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1.
Vadim V. Krongauz John F. O’Connell Michael T. K. Ling 《Journal of Thermal Analysis and Calorimetry》2014,116(3):1285-1299
Kinetics of thermal and photo-oxidation of cumene in the absence of catalyst was studied using high-pressure differential scanning calorimetry and low-pressure photocalorimetry. Kinetics of oxidation was followed by cumene hydroperoxide (CHP), acetophenone, and phenol formation. The amount of CHP formed was deduced from the total heat of reaction of thermal degradation of CHP at 453 K and using a new gas chromatographic method. CHP solution in cumene oxidized at 453 K and 680 psi of oxygen reproducibly with the heat of reaction linearly dependent on peroxide concentration in cumene. It was confirmed that cumene thermal oxidation was slow at <453 K, but at ≥453 K could occur explosively. Autocatalysis by CHP during thermo-oxidation was confirmed. Apparent activation energy of the photo-oxidation of cumene was found to be E a = 22.3 kJ mol?1. The value corresponds to radical chain process of the cumene autoxidation. Under assumption of pseudo-first order reaction, the rate constant of CHP formation was found to change from k CHP ≈ 0.76 s?1 during the first 4 h of photo-oxidation to k CHP ≈ 0.2 s?1 at the later stages at 2.0 W cm?2 of UV exposure dose. It was established that the initial presence of the CHP in cumene does not change the photo-oxidation kinetics, but shifts the kinetic curve to earlier time. Finite difference method was employed to numerically model kinetics of cumene oxidation. The result indicated higher than expected thermal and photo-stability of both, cumene and CHP. 相似文献
2.
A protocol for the aerobic oxidation of cumene to cumene hydroperoxide (CHP) catalyzed by metalloporphyrins is reported herein. Typically, the reaction was performed in an intermittent mode under an atmospheric pressure of air and below 130°C. Several important reaction parameters, such as the structure and concentration of metalloporphyrin, the air flow rate, and the temperature, were carefully studied. Analysis of the data obtained showed that the reaction was remarkably improved by the addition of metalloporphyrins, in terms of both the yield and formation rate of CHP while high selectivity was maintained. It was discovered that 4 or 5 h was the optimal reaction time when the reaction was catalyzed by monomanganese-porphyrin ((p-Cl)TPPMnCl) (7.20 × 10?5 mol/l) at 120°C with the air flow rate being 600 ml/min. From the results, we also found that higher concentration of (p-Cl)TPPMnCl, longer reaction time and higher reaction temperature were all detrimental to the production of CHP from cumene. Studies of the reaction kinetics revealed that the activation energy of the reaction (E) is around 38.9 × 104 kJ mol?1. The low apparent activation energy of the reaction could explain why the rate of cumene oxidation to CHP in the presence of metalloporphyrins was much faster than that of the non-catalyzed oxidation. 相似文献
3.
采用共沉淀法制备了铜掺杂钙铝水滑石Ca4Cu x Al-LDHs(x=0,0.1,0.3,0.5,0.8,1.0),并对其催化异丙苯液相氧化制备异丙苯过氧化氢的活性进行了研究。采用X射线衍射、傅里叶红外光谱、扫描电子显微镜和热分析等手段对Ca4Cu x Al-LDHs进行了表征,制备的Ca4Cu x Al-LDHs保留了水滑石的片层状结构,铜的掺杂使孔径变小,比表面积增大。当进料比(催化剂/异丙苯)为7.5 mg/mL,反应温度85 ℃,氧气流速为15 mL/min,反应时间7 h,异丙苯的转化率为34.5%,异丙苯过氧化氢的选择性为86.9%,催化剂循环使用5次后,异丙苯的转化率为31.2%,异丙苯过氧化氢的选择性为83.3%。研究为异丙苯过氧化氢开发了新的催化体系。 相似文献
4.
Hazard evaluation for redox system of cumene hydroperoxide mixed with inorganic alkaline solutions 总被引:2,自引:2,他引:0
H. -Y. Hou Y. -S. Duh W. -L. Lee C. -M. Shu 《Journal of Thermal Analysis and Calorimetry》2009,95(2):541-545
In petrochemistry, dicumyl peroxide (DCPO) is used in various resins for improving physical properties, which was produced
by cumene hydroperoxide (CHP) with oxidization reaction, redox reaction, and dehydration reaction. The reactant, CHP, is a
typical organic hydroperoxide and has been intrinsically unstable and reactive due to its bivalent -O-O- structure which can
be broken readily with bond-dissociation energy. This sequence on sensitive study aimed at the thermal hazard evaluation for
the reactive and incompatible characteristics of CHP mixed with various inorganic alkaline solutions. Differential scanning
calorimetry (DSC) and vent sizing package 2 (VSP2) were used to analyze the thermal hazards and runaway reaction of redox
system, such as decomposition of CHP in cumene solution and CHP react with inorganic alkaline solutions, exothermic onset
temperature, peak power, heat of decomposition of dynamic scanning tests, adiabatic self-heating rate, pressure rise rate,
maximum temperature, maximum pressure of reaction system, etc. The results of the tests have proven helpful in establishing
safe handling, storage, transportation, and disposal guidelines. 相似文献
5.
