Cyclopentanes Methylcyclopentane

Cycloparafficin Hydrocarbons Cyclopentane Methylcyclopentane Cyclopentane Methylcyclopentane... 

Miscible in many hydrocarbons including cyclopentane, methylcyclopentane, cyclohexane, hexane, and 2-methylhexane. 

Kay, W.B. Vapor pressures and saturated liquid and vapor densities of cyclopentane, methylcyclopentane, ethylcyclopentane and methylcyclohexane, J. Am. Chem. Soc., 69(6) 1273-1277, 1947. 

Other Cycloalkanes. Hydrogen chloride promoted monoethylation of other cycloparaffins (e.g., cyclopentane, methylcyclopentane and methylcyclohexane) and many paraffins (e.g., propane, isobutane, n -pentane, isopentane, 2,2-dimethylbutane, 2,3-dimethylbutane, n-heptane and 2,2,4-trimethylpentane). 

Cycloalkanes Cyclopentane Methylcyclopentane Cyclohexane Methylcyclohexane Pentylcyclohexane Hexylcyclohexane Heptylcyclohexane Octylcyclohexane Nonylcyclohexane Decylcyclohexane U ndecylcyclohexane Dodecylcyclohexane Tridecylcyclohexane Tetradecylcyclohexane Pentadecylcyclohexane Hexadecylcyclohexane Heptadecylcyclohexane Octadecylcyclohexane N onadecylcyclohexane... 

Likewise it is possible to differentiate between substituted and unsubstituted alicycles using inclusion formation with 47 and 48 only the unbranched hydrocarbons are accommodated into the crystal lattices of 47 and 48 (e.g. separation of cyclohexane from methylcyclohexane, or of cyclopentane from methylcyclopentane). This holds also for cycloalkenes (cf. cyclohexene/methylcyclohexene), but not for benzene and its derivatives. Yet, in the latter case no arbitrary number of substituents (methyl groups) and nor any position of the attached substituents at the aromatic nucleus is tolerated on inclusion formation with 46, 47, and 48, dependent on the host molecule (Tables 7 and 8). This opens interesting separation procedures for analytical purposes, for instance the distinction between benzene and toluene or in the field of the isomeric xylenes. 

Fig. 12.4. Vapor-to-water transfer data for saturated hydrocarbons as a function of accessible surface area, from [131]. Standard states are 1M ideal gas and solution phases. Linear alkanes (small dots) are labeled by the number of carbons. Cyclic compounds (large dots) are a = cyclooctane, b = cycloheptane, c = cyclopentane, d = cyclohexane, e = methylcyclopentane, f = methylcyclohexane, g = cA-l,2-dimethylcyclohexane. Branched compounds (circles) are h = isobutane, i = neopentane, j = isopentane, k = neohexane, 1 = isohexane, m = 3-methylpentane, n = 2,4-dimethylpentane, o = isooctane, p = 2,2,5-tri-metbylhexane. Adapted with permission from [74], Copyright 1994, American Chemical Society...

The second termination reaction is alkyl chain end transfer from the active species to aluminium [155]. This termination becomes major one at lower temperatures in the catalyst systems activated by MAO. XH and 13CNMR analysis of the polymer obtained by the cyclopolymerization of 1,5-hexadiene, catalyzed by Cp ZrCl2/MAO, afforded signals due to methylenecyclopentane, cyclopentane, and methylcyclopentane end groups upon acidic hydrolysis, indicating that chain transfer occurs both by /Miydrogen elimination and chain transfer to aluminium in the ratio of 2 8, and the latter process is predominant when the polymerization is carried out at — 25°C [156]. The values of rate constants for Cp2ZrCl2/MAO at 70°C are reported to be kp = 168-1670 (Ms) 1, kfr = 0.021 - 0.81 s 1, and kfr = 0.28 s-1 [155]. 

Methylcyclohexanol, see Methylcyclohexane Methylcyclopentane, see Benzene, Cyclohexane, Cyclopentane, Hexane Methyl diazene, see 1,1-Dimethylhydrazine Methyldibenzofuran, see Pyrene Methyl 5-(2,4-dichlorophenoxy)anthranilate, see Bifenox... 

Tantalum hydride(s) also catalyzes the hydrogenolysis of cyclic alkanes (substituted or not) but the reachvity order decreases with the cycle size as cycloheptane > methylcyclohexane > cyclohexane > methylcyclopentane > cyclopentane for the latter no reaction is actually observed (Figure 3.8). Activity decreases with hme and becomes low after 20 h. 

Figure 3.8 Conversion with time in the hydrogenolysis of cycloalkanes (19Torr, 14.5 equiv.) catalyzed by (=SiO)2TaH (3) at 160°C under hydrogen (470Torr) cycloheptane ( ), methylcyclohexane ( ), cyclohexane ( ), methylcyclopentane (A) and cyclopentane (x).

Figure 8 Connection between primary C-H and C-C bond ruptures during radiolysis and photolysis. Alkanes (1) propane, (2) w-butane, (3) -pentane, (4) -hexane, (5) w-heptane, (6) n-octane, (7) w-decane, (8) isobutane, (9) neopentane, (10) 3-methylpentane, (11) 2,2-dimethylbutane, (12) isooctane, (13) cyclopentane, (14) cyclohexane, (15) cycloheptane, (16) cyclooctane, (17) cyclodecane, (18) methylcyclopentane, (19) methylcyclohexane, (20) ethylcyclohexane, (21) 1,1-dimethylcyclohexane, (22) cis-l,2-dimethylcyclohexane, (23) fraw5-l,2-dimethylcyclohexane, (24) cis-1,3-dimethylcyclohexane, (25) trarw-l,3-dimethylcyclohexane, (26) cw-l,4-dimethylcyclohexane, (27) trawi-l,4-dimethylcyclohexane. (From Refs. 18, 29, 91, 92, 99, 100, 108, 110, 111, 113, 114, and 160.)...

