Butane definition

Allinger NL, Fermann JT, Allen WD, Shaefer III HF (1997) The torsional conformations of butane definitive energetics from ab initio methods. J Chem Phys 106 5143-5250... 

Definition (in vol %) Mainly butanes/butenes < 19% propane/propylene 90% approx, propane/propylene 10% ethane/ethylene/butanes/butenes Mainly propane, butanes and propylene/butenes/pentanes/pentenes... 

The advantage of this definition is that it does not depend on measuting the tangent of the response curve, although the variation ia the value of the blending octane number is greater. Typically, BONs are measured at an 80/20 mixture. This technique is also usehil when trying to measure the octane of a compound such as butane or methanol that is difficult or impossible to measure ia its pure state. 

The catalysts that allow the production of maleic anhydride from n-butane with high selectivity, like (V0)2P207, are characterized by a strong acidity, that, like a strong basicity, favors the decomposition of alkoxides to give the olefin and the diene. The catalysts that allow the production of maleic anhydride, either from n-butane or from butenes and butadiene, necessarily have particular sites that allow the insertion of oxygen atoms in the 1,4-position of butadiene. These sites are definitely absent on combustion catalysts. 

As expected from Table 5.7, this environmental quotient for conventional oxo processes (basis Co catalysts) and for the manufacture of the bulk chemical -butanal is actually about 0.6-0.9, depending on the definition of the term "target" product. The range 0.6-0.9... 

This conjugated enone/diene difference is more definitively seen in the 184 kJ mol-1 decrease in enthalpy of formation on going from 1-pentene to butanal, in contrast to the 177 kJ mol-1 going from (E)-l,3-pentadiene to irans -crotonaldehyde. For further discussion, see J. F. Liebman and R. M. Pollack, in The Chemistry ofEnones (Eds. S. Patai and Z. Rappoport), Wiley, Chichester,... 

If the blackness of the particulate matter collected on a filter is due to the graphitic carbon content of the sample, then the Km unit should convert to ambient elemental carbon concentrations. The form of that translation is apparent from the definition of the Km unit. Elemental carbon concentration measurements made by laboratory reflactometers calibrated against heated butane soot standards show that elemental carbon concentrations are linearly related to the log of the reflectance ratio R /R. Aerosol loadings stated in Km units should be directly proportional to elemental carbon concentrations sampled. 

High isobutane recycle purity is not required on HF alkylation units as is required on many H2SO4 units because relatively high normal butane concentrations in the reaction zone do not appreciably affect the quality of the alkylate. Isobutane purities below 60% are usually avoided, however, since this purity definitely gives lower-quality alkylate and the cost of recycling the normal butane is considerable in heat requirements as well as fractionation equipment requirements. 

Fig. (a) Butane (C4H]0) (b) 2-methlypropane (C4H10). Configurational Isomers — Alkenes and Cycloalkanes Definition... 

This is the common definition of conformers. The IUPAC definition also requires that a conformer correspond to a distinct potential energy minimum, such as the anti and gauche conformations of butane. 

The aim of such conditioning procedure is to reduce V(V) orthophosphate impurity phases in the presence of n-butane, crystallize (V0)2P207in the VPO catalysts and increase their surface area [10]. Several alternative definitions of the equilibrated state of VPO catalysts and models of an active and selective phase and surface sites have been advanced [4,10-13]. Some of the reasons for the reported differences in the catalytic performance of VPO catalysts may be attributed to ... 

The question now arises, how may we determine which one of the various formulas, in the case of the five hexanes for instance, is to be assigned to each individual compound of definite physical properties To which one of the butanes, pentanes and hexanes do we assign the straight chain formula or the name normal In the case of the butanes the answer and the reason for it are found in a new synthesis of one of the butanes. We have given one synthesis of the two butanes, viz., from propyl iodide and methyl iodide. As one propyl iodide yields one butane and the other yields the isomeric butane, we know that one of the two isomeric butanes must have the straight chain or normal formula. But we do not know whether the propyl iodide from which the butane boiling at + i is prepared, is really the one possessing the normal or the iso formula. Therefore, it will be seen that the relationship between the isomeric propyl iodides and the isomeric bu-... 

---