6998-50-1

Upstream product

• 157563-12-7 -1,2-dibromo-1-methylcyclohexane 
• 25909-68-6 [¹³C]-potassium cyanide 
• 110-56-5 1,4-dichlorobutane 
• 67-56-1 methanol 
• 1641-69-6 [13C]Carbon monoxide 
• 29809-11-8 <1-13C>phenol 

Relevant academic research and scientific papers

Bifunctional Catalysts for One-Step Conversion of Syngas into Aromatics with Excellent Selectivity and Stability

Syngas (CO/H2) is a key platform for chemical utilization of non-petroleum carbon resources. Among syngas transformation routes, the direct synthesis of aromatics, which are among the most important bulk chemicals, is less successful because of the limited selectivity and poor catalyst stability. We report a successful design of bifunctional catalysts composed of Zn-doped ZrO2 nanoparticles dispersed on zeolite H-ZSM-5 for one-step conversion of syngas to aromatics with high selectivity and stability. Aromatics with 80% selectivity at CO conversion of 20% were achieved, and there was no catalyst deactivation in 1,000 hr. Methanol and dimethyl ether were formed as major intermediates on Zn-doped ZrO2, which were subsequently converted into aromatics on H-ZSM-5 via olefins. We discovered a self-promotion mechanism of CO in the selective formation of aromatics. As well as being a reactant, CO facilitates the removal of hydrogen species formed on H-ZSM-5 in the dehydrogenative aromatization of olefins.

Conversion of methoxy and hydroxyl functionalities of phenolic monomers over zeolites

This study investigates the mechanisms of gas phase anisole and phenol conversion over zeolite catalyst. These monomers contain methoxy and hydroxyl groups, the predominant functionalities of the phenolic products of lignin pyrolysis. The proposed reaction mechanisms for anisole and phenol are distinct, with significant differences in product distributions. The anisole mechanism involves methenium ions in the conversion of phenol and alkylating aromatics inside zeolite pores. Phenol converts primarily to benzene and naphthalene via a ring opening reaction promoted by hydroxyl radicals. The phenol mechanism sheds insights on how reactive bi-radicals generated from fragmented phenol aromatic rings (identified as dominant coke precursors) cyclize rapidly to produce polyaromatic hydrocarbons (PAHs). Resulting coke yields were significantly higher for phenol than anisole (56.4% vs. 36.4%) while carbon yields of aromatic hydrocarbons were lower (29.0% vs. 58.4%). Water enhances formation of hydrogen and hydroxyl radicals, thus promoting phenol conversion and product hydrogenation. From this finding we propose phenol-water-zeolite combination to be a high temperature hydrolysis system that can be used to generate both hydrogen and hydroxyl radicals useful for other kinds of reactions.

Thermal rearrangement, XXV: The automerization of benzene as a radical-initiated reaction

The thermal isomerization of [1,4-D2]-(3a) and [1,2-13C2]benzene (1a) has been studied in excess hydrogen at 750-850°C with contact time less than 1.2 s and very low partial pressure in a quartz flow system. In both cases, the main isomerization products are the corresponding meta isomers. The data suggest a radical intramolecular interchange of the benzene carbon atoms by 1,2-C shifts. The multistep reaction cascade is initiated by H addition to the benzene ring followed by transannular homoallyl rearrangements involving the intermediate formation of bicyclo[3.1.0]hexenyl and cyclopentadienylmethyl radicals. This pathway constitutes a side reaction competing with the direct stabilization of the cyclohexadienyl radicals formed preferentially at high temperature. VCH Verlagsgesellschaft mbH, 1996.

The Thermal Aromatization of Methyl-1,3-cyclohexadienes - An Important Argument against Commonly Accepted Sigmatropic 1,7-H-Shift Reactions

It has been demonstrated that the methyl and ring C-atoms of methyl-1,3-cyclohexadienes interchange their positions intramolecularly during the thermal conversion to toluene at temperatures above 600 deg C in a quartz flow system.Gas phase pyrolysis of double 13C-labeled methyl-1,3-cyclohexadienes with 13C-labels for the primary and the tertiary C-atom gave definite 13C-distribution patterns in the aromatic ring systems of the formed toluene as well as benzene with far-reaching similarities.The NMR data of the toluene isotopomers definitely rule out that the observed integration of the methyl C-atom into the ring system proceeds via the hitherto well-established sequence: electrocyclic ring opening of the 5-methyl-1,3-cyclohexadiene to 1,3,5-heptatriene, its sigmatropic 1,7-H shift and ensuing recyclization of the 1,3,5-heptatriene to methyl-1,3-cyclohexadienes.