Alkaline Hydrogenation Pulping

The effect of penetrant activity and temperature on the anomalous diffusion of hydrocarbons and solvent crazing in polystyrene part I: Biaxially oriented polystyrene

“…Since the equilibrium penetrant concentration monotonically affects the relaxation controlled transport process, the decreasing equilibrium concentration, which corresponds to the rising temperature and decreasing activity leads to an apparent negative temperature dependence of the overall sorption process. Similar results have been reported for the permeation of isobutylene and methyl bromide in polyethylene (8). In addition to the drop in sorption rate with the increasing temperature and dropping concentration, a change in the transport mechanism is characterized by the value of the exponent, n, for the relationship:…”

“…The activity dependence of the activation energy for pure Fickian diffusion contrasts sharply with these results. The activation energy for Fickian diffiision decreases sharply as the activity of penetrating organic molecules is increased ( 8 ) . These results simply reflect the effects of increased penetrant concentration on the segmental mobility of the polymeric matrix.…”

Guidelines for performing lignin-first biorefining

“…It should be noted that RCF carried out under H 2 pressure was first practiced/developed in the late 1930s and 1940s as a methodology to study lignin, [51][52][53][54][55][56][57] and as a means for pulping and high-yield production of lignin-based chemicals, but this was not commercialized at the time. [58][59][60][61] Variants of the RCF approach include systems in which sugars in the biomass operate as reducing agents, 62 and recently flowthrough operations or catalyst baskets have been applied such that biomass solvolysis and hydrogenation/hydrogenolysis reactions on lignin intermediates have been separated in time and space. [63][64][65][66][67] The primary roles of the metal catalyst are reductive stabilisation of reactive intermediates from lignin that result from the solvolysis process and depolymerisation of the solubilised lignin oligomers.…”

“…2). 58,68 The solvent determines not only the delignification degree (i.e., solvolysis and extraction of lignin) but also the retention of (hemi-)cellulose as a pulp, as well as the selectivity and distribution of monophenolics. 38 Usage of water, or protic solvents with a high proportion of water, may produce high delignification but will also hydrolyse and solubilise carbohydrates, which can be hydrogenated by the catalyst or react with the solvent.…”

Reductive Catalytic Fractionation of Wheat Straw Biomass

“…The first studies on the catalytic hydrogenolysis and hydrogenation of woody biomass date back to the 1940s, when this method was employed as a means to explore the chemical structure of lignin. , At that time, the hydrogenation of wood was also proposed as a pulping method, , but it was only in the 2010s that the RCF concept took the spotlight as a means to develop integrated biorefineries. − Although several breakthroughs were made since then, paving the way for the industrial application of the RCF, , the majority of these studies have been chiefly focused on the treatment of woody biomass, while less attention was given to the fractionation of herbaceous feedstocks. In general, the latter have lower lignin contents and a higher fraction of G- and H-lignin units, more prone to undergo recondensation, which pose a limitation to the formation of low-MW phenolics that can be attained via RCF.…”