No abstract

Direct transformation of cellulose (PH101: DP∼200) into 5‐hydroxymethylfurfural (HMF) was investigated using the single CrCl3 or the combination of metal chlorides (CrCl3 with AlCl3, FeCl3, SnCl4, MnCl4, and CuCl2) in ionic liquid [Bmim]Cl under oil‐bath heating. As a result, a novel co‐catalysis CrCl3‐AlCl3 was determined to be the most efficient catalyst for the production of HMF. Compared with single CrCl3, the reaction time with CrCl3‐AlCl3 was reduced by nearly 1/3 when a similar HMF yield (58.3%) was obtained at 120 °C. Additionally, the catalytic mechanism of CrCl3‐AlCl3 was discussed. Furthermore, when celluloses with higher polymerization degree (filter paper: DP∼1500 and cotton: DP∼1950) were used, exceedingly higher yields of HMF (54.7% for filter paper and 59.5% for cotton) were obtained compared with previous work. This important result strongly indicates the general applicability of CrCl3‐AlCl3 for various kinds of natural cellulose with a huge range of DP.

A kind of form stable phase change material (PCM) based on expanded perlite, paraffin, urea formaldehyde hybrids is prepared by using vacuum-impregnation process. This kind of form stable PCM is made of paraffin as a dispersed phase change material and expanded perlite as a supporting material, and urea-formaldehyde resins as membrane materials to be applied to the porous surface of expanded perlite(EP). The structure of urea-formaldehyde resins(UF) being prepared is characterized by Fourier Transform Infrared Spectrophotometer(FT-IR). Hybrids’ thermal stability, latentheat and morphology are characterized by the thermogravimetry analysis(TGA), differential scanning calorimeter(DSC) Method and scanning electronic microscope(SEM), respectively. The FT-IR and SEM curves show that urea-formaldehyde resins have already been formed. The TGA analysis indicates that the form-stable phase change material has very good thermostability under working atmosphere. The application of DSC not only studies the appropriate curing time of UF，but also indicates that the form-stable PCM that has been prepared has more stable thermal energy storage performance than the traditional one.