Lilac-based lignin is an important lignin. Most of the natural lignins are connected through β-O-4 bonds to form a reticular structure. β-O-4-type lilac-based lignin dimeric modulators are closer to the actual lilac-based lignin structure, as multiple methoxy groups were added to it on the basis of the modulators studied by the previous researchers. In the Dmol³ module of the software Materials Studio 2019, the pyrolysis reaction paths of β-O-4 lilac-based lignin dimer modulators were simulated based on the density flooding theory using the B3LYP hybridization flooding at 875 K and 101 kPa. The enthalpy values of the reactants and products were calculated for each step of the reaction, and the frequency analysis was carried out by the Vibration Analysis module to confirm that there were only real frequencies and no imaginary frequencies; the enthalpy change of each step of the reaction was calculated and the total enthalpy change of the reaction paths was compared. The smaller the total enthalpy change was, the easier the paths were to take place thermodynamically, and then the more advantageous reaction paths were obtained to get the pyrolysis products of the corresponding paths finally. The results show that the initial pyrolysis of β-O-4 lilac-based lignin dimer modulators at 875 K and 101 kPa is more likely to involve the breakage of the C_α—C_β bond and the β-O-4 bond, among which the breakage of the β-O-4 bond is the most likely to occur. The more favorable reaction paths include R4 with a total enthalpy change of-59.65 kJ/mol, R10 with a total enthalpy change of-219.44 kJ/mol, R12 with a total enthalpy change of-14.93 kJ/mol, R21 with a total enthalpy change of-389.29 kJ/mol, R23 with a total enthalpy change of-466.24 kJ/mol, and R24 with a total enthalpy change of-276.72 kJ/mol, with the most favorable paths being R21, R23 and R24. The main products of pyrolysis are o-benzenetriol, 3,4,5-trihydroxybenzyl alcohol, 3,4,5-trihydroxybenzaldehyde and ethanol, among which o-benzenetriol, 3,4,5-trihydroxybenzyl alcohol and ethanol are the pyrolysis products of R21, R23 and R24. The simulation results obtained in this study can lay the foundation for further simulation calculations for generating biomass coke.

LaCl₃ is one of the most promising hydrated salt thermochemical heat storage materials, and its reaction kinetics plays a crucial role in the study of its reaction characteristics. The study tested the reaction characteristics of dehydration and adsorption of LaCl₃ by experiments and analyzed the reaction kinetics mechanism. The dehydration process of LaCl₃·7H₂O at the heating rates of 1, 10 and 20 K/min was tested by a synchronous thermal analyzer. The results show that the dehydration process of LaCl₃·7H₂O can be divided into three stages, where 4,2 and 1 water molecules are removed respectively. The initial temperature of each stage is different at different heating rates. The activation energy value of three stages was calculated by FWO method and the activation energy of the first stage was the largest. The Doyle method was used to solve the mechanism functions of each stage, in which the first stage conforms to the shrinking cylinder model in the phase boundary reaction, while the second and the third stage conformed to the random nucleation and subsequent growth model. The adsorption process of LaCl₃ was tested at the temperature of 15, 20, 25, 30 ℃ and at the relative humidity of 40%, 60%, 80% by a constant temperature and humidity chamber. The adsorption reaction rate of LaCl₃ is positively correlated with the temperature and humidity. When the relative humidity is 40%, LaCl₃ does not decompose. The reaction rate of LaCl₃ is faster in the initial stage of the adsorption process. As the adsorption process proceeds, LaCl₃·nH₂O crystals formed on the surface restricts the contact between LaCl₃ and water vapor. The kinetic equation of LaCl₃ adsorption reaction was fitted, the adsorption process of LaCl₃ conformed to the chemical reaction series model, and the reaction order was 0.837. The results show that LaCl₃ has good chemical kinetics and high heat release, and is a potential chemical thermal storage material.