Thermolysis of Phenethyl Phenyl Ether: A Model for Ether Linkages in Lignin and Low Rank Coal

Lignin pyrolysis reactions

“…1 Thermogravimetric analysis of milled wood lignin isolated from Japanese cedar (Cryptmeria japonica) [9] understanding the pyrolytic reactions of lignins. Hence, various model dimers including β-ether [20,27,28,34,[40][41][42][43][44][45][46][47][48][49][50][51][52][53], α-ether [20,30,34,45,47,49,51,54], β-aryl [20,31,32,47,54], β-β [33], and biphenyl [20,47,54] types, trimers [34,49,51] and oligomers/polymers such as dehydrogenative polymerization products of cinnamyl alcohols [35] and β-ether type polymers [55][56][57] have been used in pyrolysis studies. Phenolic (Ph) and non-phenolic (Non-Ph) model compounds are commonly used to represent the ends and repeating units of lignin macromolecules, respectively.…”

“…The Brit and Beste research group have extensively studied hydrogen abstraction reactions from the C α − H bond and subsequent cleavage of the β-ether bond using phenethyl phenyl ether and its derivatives [43,44,46].…”

Computational Study of Bond Dissociation Enthalpies for Substituted β‐O‐4 Lignin Model Compounds

“…[5,6] On the other hand, research is conducted to understand the thermal decomposition of this biopolymer to extract methanol, phenols, and substituted phenolic compounds. [3,4,[7][8][9][10][11][12][13][14][15][16][17][18][19][20] Lignin also shows promise as an alternative in the manufacture of carbon fibers. [21,22] Lignin pyrolysis comprises a profusion of varied processes that are difficult to probe in the laboratory and is often studied through model compounds.…”

“…Phenethyl phenyl ether (PPE) is the simplest model of the common b-O-4 linkage found in lignin. [4,[7][8][9] Varied experimental studies of PPE thermolysis have given rise to many proposed mechanisms. [7-10, 14-20, 23] At low temperatures (345-400 8C) and high concentrations, a free-radical chain reaction proceeds, [7,9] but at high temperatures (500-600 8C) and low concentrations, which is also known as flash vacuum photolysis (FVP), unimolecular reactions are observed (no radical chain reactions are present at low pressures).…”

“…[4,[7][8][9] Varied experimental studies of PPE thermolysis have given rise to many proposed mechanisms. [7-10, 14-20, 23] At low temperatures (345-400 8C) and high concentrations, a free-radical chain reaction proceeds, [7,9] but at high temperatures (500-600 8C) and low concentrations, which is also known as flash vacuum photolysis (FVP), unimolecular reactions are observed (no radical chain reactions are present at low pressures). [7,8] Computational studies have begun to provide insight into individual reaction steps, as well as substituent effects, that would be challenging experimentally.…”