Thermal Decomposition Mechanism for Ethanethiol

Abstract

The thermal decomposition of ethanethiol was studied using a 1 mm × 2 cm pulsed silicon carbide microtubular reactor, CH3CH2 SH+Δ →Products. Unlike previous studies these experiments were able to identify the initial ethanethiol decomposition products. Ethanethiol was entrained in either an Ar or a He carrier gas, passed through a heated (300−1700 K) SiC microtubular reactor (roughly ≤100 μs residence time) and exited into a vacuum chamber. Within one reactor diameter the gas cools to less than 50 K rotationally, and all reactions cease. The resultant molecular beam was probed by photoionization mass spectroscopy and IR spectroscopy. Ethanethiol was found to undergo unimolecular decomposition by three pathways: CH3CH2SH→(1) CH3CH2+SH, (2) CH3+H2C=S, and (3) H2C=CH2+H2S. The experimental findings are in good agreement with electronic structure calculations.

Study of Thermal Aging of Model Compounds Present in Asphalt Cement by GC/MS, ESI-MS, NMR, and FTIR

“…The chemical reactions occur by the formation of sulfanyl, SH (radical initialization), and hydrosulfide radicals, SH 2 (Figure 7b,c). 48,49 From the hydrosulfide radical formation (Figure 7b), the sulfur from another 2-naphthalenethiol molecule attacks the triple bond of the ring, while the carbon from the triple bond abstracts the hydrogen from the 2-naphthalenethiol molecule, forming the di(naphtalen-2-yl)sulfane (m/z 286). 49 From the sulfanyl radical formation (Figure 7c), a 2naphthalenethiol is deprotonated (propagation I and II), generating the dibenzothiol radical, which is linked with another dibenzothiol molecule, producing the 1,2-di-(naphthalen-2-yl)disulfane (m/z 318) (termination I).…”

“…According to the NIST library and the EI mass spectrum, the formation of two molecules that indicate a tendency for polymerization reactions was detected (Figure S15a,b). The chemical reactions occur by the formation of sulfanyl, SH (radical initialization), and hydrosulfide radicals, SH 2 (Figure b,c). , …”

Modeling Oil Shale Pyrolysis: High-Temperature Unimolecular Decomposition Pathways for Thiophene

“…A high-temperature pulsed microtubular reactor (or hyperthermal nozzle) was used to decompose thiophene. The microtubular reactor is a version of the Chen-Ellison reactor that has been used for several years to produce reactive intermediates. − The hyperthermal nozzle features a (1 mm ID × 3 cm long) SiC tube that can be heated up to 1700 K, with the temperature monitored by a type C thermocouple mounted to the outer wall of the SiC tube. A benefit of the microtubular reactor is the short residence time (50–100 μs) .…”

Enhanced Bimolecular Reaction in a Two-Component Fluid under Pyrolytic Conditions: In Situ Probing of the Pyrolysis of Jet Fuel Surrogates Using a Supersonic Expansion Molecular Beam Mass Spectrometer

“…It is the controlled pyrolysis of fuels that will enable an endothermic-capable fuel system, i.e., a fuel or fuel system selective for endotherm-producing reactions and selective against the formation and deposition of coke. There is a tremendous amount of data in the literature for the pyrolysis of various fuel-related compounds, with many gas-phase, − shock tube, − and reactor-based − studies reported. Models describing the chemical pathways and reaction kinetics are available for many systems, − yet it is currently not possible to design an endothermic-capable fuel or fuel system based on these data alone; experience has shown that significant trial-and-error testing is generally necessary to obtain acceptable performance results.…”