Other Alkanes

The alkan olamines discussed here exhibit the chemical reactivity of both amines and alcohols, as is the case with other alkan olamines. Typically, they attack copper, brass, and aluminum, but not steel or iron. Alkan olamines are useful as amination agents however, the reactivity of both the amino and alcohol... 

This will generally be tr-ue as we proceed to look at other alkanes as the number of carbon atoms increases, so does the boiling point. All the alkanes with four car bons or less are gases at room temperature and atmospheric pressure. With the highest boiling point of the three, propane is the easiest one to liquefy. We are all faniliar- with propane tanks. These are steel containers in which a propane-rich mixture of hydrocar bons called liquefied petroleum gas (LEG) is maintained in a liquid state under high pressure as a convenient clean-burning fuel. 

Hydrogens on carbon next to aromatic rings also show distinctive absorptions in the NMR spectrum. Benzylic protons normally absorb downfield from other alkane protons in the region from 2.3 to 3.0 5. 

Nitration of alkanes can be carried out in the gas phase at 400°C or in the liquid phase. The reaction is not practical for the production of pure products for any alkane except methane. For other alkanes, not only does the reaction produce mixtures of the mono-, di-, and polynitrated alkanes at every combination of positions, but extensive chain cleavage occurs. A free-radical mechanism is involved. ... 

C09-0122. Cyclopropane, C3 Hg, which has three carbon atoms in a ring, is far more reactive than other alkanes. 

Note that the main difference between zirconium hydride and tantalum hydride is that tantalum hydride is formally a d 8-electron Ta complex. On the one hand, a direct oxidative addition of the carbon-carbon bond of ethane or other alkanes could explain the products such a type of elementary step is rare and is usually a high energy process. On the other hand, formation of tantalum alkyl intermediates via C - H bond activation, a process already ob-... 

The C-C and C-H BDEs for ethane are 377.0 and 423.0kJ/mol, respectively, and the H-0 BDE of hydroperoxyl (HO2 ) radical is only 207.5kJ/mol. The large reaction endothermicities for reactions 6.4 and 6.5 highlight the unlikeliness of their occurrence at lower temperatnres. In pyrolytic (heat, but no oxidant) or high fuel/oxidant ratio conditions, the endothermicities indicate that ethane and other alkanes will... 

Methane, ethane, and other alkanes react with fluorine, chlorine, and bromine. 

Unlike methane and the other alkanes, aromatic hydrocarbons have absorptions in the UV part of the spectrum, and thus may be detected through UV spectrometry using silica fibers. This scheme is useful for "aromatic" water pollutants such as toluenes and xylenes with their absorption bands between 250 and 300 nm. Similarly, nitrate anion can be monitored (albeit with low sensitivity) in water via its UV absorption at 250 nm. 

This test is used for both in vitro and in vivo determinations. It involves reacting thiobarbituric acid (TBA) with malondialdehyde (MDA), produced by lipid hydroperoxide decomposition, to form a red chromophore with peak absorbance at 532 nm (Fig. 10.1). The TBARS reaction is not specific. Many other substances, including other alkanals, proteins, sucrose, or urea, may react with TBA to form colored species that can interfere with this assay. 

When ethanol was substituted for propane, fewer moles of oxygen were required, but fewer moles of carbon dioxide and water were produced. The bond energies of the reactants decreased by (6486 kJ - 4726 kJ) = 1760 kJ, but the bond energies of the products decreased even more by (8498 kJ - 5974 kJ) = 2520 kJ. Therefore, we can deduce that the combustion of ethanol is less exothermic than that of propane and the other alkanes. 

Obtain samples of the following 11 organic liquids contained in individual small dropper bottles n-hexane (or other alkane), acetonitrile, methylene chloride, acetone, toluene, methanol, diethyl ether, ethyl acetate, ethylbenzene, ethanol, and chloroform. Then label each of the test tubes from step 1 with the names, or an abbreviation of the names, of these liquids. 

The problem of using any of the previous equations is that the solubility data of CO in hexane are scarce [318]. Oldani and Bor estimated values for the solubility factors of CO in hexane based on literature data for other alkanes, for example, s = 0.012 mol dm-3 bar-1 at 20 °C [319], Note that this value implies that [CO] in hexane is about 2 mol dm-3 under the experimental conditions (pco = 198 bar). 

In fluorosulfonic acid the anodic oxidation of cyclohexane in the presence of different acids (RCO2H) leads to a single product with a rearranged carbon skeleton, a 1-acyl-2-methyl-1-cyclopentene (1) in 50 to 60% yield (Eq. 2) [7, 8]. Also other alkanes have been converted at a smooth platinum anode into the corresponding a,-unsaturated ketones in 42 to 71% yield (Table 1) [8, 9]. Product formation is proposed to occur by oxidation of the hydrocarbon to a carbocation (Eq. 1 and Scheme 1) that rearranges and gets deprotonated to an alkene, which subsequently reacts with an acylium cation from the carboxylic acid to afford the a-unsaturated ketone (1) (Eq. 2) [8-10]. In the absence of acetic acid, for example, in fluorosulfonic acid/sodium... 

Theoretical and experimental studies revealed a common intermediate for the elimination of CHs" and CH4 from isobutane and other alkanes of similar size. The additional hydrogen needed may originate from either terminal position of the propyl moiety [77,78]... 

This reaction can also be planned between methane and any other alkane to form a hydrocarbon mixture and is a valorization of methane. It involves the breaking and the formation of a C-H and a C-C bond. 

