The influence of oxygen (0–50 bar) on the molar mass and composition of hemicelluloses after hydrothermal treatment of spruce chips was studied in a batch reactor setup at 130 °C–160 °C. Purified galactoglucomannan was studied as a reference. The dissolved oxygen enhanced significantly the depolymerization of hemicelluloses from over 15,000 g/mol to 180 g/mol (monomers) as well as promoted acids formation from the monosaccharides. About 2–3 times faster depolymerization was observed already with rather low amounts of oxygen (2–8 bar), while the kinetics of depolymerization was significantly slower in inert atmosphere. The decrease in pH from neutral to as low as 2.5 lead to an autocatalytic effect on the polysaccharide hydrolysis and the consecutive reactions of monosaccharides. The results emphasize the importance of performing hydrothermal treatment under inert atmosphere if large polymeric hemicellulsoses are desired or if monosaccharides are targeted in hydrolysis of hemicelluloses. If autocatalysis begins, it is difficult to stop.

在 130 °C–160 °C 的间歇式反应器装置中研究了氧气（0–50 bar）对云杉木片水热处理后半纤维素的摩尔质量和组成的影响。研究了纯化的半乳葡甘聚糖作为参考。溶解氧显着增强了半纤维素从超过 15,000 g/mol 到 180 g/mol（单体）的解聚，并促进了单糖的酸形成。已经观察到在相当低的氧气量（2-8 bar）下解聚快了大约 2-3 倍，而在惰性气氛中解聚动力学明显较慢。pH从中性降低至低至2.5导致对多糖水解和单糖连续反应的自催化作用。结果强调了如果需要大的聚合半纤维素或如果在半纤维素的水解中以单糖为目标，则在惰性气氛下进行水热处理的重要性。如果自催化开始，就很难停止。