2-methyl butane density

Fig. 4. Retentkin diagrams for ( ) 2-methyl butane on low density prdyethylene and for (o) n-pentane on medium denrity polyefliylene...

It was found that if the content of the hydrocarbons extracted by supercritical 2-methyl-butane were analyzed, no hydrocarbons other than C12 alkene (two isomers) were detected. It is clear that C12 alkene, derived from oligomerization reactions, deposited onto catalytic sites and deactivated the catalyst. More specifically, high molecular weight alkenes such as C12, which have high electron density, might combine strongly with Lewis acid sites inside... 

Amyl alcohol (iso-amyl alcohol, 3-methylbutan-l-ol or 2-methyl-butan-4-ol). A colourless liquid with a characteristic odour. It has a density of 0.81 gcm . It should be kept in a metal box or cupboard. 

The EPR spectra of semidione radical anions can provide information on the spin density at the individual atoms. "The semidione derived from butane-2,3-dione, for example, has a spin density of 0.22 at each oxygen and 0.23 at each carbonyl carbon. The small amount of remaining spin density is associated with the methyl groups. This extensive delocalization is consistent with the resonance picture of the semidione radical anion. 

The data suggest that much of the unpaired electron density in the bicyclo[1.1.0] butane radical cation is associated with the two bridgehead carbon atoms, but that in the l,3-dimethylbicyclo[1.1.0]butane radical cation about 15% of the unpaired electron density is associated with the methyl substituents at these positions. 

The degree of crystallinity and spheralite density of PLA also increased with an increase in the number of branches. This view is not supported by other works in the field. The presence of short chain branches in polyethylene delayed the onset of nucleation and the growth of crystalline stractures. Star-chain branched PA-11 had low crystallization rate because star-branched core and its adjacent chains were unable to crystallize. Methyl groups may still be included in the PE orthorhombic crystal lattice, but with increased methyl group content, polymer gradually looses its ability to crystalUze when the methyl content reaches 20 wt%. If short-chain brarrches increase in size to 1-butane, 1-hexane, 1-octane, the crystallization is even more severely hampered. ... 

Figure 5 shows the calculated electron density distribution as a slice through the C-H-C linkage of the transition state. Clearly, the H atom has equal electron overlap between the C atom of the parent butane molecule and the C atom of the incoming methyl radical. As such, it can go downhill either way along the energy potential surface. This is an important feature, it keeps the radical alive and therefore makes the chain reaction propagate. 

Figure 5. Calculated electron density distribution of the butane + methyl transition state. The 2-D map is sliced through the key C-H-C hnkage.

According to the data presented, the value of the ionization potential (IP) for the transition states is correlated with the activation eneigy and increases as the number of alkyl substituents at the double bond grows. For ethylene of the transition state Ic the IP value amounts to 12.28 eV whereas this value of butane-2 is already 12.28 eV. The exception is the isobutylene the IP and A Gt 298 values of which are minimum in the considered alkene series. It is probably e qilained by F effect of two methyl substituents leading to a considerate distortion in electronic density of the double bond. 

Poly(4-methyl-2-pentyne) [PMP] is a glassy, disubstituted, purely hydrocarbon-based polyacetylene. PMP has a density of only 0.78 g/cm and a high fractional free volume of 0.28. The polymer has very high hydrocarbon permeabilities for example, the /i-butane permeability of PMP in a mixture of 2 mol% n-butane in methane is 7,500 X lO l cm3(STP) cm/cm2 s cmHg at 25 C. In contrast to conventional, low-free-volume glassy polymer membranes, PMP is significantly more permeable to n-butane than to methane in gas mixtures. In this paper, we present the gas permeation properties of PMP in mixtures of -butane with methane. The mixed-gas permeation and physical aging properties of PMP are compared to those of poly(l-trimethylsilyl-l-propyne), the most permeable polymer known. 

Figure 12 Contour maps of the electron density p(r) in a, of the kinetic energy density G(r) in b, and of the virial field V(r) in c for a methylene group adjacent to a methyl group in n-butane and w-pentane. The plane shown contains the carbon and hydrogen nuclei. The C-H bond cps and the associated bond paths and intersections of the interatomic surfaces are shown in a. The corresponding cps and virial paths are shown in c. This group and its properties are transferable between these two molecules to within the experimental accuracy of heats of formation. All three fields are locally proportional to the total energy density, G(r) and V(r) by theory, p(r) by observation...

So-called centre cracking produces a C4-C5 olefin fraction which rapidly isomerises to isobutene and isoamylene. These products were converted to methyl tertiary butyl ether (MTBE) and tertiary amyl methyl ether (TAME) by reaction with methanol to produce octane-enhancing additives for use in reformulated gasoline. Propane and n-butane are also produced. Fresh ZSM-5 also cracks paraffins imtil the acid site density decreases. Eventually, olefin cracking activity dechnes but isomerization activity is retained. Regular addition of fresh ZSM-5 is therefore required to maintain the shape-selective activity. 

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