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Background Prehydrolyzate, which is from the prehydrolysis process in dissolving pulps industry, contains various sugar-derived and lignin compounds such as xylooligosaccharides (XOS), gluco-oligosaccharides, xylose, glucose, and soluble lignin (S-L). The XOS has several beneficial effects on human physiology. XOS and S-L in prehydrolyzate are difficult to efficiently fractionate due to their similar molecular weights and water solubility. In this work, we proposed a sustainable and green process using polystyrene divinylbenzene (PS-DVB) resin to simultaneously separate and recover XOS and S-L. Enzymatic hydrolysis with endo-1,4-β-xylanase and fermentation with P. stipites were sequentially applied to purify XOS to minimize xylose content as well as amplify contents of xylobiose and xylotriose. In addition, 2D-HSQC NMR was used to analyze the structural characteristics of XOS and S-L. Furthermore, the biological abilities of antioxidants and prebiotics of these fractions were investigated by scavenging radicals and cultivating intestinally beneficial bacterias, respectively. Results Results showed that PS-DVB resin could simultaneously separate XOS and solubilized lignin with excellent yields of 93.2% and 85.3%, respectively. The obtained XOS after being purified by enzymatic hydrolysis and fermentation contained 57.7% of xylobiose and xylotriose. 10.4% amount of inherent xylan was found in the S-L fraction obtained by PS-DVB resin separation. 2D-HSQC NMR revealed that lignin carbohydrate complexes existed in both XOS and S-L as covalent linkages between lignin and 4- O -methylglucuronoarabinoxylan. The biological application results showed that the antioxidant capacity of S-L was stronger than XOS, while XOS was superior in promoting growth of intestinal Bifidobacteria adolescentis and stimulating production of short-chain fatty acids by Lactobacillus acidophilus. Conclusions The proposed strategy of sequentially combining hydrophobic resin separation, enzymatic hydrolysis, and fermentation was successfully demonstrated and resulted in simultaneous production of high-quality XOS and solubilized lignin. These biomass-derived products in prehydrolyzate can be regarded as value-adding prebiotics and antioxidants. Electronic supplementary material The online version of this article (10.1186/s13068-019-1527-3) contains supplementary material, which is available to authorized users.

Pipelining of heavy crudes can be facilitated by preparing oil-in-water (O/W) emulsions of the crude, but separation of the oil from the water after pipelining is problematic if conventional surfactants are used. Long-chain acetamidines are CO 2 -triggered switchable surfactants, being surface-active when CO 2 is present but not when CO 2 is absent. Unfortunately, in the presence of CO 2 , they stabilize water-in-oil (W/O) emulsions of heavy crude rather than the desired O/W emulsions. However, in the absence of added CO 2 , several compounds (Na 2 CO 3 , three of the long-chain acetamidines, and two other amidines) stabilize O/W emulsions. These low-viscosity emulsions can later be broken by the addition of CO 2 . The residual oil content in the recovered water is lowest if the compound used to stabilize the original emulsion was a long-chain acetamidine.

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The condensation of primary amine with N,N-dimethylacetamide dimethyl acetal yields a mixture of acetamidine and imidate ester. The product distribution in this reaction depends on the temperature, solvent, and structure of the primary amine. It is possible to suppress the formation of imidate ester by performing the reaction in the presence of excess dimethyl amine, yielding acetamidine as the exclusive product. For acetamidines that cannot be purified either by crystallization or distillation, this new method is necessary for the generation of pure acetamidines in good yields.

[reaction: see text] A highly effective direct coupling of acid chloride with terminal alkynes catalyzed by PdCl(2)(PPh(3))(2)/CuI together with a catalytic amount of sodium lauryl sulfate as the surfactant and K(2)CO(3) as the base provided ynones in high yields in water.