Neopentyl chloride

Other Reactions. Primary amyl alcohols can be halogenated to the corresponding chlorides by reaction with hydrogen chloride in hexamethylphosphoramide (87). Neopentyl chloride [753-89-9] is formed without contamination by rearrangement products. A convenient method for preparing / f/-amyl bromide and iodide involves reaction of / f/-amyl alcohol with hydrobromic or hydroiodic acid in the presence of Li or Ca haUde (88). The metal haUdes increase the yields (85 —95%) and product purity. 

Radical chlorination of pentane is a poor way to prepare 1-chloropentane, but radical chlorination of neopentane, (CI- C, is a good way to prepare neopentyl chloride, (CHj CO Cl. Explain. 

Primary, secondary, and tertiary alcohols can be converted to any of the four halides by treatment with the appropriate NaX, KX, or NH4X in polyhydrogen fluoride-pyridine solution." This method is even successful for neopentyl halides. Another reagent that converts neopentyl alcohol to neopentyl chloride, in 95% yield, is PPh3-CCl3CN." ... 

The cross-linking rate of EPR by radiation comes close to that of polypropylene. EPDM terpolymers exhibit an enhanced cross-linking rate, and it increases with the diene content. However, not only the cross-linking rate, but also a greater yield of scissions results from the addition of the third monomer. Cross-linking of EPR can be promoted by the addition of a variety of additives, particularly by those that were found effective in polypropylene. Tetravinyl silane, chlorobenzene, nitrous oxide, allyl acrylate, neopentyl chloride, and N-phenyl maleimide were reported to promote the process. 

Problem 7,23 Explain why neopentyl chloride, (CH,),CCHjCI, a 1° RCI, does not participate in typical 8, 2 reactions. M... 

Cross-linking of EPR can be promoted by the addition of a variety of additives, particularly by those that were found effective in polypropylene. Tetravinyl silane, chlorobenzene, nitrous oxide, allyl acrylate and neopentyl chloride,191192 and biphenyl maleimide177 were reported to promote the process. 

This Grignard reaction is particularly difficult to initiate and depends greatly on the purity of the neopentyl chloride. Commercial neopentyl chloride [Eastern] is stirred over four consecutive portions of concentrated sulfuric acid for a period of 6h each followed by 1 h for the mixture to completely settle before draining off the darkened acid layer. The fourth portion of acid is only slightly colored. The clear neopentyl chloride is washed with water followed by aqueous sodium bicarbonate solution, dried over calcium chloride, then filtered from the drying agent before use. Pure neopentyl chloride distils at 83 to 84 °C and is inert to concentrated sulfuric acid at room temperature. 

The complex nature of alkylation of alkenes is illustrated by the reaction of 1- and 2-chloropropane with ethylene,53 which does not yield the expected isopentyl chloride. Instead, l-chloro-3,3-dimethylpentane is formed by isomerization of the primary product to give fcrf-amyl chloride, which adds to ethylene more readily than do starting propyl halides (Scheme 5.4). The same product is also obtained54 when ethylene reacts with neopentyl chloride in the presence of AICI3. 

Here we further examine the suitability of QM-SCRF methods in two chemical reactions the base-catalysed hydrolysis of methyl acetate in water, and the steric retardation of Sn2 reactions of chloride with ethyl and neopentyl chlorides in water. In the two cases the influence of the solvent is examined by using the MST version of the PCM model (see ref. [85] for a detailed description). 

As a second example, we have determined the influence of solvation on the steric retardation of SN2 reactions of chloride with ethyl and neopentyl chlorides in water, which has recently been studied by Vayner and coworkers [91]. In their study solvent effects were examined by means of QM-MM Monte Carlo simulations as well as with the CPCM model. Solvation causes a large increase in the activation energies of these reactions, but has a very small differential effect on the ethyl and neopentyl substrates. Nevertheless, a quantitative difference was found between the stability of the transition states determined using discrete and continuum treatments of solvation, since the activation free energies for ethyl chloride and neopentyl chloride amount to 23.9 and 30.4kcalmoF1 according to MC-FEP simulations, but to 38.4 and 47.6 kcal moF1 from CPCM computations. 

Table 3.3 Calculated activation free energies for the transition states formed in the SN 2 reaction of chloride anion with ethyl and neopentyl chloride in water determined from MST, CPCM and MC-FEP computations...

Reaction of the diol with p-toluenesulfonyl chloride in pyridine, however, produced the ditosylate in nearly quantitative yield. SN2 displacements by chloride on neopentyl tosylate, which bears certain structural similarities to the ditosylate precursor of CAMPHOS, have been shown to give good yields of neopentyl chloride. However, when l,2,2-trimethyl-l,3-bis(hydroxymethyl)-cyclopentane ditosylate was allowed to react with sodium chloride in hexa-methylphosphoramide, in an attempt to form the dichloride, only N, A -dimethyl-p-toluenesulfonamide was isolated. Reaction of the ditosylate with lithium chloride in ethoxyethanol was exothermic and HC1 was evolved but the dichloride was not isolated. The isolated product contained at least one oleflnic bond. Similarly, in N, TV-dimethylformamide, lithium chloride and the ditosylate gave a product that decomposed on distillation. Faced with such repeated failures, a dihalide route to CAMPHOS was abandoned in favor of a more direct approach reaction of the ditosylate with diphenylphosphide anion. 

Deuteriated neopentyl chloride -a,a-d2was pyrolyzed under maximum inhibition of cyclohexene at 445 °C. 2-Methyl-1-butene-3,3-d2 and 2-methyl-2-butene-3-d were found to be unequivocally the products of a rearrangement process183. Consequently, the reaction mechanism is consistent with involvement of an intimate ion-pair intermediate (equation 94). 

Neopentyl chloride was also decomposed under maximum inhibition of cyclohexene at 424-478 °C with the Arrhenius results of Ea = 258.7 kJmol-1 and log 4(s-1) = 13.78. A preliminary study of neopentyl chloride in the presence of cyclohexene and under a singlepulse shock tube showed, by qualitative analysis, the formation of only the rearrangement products 2-methyl-1 -butene and 2-methyl-2-butene, thus providing further evidence of the unimolecular nature of this elimination. 

Neopentyl chloride (101a) and neophyl chloride (101b) react with Ph2P ions in liquid ammonia forming high yields of the substitution product 102a and 102b (equation 74). 

Hastings, J. M., and S. II. Bauer An Electron Diffraction Investigation of the Structure of Neopentyl Chloride and Silico-Neopentyl Chloride. The Determination of Intensities through the use of a Rotating Sector. J. chem. Physics 18, 13—26 (1950). 

Difficult to initiate inert atmosphere and pure neopentyl chloride needed... 

Neopentyl chloride, (CH3)3CCH2Cl, has no chiral C and therefore no enantiomers. 

Recent experimental studies have indicated that a- or p-substitution may alter the gas-phase substitution reactions in different ways than in solution. Kebarle has determined that the activation barrier for the gas-phase reaction of chloride with alkyl bromides increases as Me (-1.9 kcal mol" ) < Et (-1.3 kcal mol" ) < -Bu (0.0 kcal mol" ) < i-Pr (5.6 kcal mol" ). While a-branching does increase the barrier for the substitution reaction, p-branching appears to lower the barrier. This is even more apparent in the essentially equivalent rates for the reaction of fluoride with ethyl and neopentyl chlorides in the gas phase. Another example is the unexpectedly small difference (1.9 kcal mol" ) in the activation energies for the reactions of chloride with methyl- and ferf-butyl chlororoacetonitriles, which was subsequently expanded to include the ethyl and (-propyl analogs (Table 6A) ... 

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