Propane Propene

Two GC columns Porapak Q (for C02 and water analyses) and Molecular sieve 5A (hydrogen, oxygen, and CO) were used with two thermal conductivity detectors and another GC column with modified y-Al203 (methane, ethane, ethene, propane, propene, and C4 hydrocarbons) was used with a flame ionisation detector. Carbon and oxygen balances were within 100+5%. 

Fig. 15.11 (a),(b) Fraction of CNT catalysts combusted after 24 h time on stream in a 02/He gas mixture (a) CNTs, (b) 5 wt% P205/CNTs. (a),(b) Reprinted with permission from [25]. Copyright (2011) American Chemical Society, (c) Catalytic performance of B203-modified CNT catalysts in the ODH of propane. Propene selectivity at 5 % propane conversion ( ) and reaction rate (o) as a function of B203 loading, (d) Reaction scheme of CNT-cataiyzed ODH. (c),(d) Reprinted with permission from [61]. Copyright (2009) Wiley VCH. 

In a similar study, Zhang and Wang (1997) studied the reaction of zero-valent iron powder and palladium-coated iron particles with trichloroethylene and PCBs. In the batch scale experiments, 50 mL of 20 mg/L trichloroethylene solution and 1.0 g of iron or palladium-coated iron were placed into a 50 mL vial. The vial was placed on a rotary shaker (30 rpm) at room temperature. Trichloroethylene was completely degraded by palladium/commercial iron powders (<2 h), by nanoscale iron powder (<1.7 h), and nanoscale palladium/iron bimetallic powders (<30 min). Degradation products included ethane, ethylene, propane, propene, butane, butene, and pentane. The investigators concluded that nanoscale iron powder was more reactive than commercial iron powders due to the high specific surface area and less surface area of the iron oxide layer. In addition, air-dried nanoscale iron powder was not effective in the dechlorination process because of the formation of iron oxide. 

With A in kcal/mol, a few examples are (experimental values are given in parentheses) propane/propene, 860.1 (858.56) butane/butene, 1154.2 (1154.5) pentane/pentene, 1448.2 (1447.6) cyclohexane/cyclohexene, 1616.8 (1616.1) methylcyclohexane/l-methylcyclohexene, 1913.1 (1913.2) cyclohexane/1,4-cyclo-hexadiene, 1472.8 (1472.8), and butane/butadiene, 1010.2 (1010.1). (Where appropriate, the averages of the various alkene isomers were used.)... 

Since it is now well accepted that the role of the additive in the H-ZSM-5 based catalysts is to Increase the rate of propane dehydrogenation it is clear that the additive should be sufficiently active to establish rapidly the thermodyneunic equilibrium propane-propene. Ga203 or ZnO exhibits with respect to Pt catalysts lower dehydrogenating properties. Nevertheless, when supported on H-ZSM-5, they were found to promote more efficiently the aromatization of propane, and also the... 

The initial molar propane/propene-ratio (at 10 % of catalyst life time) is a measure of catalyst activity. It grossly correlates with the catalyst Si/Al-ratio. Fig. 7 concerns further proofs of catalyst life time. No correlation is observed between the amount of coke deposited and the total amount of methanol which is converted during the catalyst life time. However, a correlation appears to exist between (1) coke selectivity and catalyst life time and (2) methane selectivity and coke selectivity. 

In this system the concentrations of propane, propene, and formaldehyde were kept sufficiently small that the predominant reactions were those of the NO. species. By keeping the NO concentrations high, 03 concentrations could be kept low because reaction (8)... 

Sproviero and Burton367 have studied the contribution of stereoelectronic interactions to 3J(F1,F[) and 4J(F1,F[) couplings using RPA calculations and NBO analyses. As model compounds they chose ethane, propane, propene and methylcyclopropane. 

No isolable organometallic products with Al vapor from propane, propene, 1- or 2-butenes, 1,3-C4H6, or propyne (104, 110, 116). 

Hydrocarbons, general Methane Propane Propene Butane Isobutane Pentane Isopentane Pentene Hexane Hexene Benzene Heptane Heptene Octane Octene Nonane Nonene Decane Decene... 

In general, a C3 stream is obtained that contains propane, propylene, pro-padiene, and propyne, and these are separated in a C3 distillation column, also referred to as the C3 splitter. Propane-propylene separation and, as a rule, olefin-paraffin separation, are energy-intensive, and some estimates are that 1.27 x 1017 J are used for olefin-paraffin separation on an annual basis [4] while roughly 3% is used by paraffin-olefin distillation columns [5]. This provides an incentive to examine the propane-propene separation, which is an example of paraffin-olefin separation. 

