Systematic studies of the thermal decomposition mechanism of benzoyl peroxide(BPO) in ground state, leading to various intermediates, products and the potential energy surface(PES) of possible dissociation reactions w...Systematic studies of the thermal decomposition mechanism of benzoyl peroxide(BPO) in ground state, leading to various intermediates, products and the potential energy surface(PES) of possible dissociation reactions were made computationally. The structures of the transition states and the activation energies for all the paths causing the formation of the reaction products mentioned above were calculated by the AM1 semi-empirical method. This method is shown to to be one predict correctly the preferred pathway for the title reaction. It has been found that in ground state, the thermal decomposition of benzoyl peroxide has two kinds of paths. The first pathway PhC(O)O-OC(O)Ph→PhC(O)O · →Ph · +CO 2 produces finally phenyl radicals and carbon dioxide. And the second pathway PhC(O)OO-C(O)Ph→PhC(O)OO · +PhC(O) · → PhC(O) · +O 2 →Ph · +CO+O 2, via which the reaction takes place only in two steps, produces oxygen and PhC(O) · radicals, and the further thermal dissociation of PhC(O) · is quite difficult because of the high activation energy in ground state. The calculated activation energies and reaction enthalpies are in good agreement with the experimental values. The research results also show that also the thermal dissociation process of the two bonds or the three bonds for the benzoyl peroxide doesn′t take place in ground state.展开更多
Three crystal architectures, including one organic compound of benzoyl peroxide（Ⅰ） and two clusters of tri-iron（Ⅲ） and bi-cupper（Ⅱ） with benzoic ligands（2 and 3）, were self-assembled by an in situ redox way...Three crystal architectures, including one organic compound of benzoyl peroxide（Ⅰ） and two clusters of tri-iron（Ⅲ） and bi-cupper（Ⅱ） with benzoic ligands（2 and 3）, were self-assembled by an in situ redox way of benzoyl peroxide oxidants reacting with Mo, Fe and Cu powders, respectively. X-ray crystallographic results show that both the asymmetry tri-iron（Ⅲ） cluster and the benzoylperoxide crystal architecture（2 and 1） with complicated 3D networks were constructed by intermolecular hydrogen-bonding interactions. Contrarily, the symmetrical bi-copper（Ⅱ） cluster crystal architecture（3）, only with π-π stacking between paralleled phenyl groups and without any intermolecular hydrogen-bonding interactions, only presented an 1D zigzag chain along the a-axis.展开更多
The effect of benzoyl peroxide （BPO） on polypropylene （PP） degradation in supercritical water was investigated with the aim of developing a process for recycling of waste plastics. A series of experiments with and...The effect of benzoyl peroxide （BPO） on polypropylene （PP） degradation in supercritical water was investigated with the aim of developing a process for recycling of waste plastics. A series of experiments with and without BPO were carried out at temperatures of 653 K and 673 K under pressure about 26 MPa for 30, 75 and 120 min respectively. Products were analyzed by an Ostward-type viscometer, gas chromatography and spectrometry （GC/MS） etc. The results indicated that mean molecular weight of the samples decreased greatly along with the time elapsing or with the temperature increasing, and PP was decomposed to Miphatic and cycloparaftinic hydrocarbons but a few benzenoid hydrocarbons. By comparing the experiments with and without BPO, it was made clear that BPO is an effective additive on PP degradation in supercritical water.展开更多