Earlier work on the exchange of methylcyclopentane and methylcyclo-hexane over nickel catalysts at 150°-200° had not shown any discontinuities in the distribution pattern of the products (S9). There was a uniform rise up to a maximum for the fully deuterated species. This is not surprising, since similar behavior was noted with cyclopentane and cyclohexane under the same conditions. At these high temperatures the interchange reaction occurs sufficiently readily to mask any division of the hydrogen atoms into sets. 

A modification of this method utilizes the direct conversion of l,2-bis(trimethyl-siloxy)cyclobutene in one step to 2,2-disubstituted cyclopentane-1,3-diones. For example, 2-ethyl-2-methylcyclopentane-l,3-dione (3) was obtained in 91% yield from 1.2-bis(trimethyl-siloxy)cyclobutene and butan-2-one 2,2-dimethylpropane-l,3-diyl acetal.41 Further examples... 

The reaction of CH2 from CH2N2 photolysis with cyclopentane at — 75°C. and 15°C. in the liquid phase gave methylcyclopentane with less than 0.1% cyclohexane, showing that ring enlargement by insertion of CH2 into C—C bonds did not occur.24... 

Cyclohexane-methylcyclopentane isomerization21 can be depicted as in Scheme 4.2. The isomerization of substituted cyclopentanes and cyclohexanes to polymethylcyclohexanes similarly occurs by way of a series of consecutive steps... 

Table 4.6. Methyl Substituent Effects on 13C Chemical Shifts of Cyclopentane and Methylcyclopentane Resonances [210]...

Cyclopentane reagents used in synthesis are usually derived from cyclopentanone (R.A. Ellison, 1973). Classically they are made by base-catalyzed intramolecular aldol or ester condensations (see also p. 55). An important example is 2-methylcyclopentane-l,3-dione. It is synthesized by intramolecular acylation of diethyl propionylsuccinate dianion followed by saponification and decarboxylation. This cyclization only worked with potassium t-butoxide in boiling xylene (R. Bucourt, 1965). Faster routes to this diketone start with succinic add or its anhydride. A Friedel-Crafts acylation with 2-acetoxy-2-butene in nitrobenzene or with pro-pionyl chloride in nitromethane leads to acylated adducts, which are deacylated in aqueous acids (V.J. Grenda, 1967 L.E. Schick, 1969). A new promising route to substituted cyclopent-2-enones makes use of intermediate 5-nitro-l,3-diones (D. Seebach, 1977). 

Cracking and disproportionation in the reaction of hexane could be suppressed by the addition of cycloalkanes (cyclohexane, methylcyclopentane, cyclopentane).101 Furthermore, 3-methylpentane and methylcyclopentane also reduced the induction period. These data indicate that reactions are initiated by an oxidative formation of alkene intermediates. These maybe transformed into alkenyl cations, which undergo cracking and disproportionation. When there is intensive contact between the phases ensuring effective hydride transfer, protonated alkenes give isomerization products. 

Rates of the losses of methyl and methane from the molecular ion of methylcyclopentane have been determined over the time range 40 ps to microseconds [288]. The loss of ethylene from methylcyclopentane and decompositions of methylcyclohexane were also investigated. With support from I3C labelling, it was suggested that at times shorter than 1 ns, methyl was lost from the intact cyclopentane ion, but that at longer times ring opening preceded the decomposition. 

Fig. 3.5. Relationship between log (retention time) and boiling point for a range of hydrocarbons on squalane at 43°C. A, aliphatics (and benzene) B, alicyclics, 1-4 = C5-Cg n-alkanes 5 = 2-methyl-butane 6 = 2-methylpentane 7 = 2,3-dimethylbutane 8-12 = C4-C8 1-olefins 13,15,17 = trans-(but-2-ene, pent-2-ene and hept-2-ene) 14,16,18 = e/s-(but-2-ene, pent-2-ene and hept-2-ene) 19 = 2-methylbut-l-ene 20 = 2-methylpent-l-ene 21 = 4-methylpent-l-ene 22 = 2-methylbut-2-ene 23 = cyclopentane 24 = cyclohexane 25 = methylcyclopentane 26 = methylcyclohexane 27 = cyclo-pentene 28 = cyclohexene 29 = 4-methylcyclohexane 30 = 1,3-butadiene 31, 32 = trans- and cis-1,3-pentadiene 33 = diallyl 34, 35 = trans- and c s-2-methyl-l,3-pentadiene 36 = cyclopentadiene ...

A mixed reagent formed from Ge[CH(SiMc3)2]2 or Ge[N(SiMe3)2]2 and PhX (X = Cl, Br, I) was shown to reaction directly with alkanes (cyclohexane, cyclopentane, butane, methylcyclopentane), aromatics (toluene, ethyl... 

Figure 1. The content of a) C5 b) and c) C7 components in the naphthas as a function of the initial boiling point (IBP). CP=cyclopentane MCP=methylcyclopentane C7CP=dimethyl- and ethyl -cyclopentane CH=cyclohexane MCH=methylcyclohexane BEN=benzene TOL=toluene.

Hindin et al. (18) published data showing benzene formation to proceed readily from methylcyclopentane over mechanical mixtures of platinum bearing particles and silica-alumina, at atmospheric pressure and near 500°C. temperature. Under these conditions the equilibrium constant for conversion of a cyclopentane to a cyclopentene is of the order of unity. Consequently, the first step, if it is catalyzed by X, can itself proceed with... 

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