Reduction with H2 in the presence of Fe, Ni, or Ru produces methane and other alkanes along with oxygenates. 

The yield determined in a certain type of experiment usually strongly depends on the assumptions made about the formation mechanism. In the older literature, the excited molecules were often assumed to be produced solely in neutral excitations [127,139-143] and energy-transfer experiments with Stern-Volmer-type extrapolation (linear concentration dependence) were used to derive G(5 i). For instance, by sensitization of benzene fiuorescence, Baxendale and Mayer established G(5 i) = 0.3 for cyclohexane [141]. Later Busi [140] corrected this value to G(5 i) = 0.51 on the basis that in the transfer, in addition to the fiuorescing benzene state S, the S2 and S3 states also form and the 82- 81 and 83 81 conversion efficiencies are smaller than 1. Johnson and Lipsky [144] reported an efficiency factor of 0.26 0.02 per encounter for sensitization of benzene fluorescence via energy transfer from cyclohexane. Using this efficiency factor the corrected yield is G(5 i) = 1.15. Based on energy-transfer measurements Beck and Thomas estimated G(5 i) = 1 for cyclohexane [145]. Relatively small G(5 i) values were determined in energy-transfer experiments for some other alkanes as well -hexane 1.4, -heptane 1.1 [140], cyclopentane 0.07 [142] and 0.12 [140], cyclooctane 0.07 [142] and 1.46 [140], methylcyclohexane 0.95, cifi-decalin 0.26 [140], and cis/trans-decalin mixture 0.15 [142]. 

The data in Figs. 3 and 4 show that the ease of removal of a lattice oxygen, which can also be expressed in terms of the reducibility of the neighboring cations, has a strong effect on the selectivity for oxidative dehydrogenation of butane. If this is the only factor that determines selectivity, then a catalyst that is selective for dehydrogenation of butane, such as Mg3(V04)2, will be selective for other alkanes as well. Likewise, any catalyst that contains bonds will not be... 

The behavior of ethane is different from the other alkanes. It is the only alkane that undergoes significant dehydrogenation on the VPO catalyst, as well as the only one for which combustion is the predominant reaction on VMgO. However, an ethyl species is too small to interact with two V ions simultaneously on any of the three catalysts. A phenomenological explanation of this behavior of ethane has been suggested [10]. In this explanation, the possible reactions of ethyl, propyl, and 2-methylpropyl species were compared by statistically counting the number of various types of bonds in each species ... 

In these species, a reaction in which a C -H bond is broken would lead to dehydrogenation. However, breaking a C"-H bond or cleaving a C"-C bond would lead to degradation products. The statistical probabilities of these three processes are proportional to the number of these bonds in the species, which are shown in Table III. They show that these species only differ in the relative number of C -H bonds. If the C"-H and the C-C bond react with equal probability, whereas the C -H bond reacts somewhat faster, combustion would be more likely for ethane than for the other alkanes. Since the reaction conditions, especially temperatures, for the data on Mg2V207 and Mg3(V04)2 were similar, this argument would account for the low dehydrogenation selectivity observed on these two oxides. 

Table 6.2 summarizes rate constants for some OH-al-kane reactions for recent recommendations for other alkanes, see Atkinson (1994, 1997a) and Atkinson et al. (1997a). 

Bunce, N. J., K. U. Ingold, J. P. Landers, J. Lusztyk, and J. C. Scaiano, Kinetic Study of the Photochlorination of 2,3-Dimethyl-butane and Other Alkanes in Solution in the Presence of Benzene. First Measurements of the Absolute Rate Constants for Hydrogen Abstraction by the Free Chlorine Atom and the Chlorine Atom-Benzene tr -Complex. Identification of These Two Species as the Only Hydrogen Abstractors in These Systems, . /. Am. Chem. Soc., 107, 5464-5472 (1985). 

Halogenation of alkanes had long been known, and in 1930 the kinetics of the chlorination of chloroform to carbon tetrachloride were reported by Schwab and Heyde (equation 40), while the kinetics of the chlorination of methane were described by Pease and Walz in 1931. Both of these studies showed the currently accepted mechanism, which was extended to reactions in solution by Hass et al. in 1936. The free radical halogenation mechanism of other alkanes was described by Kharasch and co-workers, ° including side chain halogenation of toluene. 

Excited-state Mg atoms react with methane and other alkanes via H atom abstraction in the gas phase (equation 1). By studying the vibrational states of the MgH product, information on the mechanism has been inferred. It has been found that regardless of the alkane, RH (and thus the C—H bond strength), the vibrational state distributions are essentially identical. This suggests that long-lived vibrationaUy excited [RMgH] complexes are not intermediates for equation 1 in the gas phase. The situation is quite different for excited-state Mg atoms reacting with methane under matrix conditions, where the insertion product (equation 2) is sufficiently stable for analysis via infrared spectroscopy ". Calcium atoms have been shown to insert into the C—H bonds of cycloalkanes. ... 

The principal polyolefins are low-density polyethylene (ldpe), high-density polyethylene (hope), linear low-density polyethylene (lldpe), polypropylene (PP), polyisobutylene (PIB), poly-1-butene (PB), copolymers of ethylene and propylene (EP), and proprietary copolymers of ethylene and alpha olefins. Since all these polymers are aliphatic hydrocarbons, the amorphous polymers are soluble in aliphatic hydrocarbon solvents with similar solubility parameters. Like other alkanes, they are resistant to attack by most ionic and most polar chemicals their usual reactions are limited to combustion, chemical oxidation, chlorination, nitration, and free-radical reactions. 

---