以甲基丙烯酸甲酯(MMA)为单体、过氧化苯甲酰(BPO)和N,N-二甲基苯胺(DMA)组成的氧化-还原体系为引发剂,采用85℃预聚、24℃后聚和120℃处理工艺进行自由基本体聚合制备了聚甲基丙烯酸甲酯(PMMA)。研究DMA用量、BPO与DMA配比对PMMA透光...以甲基丙烯酸甲酯(MMA)为单体、过氧化苯甲酰(BPO)和N,N-二甲基苯胺(DMA)组成的氧化-还原体系为引发剂,采用85℃预聚、24℃后聚和120℃处理工艺进行自由基本体聚合制备了聚甲基丙烯酸甲酯(PMMA)。研究DMA用量、BPO与DMA配比对PMMA透光率、硬度、强度和热分解温度的影响。研究发现,DMA可明显改善PMMA的力学性能和热学性能,降低其透光率,但不影响透明度。结果表明,当DMA用量3%、BPO与DMA配比0.53∶1时,PMMA硬度为94HD、抗弯强度为66.8 MPa、冲击强度为13.2 k J/m2、初始分解温度为273℃、结束分解温度为404.8℃,380～800 nm的平均透光率为82%以上,综合性能最优。并应用设定的聚合工艺和优化的配方,在低温低压条件下,制备出微米孔结构PMMA,为聚合物微发泡提供了一种新的制备方法。展开更多
Objective:Combination therapy is currently the preferred acne treatment.We conducted this study to compare the efficacy and tolerability of 0.1%adapalene with 1%clindamycin versus 0.1%adapalene with 2.5%benzoyl peroxi...Objective:Combination therapy is currently the preferred acne treatment.We conducted this study to compare the efficacy and tolerability of 0.1%adapalene with 1%clindamycin versus 0.1%adapalene with 2.5%benzoyl peroxide(BPO)in the treatment of acne vulgaris.Methods:This study was conducted over a period of 1 year from September 2014 to September 2015.One-hundred patients aged 14 to 30 years with mild to moderate acne vulgaris were included.The patients were randomly allocated to 2 equal groups(n=50 in each group),and received a topical combination of 0.1%adapalene with 1%clindamycin andtopical combination of 0.1%adapalene with 2.5%BPO,respectively).The efficacy and tolerability of two treatments were compared.The unpaired studentt test was used to compare the difference in continuous variables between 2 groups,while the chi-square test or Fisher exact test was used for categorical variables.Results:One-hundred patients with mild to moderate acne vulgaris were randomly allocated to 2 equal groups(n=50 in each group).After 12 weeks of treatment,there were no significant differences between the adapalene-clindamycin and adapalene-BPO in the mean reductions in the numbers of non-inflammatory lesions(11.16±8.01 and 11.12±8.62,respectively),inflammatory papules(49.78±37.57 and 50.48±36.57,respectively),and total lesions(67.50±44.59 and 70.12±46.83,respectively).The incidence of a burning sensation was significantly greater in the adapalene-BPO group than the adapalene-clindamycin group(32%vs.6%;P=0.002).Conclusion:Topical adapalene plus clindamycin and adapalene plus BPO had similar efficacies in the treatment of acne.Adapalene with clindamycin was better tolerated than adapalene with BPO.展开更多
基金Supported by National NaturalScienceFoundation of China( No.2 97730 0 7) and the NaturalScienceFoundation of Qu-jing Normal College( No.2 0 0 0 0 9)
文摘Systematic studies of the thermal decomposition mechanism of benzoyl peroxide(BPO) in ground state, leading to various intermediates, products and the potential energy surface(PES) of possible dissociation reactions were made computationally. The structures of the transition states and the activation energies for all the paths causing the formation of the reaction products mentioned above were calculated by the AM1 semi-empirical method. This method is shown to to be one predict correctly the preferred pathway for the title reaction. It has been found that in ground state, the thermal decomposition of benzoyl peroxide has two kinds of paths. The first pathway PhC(O)O-OC(O)Ph→PhC(O)O · →Ph · +CO 2 produces finally phenyl radicals and carbon dioxide. And the second pathway PhC(O)OO-C(O)Ph→PhC(O)OO · +PhC(O) · → PhC(O) · +O 2 →Ph · +CO+O 2, via which the reaction takes place only in two steps, produces oxygen and PhC(O) · radicals, and the further thermal dissociation of PhC(O) · is quite difficult because of the high activation energy in ground state. The calculated activation energies and reaction enthalpies are in good agreement with the experimental values. The research results also show that also the thermal dissociation process of the two bonds or the three bonds for the benzoyl peroxide doesn′t take place in ground state.
