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51.
52.
Peroxides play an i mportant role in atmosphericchemistry,because they are not only amongthe prin-ciple oxidants in the chemical conversion of O3andSO2,but also act as an atmospheric sink and tempo-rary reservoir for i mportant oxidizing radicals such asOH, HO2and RO2[1 ,2]. With the development ofmeasurement techniques , several organic peroxideswere identified in the atmosphere in addition to hy-drogen peroxide (H2O2)[3—5]. And among these or-ganic peroxides , methyl hydroperoxide ( MH… 相似文献
53.
Methyl hydroperoxide (CH3OOH, MHP) is known to be a significant sink and reservoir of HOx and ROx radicals in the atmosphere. In order to investigate the impact of MHP on the concentration of atmospheric OH radicals, two key gas-phase reactions of MHP, i.e. the reactions with OH radicals and with UV photolysis, have been simulated at temperature of 293±2 K and total pressure of 1.01×105 Pa, using the long path Fourier transform infrared (LP-FTIR) spectrometry. OH radicals are generated by the photolysis of O3 in the presence of water vapor. Combined with the relative rate method, the reaction rate constant of MHP with OH radicals is determined to be (3.99±0.15)×10-12 cm3?molecule-1?s-1, and thus the atmospheric lifetime of MHP is estimated at 2.9 days. Furthermore, from detailed analysis of the UV photolysis of MHP, the yield of OH radicals is obtained to be 0.91±0.04. Based on the MHP atmospheric lifetime and the yield of OH radicals, it is concluded that MHP plays an essential role in the redistribution of OH radicals in the troposphere. 相似文献
54.
Various intermediates of hydroperoxide activation on Ti-containing microporous and mesoporous silicates were studied using the DFT cluster model approach. Lowering the coordination number of Ti(IV) ions in the matrix was found to destabilize the peroxide form =Ti(OO) and to hinder the formation of singlet dioxygen. 相似文献
55.
《Journal of Dispersion Science and Technology》2013,34(3-4):607-613
Abstract Functional latexes with poly(methyl methacrylate) (PMMA) cores and amino‐containing, water‐soluble polymer shells were synthesized via direct graft copolymerization of methyl methacrylate from water‐soluble polymers induced by a small amount of tert‐butyl hydroperoxide (TBHP) at 80°C for 2 h. Amphiphilic graft copolymers and PMMA homopolymers were generated concurrently to form highly monodispersed latexes. The effects of water‐soluble polymer containing different amino group, reaction temperature, TBHP concentration, molecular weight of the polymer and pH of the solution on conversion and grafting efficiency of the monomer and particle size were investigated. Transmission electron microscopic images of the PMMA/poly(ethyleneimine) (PEI) and PMMA/poly(allylamine) (PAA) particles clearly show well‐defined core‐shell morphologies, where PMMA cores are coated with either PEI or PAA shell. The amino‐containing polymer shells were also confirmed with zeta‐potential measurements. Furthermore, the amino‐containing latexes can be produced with a solids content up to 22 wt.%. Thus, this method provides a commercially viable route to functional latexes. 相似文献
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57.
流动注射分析法已发展成为一个很好的分析手段和一种很有用的测定方法。本文讨论应用碘量法来进行流动分析测试。用H_2SO_4和KI与H_2O_2反应,在420nm处测其吸光度。每个试样均有重现形状的单峰出现。在进样后30 s就可读出数据。其最低检出限量为1μg,工作曲线呈现极好的重现性。所得结果稳定,其相关系数超过0.9993,与KMnO_4法相比,其相对误差小于2.5%。同时,对某些分析条件,诸如H_2SO_4和KI的流速、样品用量、反应管长等因素进行了探讨。 相似文献
58.
Decomposition of alkyl hydroperoxide by a copper(I) complex: insights from density functional theory
Yi Luo 《Tetrahedron letters》2008,49(48):6841-6845
The B3LYP theory and scaled hypersphere search method are utilized to explore pathways of (HO)2PS2Cu-mediated CH3OOH decomposition, a model reaction of alkyl hydroperoxide with cuprous dialkyldithiophosphate [(RO)2PS2Cu]. It is found that the decomposition of CH3OOH mediated by the copper(I) complex may lead to formaldehyde and water molecules via O-O bond heterolysis and subsequent intramolecular hydrogen transfer, with retainment of the copper(I) complex. The subsequent hydrogen transfer event and formation of water may add new understanding to the (RO)2PS2Cu-mediated decomposition process of alkyl hydroperoxide. The oxygen transfer from CH3OOH to (HO)2PS2Cu moiety, as an O-O bond cleavage manner of CH3OOH, is also found to occur. 相似文献
59.
以油溶性过氧化羟基异丙苯(CHP)为氧化剂,Al2O3为催化剂,引入超声作用,以正辛烷为模拟油品对油中二苯并噻吩的氧化进行了研究。考察了反应温度、反应时间、催化剂用量、氧硫比、超声功率对二苯并噻吩(DBT)降解率的影响并进行了正交实验,结果表明,各因素影响程度大小依次为:反应温度>催化剂用量>超声功率>反应时间>氧硫比,在反应温度为70℃,反应时间为45 min,氧硫比为5:1,催化剂用量为0.3 g,超声功率为60 W的最佳氧化条件下,DBT的降解率达到了88.0%。 相似文献
60.
Trieu-Tien Thai 《Journal of organometallic chemistry》2011,696(21):3285-3291
Arene ruthenium complexes [(η6-arene)Ru(sacc)2(OH2)] (arene = para-cymeme, benzene) containing an aqua and two saccharinato ligands have been synthesized from [(η6-arene)RuCl2]2 and sodium saccharinate in a water-ethanol mixture (1:1). The aqua complex [(η6-MeC6H4Pri)Ru(sacc)2(OH2)] reacts with acetonitrile to give the acetonitrile complex [(η6-MeC6H4Pri)Ru(sacc)2(NCMe)]. The corresponding benzene derivative [(η6-C6H6)Ru(sacc)2(NCMe)] was obtained from [(η6-C6H6)RuCl2]2 and saccNa in an acetonitrile-methanol mixture (1:1). All new complexes show a piano-stool geometry with two mono-hapto nitrogen-bonded saccharinato ligands in addition to a H2O or MeCN ligand. All complexes of the type [(η6-arene)Ru(sacc)2(OH2)] and [(η6-arene)Ru(sacc)2(NCMe)] were found to catalyze the oxidation of secondary alcohols with tert-butyl hydroperoxide (ButOOH) to give the corresponding ketones in aqueous solution. 相似文献