Supplementary data for the mechanism research for depolymerization of cellulose induced by hydroxyl radical using GC-MS, reaction kinetics simulation and quantum chemistry computation.

This data article contains the chemical structure of cellobiose, which was chosen as the model molecule of cellulose. A brief diagram of the reaction system established by Packmol containing celluloses, hydroxyl radicals and water for ReaxFF kinetic simulation as well as the energy change curve obtained during the optimization process were provided. The total ion current (TIC) and product species of the reaction of cellobiose with Fenton's regent given by GC-MS were displayed, respectively. A brief diagram of the OH-abstraction of cellobiose triggered by hydrated hydrogen radical was shown. Additionally, chemical structures of all transition states in pathways 1-4 of the reaction of cellobiose with •OH carried out by means of quantum calculation using Gaussian 09 are shown. Some key frames in reaction pathway 1 obtained by ReaxFF simulation and the thermodynamic parameters for reaction pathways 1-4 were also listed successively. Interpretation of this data can be found in a research article titled "Study on Cellulose Degradation Induced by Hydroxyl Radical with Cellobiose as a Model Using GC-MS, ReaxFF Simulation and DFT Computation" (Shao et al., 2020) [1].

Study on cellulose degradation induced by hydroxyl radical with cellobiose as a model using GC-MS, ReaxFF simulation and DFT computation.

The OH induced cellulose degradation was examined by analyzing the reaction products of Fenton's regents with cellobiose. Many degradation products including C2-C5 compounds such as oxaldehyde, malonaldehyde and 2-hydroxysuccinaldehyde were detected by GCMS analysis. Four reaction pathways for the formation of some degradation products were obtained from ReaxFF kinetics simulation and validated by the DFT quantum chemistry calculation at B3LYP/6-31+g(d,p) level. It was found that the H-abstraction from OH of the glucose unit by OH can cause saccharide ring open and breakage of the glycosidic bond. Pathways 1-4 showed that the glucose unit can react with OH consecutively to produce small molecular products with carbon atoms less than 6. This study indicated that ReaxFF reaction kinetics is a powerful tool for the exploration of the degradation mechanism of cellulose induced by OH at room temperature, which correlated well with the experimental results and was validated by DFT calculation.

Preparation and Characterization of Acylcaramel.

Caramel is a widely used water-soluble food pigment. The acylation of caramel was conducted by aliphatic acyl chlorides with different chain lengths. Acetyl, butyryl, octyl, lauryl, palmityl, and stearyl caramels were prepared with the ratio of acyl chloride/caramel of 6. The formation of acylated caramel was confirmed by Fourier transform infrared spectra, and the acyl mass fraction in acylcaramel was determined by potentiometric titration. Thermal analysis showed that the weight loss of acylated caramel was higher than that of raw caramel. The scanning electron microscopy analysis showed that the morphology of acylated caramel was significantly different from that of raw material. The acyl mass fraction of acylated caramel increased with the increase of acyl chain lengths. Meanwhile, the lipo-hydro partition coefficient, the solubility in corn oil, and color, red, and yellow indexes increased with the increase of the mass fraction of acyl in acylcaramel. It was found that stearyl caramel has the highest lipid solubility of 5.73 mg/mL in corn oil; however, the color, red, and yellow indexes of palmityl caramel reached 25 818.60, 1.149, and 1.757, respectively. This study provides a method to improve the solubility of caramel in lipid phase and expand the application range of caramel.