基金Supported by the National Natural Science Foundation of China(No.20771073)
文摘Three crystal architectures, including one organic compound of benzoyl peroxide（Ⅰ） and two clusters of tri-iron（Ⅲ） and bi-cupper（Ⅱ） with benzoic ligands（2 and 3）, were self-assembled by an in situ redox way of benzoyl peroxide oxidants reacting with Mo, Fe and Cu powders, respectively. X-ray crystallographic results show that both the asymmetry tri-iron（Ⅲ） cluster and the benzoylperoxide crystal architecture（2 and 1） with complicated 3D networks were constructed by intermolecular hydrogen-bonding interactions. Contrarily, the symmetrical bi-copper（Ⅱ） cluster crystal architecture（3）, only with π-π stacking between paralleled phenyl groups and without any intermolecular hydrogen-bonding interactions, only presented an 1D zigzag chain along the a-axis.
基金Supported by the National Natural Science Foundation of China (No.59972022).
文摘The effect of benzoyl peroxide （BPO） on polypropylene （PP） degradation in supercritical water was investigated with the aim of developing a process for recycling of waste plastics. A series of experiments with and without BPO were carried out at temperatures of 653 K and 673 K under pressure about 26 MPa for 30, 75 and 120 min respectively. Products were analyzed by an Ostward-type viscometer, gas chromatography and spectrometry （GC/MS） etc. The results indicated that mean molecular weight of the samples decreased greatly along with the time elapsing or with the temperature increasing, and PP was decomposed to Miphatic and cycloparaftinic hydrocarbons but a few benzenoid hydrocarbons. By comparing the experiments with and without BPO, it was made clear that BPO is an effective additive on PP degradation in supercritical water.
文摘以甲基丙烯酸甲酯(MMA)为单体、过氧化苯甲酰(BPO)和N,N-二甲基苯胺(DMA)组成的氧化-还原体系为引发剂,采用85℃预聚、24℃后聚和120℃处理工艺进行自由基本体聚合制备了聚甲基丙烯酸甲酯(PMMA)。研究DMA用量、BPO与DMA配比对PMMA透光率、硬度、强度和热分解温度的影响。研究发现,DMA可明显改善PMMA的力学性能和热学性能,降低其透光率,但不影响透明度。结果表明,当DMA用量3%、BPO与DMA配比0.53∶1时,PMMA硬度为94HD、抗弯强度为66.8 MPa、冲击强度为13.2 k J/m2、初始分解温度为273℃、结束分解温度为404.8℃,380～800 nm的平均透光率为82%以上,综合性能最优。并应用设定的聚合工艺和优化的配方,在低温低压条件下,制备出微米孔结构PMMA,为聚合物微发泡提供了一种新的制备方法。
文摘Objective:Combination therapy is currently the preferred acne treatment.We conducted this study to compare the efficacy and tolerability of 0.1%adapalene with 1%clindamycin versus 0.1%adapalene with 2.5%benzoyl peroxide(BPO)in the treatment of acne vulgaris.Methods:This study was conducted over a period of 1 year from September 2014 to September 2015.One-hundred patients aged 14 to 30 years with mild to moderate acne vulgaris were included.The patients were randomly allocated to 2 equal groups(n=50 in each group),and received a topical combination of 0.1%adapalene with 1%clindamycin andtopical combination of 0.1%adapalene with 2.5%BPO,respectively).The efficacy and tolerability of two treatments were compared.The unpaired studentt test was used to compare the difference in continuous variables between 2 groups,while the chi-square test or Fisher exact test was used for categorical variables.Results:One-hundred patients with mild to moderate acne vulgaris were randomly allocated to 2 equal groups(n=50 in each group).After 12 weeks of treatment,there were no significant differences between the adapalene-clindamycin and adapalene-BPO in the mean reductions in the numbers of non-inflammatory lesions(11.16±8.01 and 11.12±8.62,respectively),inflammatory papules(49.78±37.57 and 50.48±36.57,respectively),and total lesions(67.50±44.59 and 70.12±46.83,respectively).The incidence of a burning sensation was significantly greater in the adapalene-BPO group than the adapalene-clindamycin group(32%vs.6%;P=0.002).Conclusion:Topical adapalene plus clindamycin and adapalene plus BPO had similar efficacies in the treatment of acne.Adapalene with clindamycin was better tolerated than adapalene with BPO.
