Papers by Keyword: Adipic Acid

Abstract: Polypropylene (PP) membranes were respectively prepared using adipic acid (APA) and Sorbitol (NA-40) as nucleating agent via thermally induced phase separation (TIPS) method. The effects of nucleating agent content and cooling temperature on the structure and performance of membrane were investigated using scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). WAXD spectrogram indicates that three kinds of α, β and γ-form crystal were formed in this preparation process and the relative content of β-form crystal in membrane prepared by NA-40 system is higher than that of membrane formed by adipic acid. SEM images show that porous structure and cellular structure were observed on the surface and cross-section of membrane. The water flux, tensile strength and elongation increase with the addition of nucleating agent content and decrease with cooling temperature rising. This paper aims to choose proper nucleating agent NA-40 and coagulation temperature to improve the properties of PP membranes.

Abstract: A new environmental friendly catalyst, H₄SiW₆Mo₆O₄₀/TiO₂-SiO₂ was prepared by impregnation method, the synthesis of cyclohexanone 1,2-propanediol ketal was the probe reaction to optimize the synthetic condition of catalyst. The reactive condition of catalyst was optimized by orthogonal test method. The optimum conditions are n (TiO₂): n (SiO₂)= 3: 1, 20 % mass ratio of m (H₄SiW₆Mo₆O₄₀): m (TiO₂-SiO₂), the calcined time is 3 h and 300 °C of activated temperature. Using H₄SiW₆Mo₆O₄₀/TiO₂-SiO₂ as catalyst, adipic acid was synthesized from the oxidation of cyclohexanone by 30 % H₂O₂. Influences of dosage of H₄SiW₆Mo₆O₄₀/TiO₂-SiO₂, reaction temperature, volume of hydrogen peroxide and reaction time were discussed. Experimental results showed that H₄SiW₆Mo₆O₄₀/TiO₂-SiO₂ is a good catalyst for synthesis of adipic acid. When n (cyclohexene): n (H₂O₂): n (H₄SiW₆Mo₆O₄₀/TiO₂-SiO₂)= 100: 979: 0.04, reaction temperature is 130 °C and reaction time is 5 h, under the optimum conditions, the yield of adipic acid is 45.9 %.

Abstract: A new route to substitute for the traditional two-step method for adipic acid production has been investigated. Supported nano metal catalysts Au/C and Co/C were prepared and used for liquid phase oxidation of cyclohexane to adipic acid with oxygen as an oxidant. These catalysts were characterized by XRD, TEM and ICP-AES. The reactions were carried out in an autoclave with solvent and radical initiator at 373~423K and 1.5 MPa. Au/C (1.25%) was found to be a highly efficient catalyst for the oxidation of cyclohexane with a high conversion (44.93%) of cyclohexane and more than 54.85% selectivity to adipic acid. It is indicated that there was a potential application prospect for the nano-catalysts in one-step oxidation of cyclohexane to adipic acid.

Abstract: Using aqueous hydrogen peroxide solution (30wt%) as oxidant, potassium bisulfate (KHSO₄) as acid ligand, adipic acid was synthesized with cyclohexanone as raw material and H₄SiW₆Mo₆O₄₀/SiO₂ as catalyst. The factors influencing the synthesis were discussed and the best reaction conditions were found out. Experimental results showed that H₄SiW₆Mo₆O₄₀/SiO₂ is an excellent catalyst. The optimal conditions are: n (cyclohexanone):n (H₂O₂)=1:4.0,catalyst dosage is 0.4g, mass of acidic ligands is 0.1g, and the reaction time is 4 h, the yield of adipic acid can reach 93.7 %.

Abstract: A novel catalyst, H₃PW₆Mo₆O₄₀/SiO₂ was prepared by a sol-gel technique, and characterized by FT-IR and XRD. Using aqueous hydrogen peroxide solution (30wt%) as oxidant, sodium bisulfate (NaHSO₄) as acid ligand, adipic acid was synthesized with cyclohexanone as raw material and H₃PW₆Mo₆O₄₀/SiO₂ as catalyst. The factors influencing the synthesis were discussed and the best reaction conditions were found out. Experimental results showed that H₃PW₆Mo₆O₄₀/SiO₂ is an excellent catalyst. When n (cyclohexanone):n (H₂O₂) : n (H₃PW₆Mo₆O₄₀/SiO₂):n (NaHSO₄) = 100:440.7:0.21:0.74, reaction temperature is 90°C and reaction time is 6 h, the yield of adipic acid can reach 90.2%.

Abstract: Ammonium Phosphomolybdate with Dawson structure was prepared by hydrothermal synthesis and characted by means of FT-IR, UV-Vis,XRD and SEM. The synthesis of adipic acid with cyclohexanone and 30 percent hydrogen peroxide under microwave irradiation was carried out as a probe reaction to study the catalytic activity. Effects of catalyst amount,30wt.% H₂O₂ amount,microwave power, reaction time were investigated and optimized with orthogonal experiments and simple fact experiments. The results show that under the optimal condition, i.e. the mole ratio of C₆H₁₀O: H₂O₂:H₂C₂O₄•2H₂O:(NH₄)₆P₂Mo₁₈O₆₂•nH₂O =100:500:2.0:0.087, the reaction temperature was 100°C, microwave power was 400W, irradiation time was 3.5 h，the isolated yield of adipic acid could reach 72.5%．The catalyst could be reused for 5 times and the isolated of adipic acid was still above 43.2%.

Abstract: W-SBA-15 mesoporous material was synthesized by using a one-step co-condensation sol-gel process and characterized by various methods. The results showed that the prepared W-SBA-15 sample retained the typical mesoporous structure of SBA-15 and exhibited good catalytic performance for the green synthesis of adipic acid under organic solvent-free conditions.

Abstract: HPW/C catalysts were prepared using impregnation method. The physical chemistry properties of the catalysts were characterized employing XRD and NH₃-TPD.The effects of HPW loading, catalyst amount and reaction time on the catalyst performances were investigated. The results more acid content and active center contribute to the reaction performance. Under the optimal reaction conditions of 0.8g 29%(w) HPW/C as the catalyst, n(adipic acid): n(ethanol):n(toluene)=1:6:1,5h,the etherification rate was 97.3%.

Abstract: Zn-Al hydrotalcite exhibited fluorescence property without fluorescent substances intercalation. Its maximum excitation wavelength was 406nm and maximum emission wavelength was 523nm. In this study citric acid and adipic acid were introduced into the interlayer of LDH, which enlarged the interlayer spacing. It was found that the fluorescence property was influenced by anions in the interlayer of hydrotalcites. And it would be favorable to bind with other organic compounds to get photocatalysis materials for citric acid modified Zn-Al hydrotalcite. Meanwhile, the fluorescence intensity was enhanced greatly after modified by adipic acid, so it could be used as photocatalyst precursors.