid containing a suitable indicator gave the amount of tertiary amine formed. 

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. 

Assuming equal reactivity of a single x hydrogen and a single y hydrogen, the ratio of the two isomers is then expected to be 9 6. Since together the two primary chlorides total 65% of the monochloride fraction, there will be 39% l-chloro-2,2,4-trimethylpentane (substitution of Jt) and 26% l-chloro-2,4,4-trimethylpentane (substitution of v). 

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. 

An interesting development of the reaction of (V-phenylmaleimide with azides is the synthesis of a polymer-bound pyrrolo[3,4-6 ]-l,2,3-triazole system, potentially useful as a linkage in block-and graft-copolymers. First, 2-azido-2,4,4-trimethylpentane was successfully reacted with bis(4-maleimidophenyl)methane to yield the bis-adduct (166). This subsequently led to azide-bearing poly(2-methylpropene) being reacted with bis(4-maleimidophenyl)methane to yield a mixture of mono- and bis-adducts <92MAC2495>. 

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. 

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