Oxidative Pyrolyses of Selected Hydrocarbons Using the Wall-less Reactor

Taylor, Jay E.; Kulich, Donald M.

doi:10.1021/bk-1976-0032.ch005

Cited by 6 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, a likely explanation for the activity of the quartz chips is that they effectively initiate radicals starting at 570 °C, which then undergo propagation and termination reactions in the gas-phase. These results appear to be consistent with the earlier work of Burch and Crabb. , Using nondilute gas mixtures of alkanes and air, the authors observed evidence for the onset of noncatalytic ODH pathways beginning at 575 and 550 °C for ethane and propane, respectively. , Initiation of these homogeneous reactions is suspected to occur via homolysis of the C–C bonds in either ethane or propane, yielding ethyl (CH 3 CH 2 ·), n-propyl (CH 3 CH 2 CH 2 ·), and isopropyl (CH 3 ·CHCH 3 ) radicals. − Then, the radicals can react with oxygen, with ethyl radicals yielding ethylene, n-propyl radicals yielding both ethylene and propylene, and isopropyl radicals yielding only propylene.…”

Section: Results and Discussionsupporting

confidence: 90%

Boron-Containing Catalysts for the Oxidative Dehydrogenation of Ethane/Propane Mixtures

Loiland

Zhao

Patel

et al. 2019

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

Oxidative dehydrogenation (ODH) of ethane and propane feeds has been examined under a variety of temperatures, flow rates, and gas compositions in a fixed bed reactor using boron nitride-based catalysts either promoted with various metal oxides or supported on silica. Tests performed at low conversion in the presence of a large amount of N 2 diluent indicated that addition of MgO to boron nitride (BN) led to a ∼10-fold increase in alkane conversion, with a drop in the C 2 −C 3 olefin selectivity from 90% to 79%. Testing using concentrated feeds with small amounts of diluent (3%) indicated that metal-oxide promoted BN catalysts could maintain C 2 −C 3 olefin selectivities as high as 65% at high alkane conversion (∼60%). Catalyst productivity values under these conditions approached 16 kg olefins kg cat −1 h −1 . Under nondilute conditions, the catalysts appear to act as initiators of radical reactions at the surface, after which the radicals desorb into the gas phase and undergo propagation steps.

show abstract

Section: Results and Discussionsupporting

confidence: 90%

Boron-Containing Catalysts for the Oxidative Dehydrogenation of Ethane/Propane Mixtures

Loiland

Zhao

Patel

et al. 2019

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

show abstract

“…The olefins (propylene and ethylene) and water also increased with increase in initial oxygen concentration as indicated in Figure 5 and 6, respectively. These observations are in agreement with the works of Niclause (1965), Blakemore (1973), and Taylor (1976.…”

Section: (12)supporting

confidence: 93%

“…There is also the clear indication that: (a) when olefins are the desired products of pyrolysis (in the absence of catalysts of course), traces of oxygen lead to their (olefins) formation in larger quantity; (b) the agreement between this work conducted at high temperatures (700 "C) and those of Niclause (1965), Blakemore (1973, and Taylor (1976) which were conducted at the lower temperatures (500-600 "C) suggests that the same mechanism that operates for oxidative pyrolysis at 500 OC, also applies a t temperatures employed in commercial pyrolysis. Binary gaseous diffusion coefficients in a nuclear graphite (H-451) along with the pore volume distribution were measured.…”

Section: (12)supporting

confidence: 55%

“…and Kulich (1976) which states that the oxygen-propane reaction does not take place a t a lower temperature than the oxygen-free pyrolysis of propane such that while the initiation steps can be represented by the following equations…”

Section: Mechanism and Modelmentioning

confidence: 99%

“…C3H7 ---* CZH, + CHB (8) Reactions 4 and 5 would then constitute the period of decreased rate while reactions 6 and 7 constitute the period of increased rate (Niclause, 1965;Taylor et al, 1976). According to Taylor and Kulich (19761, reaction 4 may be a reaction "type" represented by the following steps…”

Section: Mechanism and Modelmentioning

confidence: 99%

See 2 more Smart Citations

Oxidative Pyrolysis of Propane

Layokun¹

1979

Ind. Eng. Chem. Proc. Des. Dev.

View full text Add to dashboard Cite

Literature on the oxidative pyrolysis of propane is very sparse for temperatures above 600 OC. Hence the present work was carried out between 600 and 700 OC at 1 atm total pressure using a plug flow quartz reactor and the MS10-C2 mass spectrometer as the analytical tool. Small amounts of oxygen were added into the propane stream such that the oxygen can only participate in the early stages of reaction, thus throwing some light on the nature of the initiation reactions in pyrolysis and oxidation systems. Results were compared with computer predictions. The following observations were made: (1) a faster rate of decomposition of propane in the presence of oxygen than in its absence; (2) a product distribution (at the initial stages) in order of magnitude C3H8, C2H4, CH,, H, , and C2Hs as compared to the order CH, , C2H4, C3H6, H, , and C2H6 in the absence of oxygen; (3) the mechanism reported in the literature for temperatures between 500 and 600 "C is also operative at higher temperatures; (4) a 28 reaction step model fits the experimental data. The role of H 0 2 in relation to the observed product spectrum is also fully discussed

show abstract

Gas‐phase pyrolysis of 2,2,3,3‐tetramethylbutane using a wall‐less reactor

Taylor

Milazzo

1978

Int J of Chemical Kinetics

Self Cite

View full text Add to dashboard Cite

The pyrolysis of 2,2,3,3-tetramethylbutane (TMB) has been studied using the wall-less reactor. Under homogeneous conditions up to 670°C, the activation energy is 43.2 kcal/mol and log A is 10.70. The products are 2-methylpropene, hydrogen, propene, 2-methyl-2-butene, ethane, ethene, methane, neopentane, and 2,3-dimethyl-Z-butene in order of abundance. Addition of toluene, cyclopentadiene, o r nitrous oxide to the system increases both the activation energy and the A factor; whereas oxygen decreases both the activation energy and the A lactor. Incorporation of stainless-steel rods to provide surface has only a modest effect upon the rate. In view of this evidence, it appears that the homogeneous pyrolysis of TMB a t higher pressures i s a chain reaction under the described conditions.

show abstract

Oxidative Pyrolyses of Selected Hydrocarbons Using the Wall-less Reactor

Cited by 6 publications

References 0 publications

Boron-Containing Catalysts for the Oxidative Dehydrogenation of Ethane/Propane Mixtures

Boron-Containing Catalysts for the Oxidative Dehydrogenation of Ethane/Propane Mixtures

Oxidative Pyrolysis of Propane

Gas‐phase pyrolysis of 2,2,3,3‐tetramethylbutane using a wall‐less reactor

Contact Info

Product

Resources

About