The analysis presented in this chapter is an example of how the principles of thermodynamics can be applied to establish efficiencies in separation units. We have shown how exergy analysis or, equivalently, lost work or availability analysis can be used to pinpoint inefficiencies in a distillation column, which in this case were the temperature-driving forces in the condenser and the reboiler. The data necessary for this analysis can easily be obtained from commonly used flow sheeters, and minimal extra effort is required to compute thermodynamic (exergetic) efficiencies of various process steps. The use of hybrid distillation has the potential to reduce column inefficiencies and reduce the number of trays. We note that for smaller propane-propene separation facilities (less than 5000bbl/day [10]), novel technologies such as adsorption and reactive distillation can be used. 

Gokhale, V. Hurowitz, S. Riggs, J.B. A comparison of advanced distillation control techniques for a propane/propene splitter. Ind. Eng. Chem. Res. 1995, 34, 4413-4419. 

Thus methane is released from the fines mainly as CD4 and CH4 in ratios (CD4 CH4) varying from 2.2 to 12.7 the most common ratio being in the range 3 1 to 5 1. Some is also released as CD3H but is considered to be an acid hydrolysis product and is included with CD4 for quantitative measurement. Other partly deuterated species (CH2D2,CH3D) are released in only trace concentrations. Similarly, ethane is released as both undeuterated and deuterated (and almost fully deuterated) species. Other species (ethylene, acetylene, propane, propene, butane and butene) appear to be mainly deuterocarbons. The Cj to C4 deuterocarbons are thought to arise from acid hydrolysis of carbides in the samples (Table 2). 

In zeolites, this barrier is even higher. As discussed in Section II.B, the lower acid strength and the interaction between the zeolitic oxygen atoms and the hydrocarbon fragments lead to the formation of alkoxides rather than carbenium ions. Thus, extra energy is needed to transform these esters into carbonium ionlike transition states. Quantum-chemical calculations of hydride transfer between C2-C4 adsorbed alkenes and free alkanes on clusters representing zeolitic acid sites led to activation energies of approximately 200 kJ/mol for isobutane/tert-butoxide (29), 230-305 kJ/mol for propane/sec-propoxide, and 240 kJ/mol for isobutane/tert-butoxide (32), 130-150 kJ/mol for ethane/ethene (63), 95-105 kJ/mol for propane/propene, 88-109 kJ/mol for isobutane/isobutylene, and... 

At lower temperature, Williams [8] finds mainly ethylene, propane, propene and butene as major components. Kaminsky [11], at higher temperature, finds mainly methane and ethylene. 

At higher temperature (700°C), in slow pyrolysis, the gas phase contains less methane and more propane, propene and butene than by flash pyrolysis (see Tables 10.9 and 10.12). 

Non-methane hydrocarbons (NMHCs such as ethane, ethene, propane, propene, and isoprene) are trace atmospheric constituents that play an important role in both providing a sink for hydroxyl radicals and in controlling ozone concentrations (Donahue and Prinn, 1990). The oceans are known to be a source of NMHCs to the atmosphere, although globally they are significantly smaller than terrestrial sources. However, the main marine-produced NMHCs, ethane and propene, may have an important local impact on atmospheric photochemistry (Plass-Dulmer et al., 1995), particularly in... 

Similar observations have been made with isopropyl iodide for which the main hydrocarbon photolysis products are propane, propene and 2,3-dimethyl-butane. 

Gant and Yang studied the decay of gaseous T2 in cyclopropane (cyclopropane pressure more than 100 times that of T2). The main products are tritiated cyclopropane, propane, propene, ethylene, ethane and acetylene. Table 7 gives the yields of the main products as fractions from the number of tritium atoms, incorporated into these compounds. 

The transformation of n-butane over H-ZSM-5 resulted in the formation of aromatic hydrocarbons benzene, toluene and isomers of xylenes. The gaseous products obtained were methane, ethane, ethene, propane, propene, butenes (cis-, trans- and iso- butenes) and hydrogen. The n-butane conversion and selectivity to aromatics increased with increasing temperature. More cracking products than aromatics were formed over this catalyst. 

Reactions of n-hexane (nH) were studied in a closed loop glass circulation reactor [5, 8]. The catalyst (50 mg) was heated in air at 773 K and reduced in situ at 723 K with 500 Torr H2 for 3 h (with a liquid nitrogen trap). After evacuation, reaction mixtures consisting of 10 or 40 Torr n-hexane and 120 Torr hydrogen were introduced and runs between 5 and 50 (in some cases 0.5 and 135) min were carried out between 603 and 693 K. The products were analyzed by a capillary GLC column (50 m by 0.32 mm fused silica, CP Sil 5 coating) on a Packard Twe 437 GC. The range of analysis embraced Cj-Cg hydrocarbons including Cg aromatics. The pairs ethane-ethene and propane-propene could not be separated properly. Selectivities were calculated on the basis of effluent composition. 

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