J.-J. Peng S.-H. Wu H.-Y. Hou C.-P. Lin C.-M. Shu 《Journal of Thermal Analysis and Calorimetry》2009,96(3):783-787
Over 90% of the cumene hydroperoxide (CHP) produced in the world is applied in the production of phenol and acetone. The additional
applications were used as a catalyst, a curing agent, and as an initiator for polymerization. Many previous studies from open
literature have verified and employed various aspects of the thermal decomposition and thermokinetics of CHP reactions. An
isothermal microcalorimeter (thermal activity monitor III, TAM III), and a thermal dynamic calorimetry (differential scanning
calorimetry, DSC) were used to resolve the exothermic behaviors, such as exothermic onset temperature (T
0), heat power, heat of decomposition (ΔH
d), self-heating rate, peak temperature of reaction system, time to maximum rate (TMR), etc. Furthermore, Fourier transform
infrared (FT-IR) spectrometry was used to analyze the CHP products with its derivatives at 150 °C. This study will assess
and validate the thermal hazards of CHP and incompatible reactions of CHP mixed with its derivatives, such as acetonphenone
(AP), and dimethylphenyl carbinol (DMPC), that are essential to process safety design. 相似文献
6.
Cumene Liquid Oxidation to Cumene Hydroperoxide over CuO Nanoparticle with Molecular Oxygen under Mild Condition
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Meiying Zhang Lefu Wang Hongbing Ji Bing Wu Xiaoping Zeng 《天然气化学杂志》2007,16(4):393-398
CuO nanoparticle was synthesized via wet chemical method and was characterized by X-ray diffraction(XRD),nitrogen adsorption-desorption,and scanning electron microscopy(SEM).Catalytic oxidation of cumene with molecular oxygen was studied over CuO nanoparticle.The catalysts showed markedly higher activities as compared to CuO prepared by conventional method,CuO/Al_2O_3,or ho- mogeneous copper catalyst under comparable reaction conditions.The cumene conversion,comene hy- droperoxide(CHP)yield,and selectivity using 0.25 g CuO nanoparticle catalyst and 0.1 mol cumene at 358 K for 7 h were 44.2%,41.2% and 93.2%,respectively.The catalyst can be recycled.After 6 recycled experiments,no loss of catalytic activity was observed. 相似文献
7.
Utilization of microcalorimetry for an assessment of the potential for a runaway decomposition of cumene hydroperoxide at low temperatures 总被引:4,自引:4,他引:0
J. -R. Chen S. -H. Wu S. -Y. Lin H. -Y. Hou C. -M. Shu 《Journal of Thermal Analysis and Calorimetry》2008,93(1):127-133
The exothermic decomposition of cumene hydroperoxide (CHP) in cumene liquid was characterized by isothermal microcalorimetry,
involving the thermal activity monitor (TAM). Unlike the exothermic behaviors previously determined from an adiabatic calorimeter,
such as the vent sizing package 2 (VSP2), or differential scanning calorimetry (DSC), thermal curves revealed that CHP undergoes
an autocatalytic decomposition detectable between 75 and 90°C. Previous studies have shown that the CHP in a temperature range
higher than 100°C conformed to an n
th order reaction rate model. CHP heat of decomposition and autocatalytic kinetics behavior were measured and compared with
previous reports, and the methodology and the advantages of using the TAM to obtain an autocatalytic model by curve fitting
are reported. With various autocatalytic models, such as the Prout-Tompkins equation and the Avrami-Erofeev rate law, the
best curve fit among models was also investigated and proposed. 相似文献
8.
Organic peroxides have been widely used in industries and are known to be self-reactive chemicals. In this paper, thermal
and infrared spectroscopic analyses were carried out to obtain a better understanding of the thermally hazardous behavior
of cumene hydroperoxide (CHP) with cumene solvent. The temperature and heat flow profiles of different concentrations of CHP
at scanning and isothermal conditions were measured with a small scale reaction calorimeter. Furthermore, probe type in situ infrared spectroscopic measurements were performed and the reaction mechanism will be discussed in regards to both energy
release and product identification. 相似文献
9.
Xiao-Lei Ni Jing Liu Ying-Ya Liu Karen Leus Hannes Depauw An-Jie Wang Pascal Van Der Voort Jian Zhang Yong-Kang Hu 《中国化学快报》2017,28(5):1057-1061
Two types of Mo containing metal-organic frameworks, denoted as Mo@COMOC-4 and PMA@MIL-101 (Cr), were synthesized respectively by a post-synthetic modification and a ship-in-bottle approach. The catalytic performance of both compounds in the epoxidation of propylene using cumene hydroperoxide (CHP) as oxidant was compared with MoO3@SiO2. A higher conversion (46.2%) and efficiency (87.4%) of CHP was observed for Mo@COMOC-4, whereas the heteropoly acids supported MIL-101 resulted in the decomposition of CHP due to its strong acidic character. Regenerability tests demonstrated that Mo@COMOC-4 could be reused for multiple runs without significant loss in both activity and stability. © 2017 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. 相似文献
10.
Guoyong Che Jing Xiang Tian Tian Qingfei Huang Linfeng Cun Jian Liao Qiwei Wang Jin Zhu Jingen Deng 《Tetrahedron: Asymmetry》2012,23(6-7):457-460
A chiral titanium complex, formed in situ from Ti(Oi-Pr)4, (S,S)-N,N′-dibenzyl tartramide and water was found to serve as an efficient catalyst for the asymmetric oxidations of 1H-benzimidazolyl pyridinylmethyl sulfides with cumene hydroperoxide (CHP) in the absence of a base. Several proton pump inhibitors (PPIs), such as esomeprazole, lansoprazole, rabeprazole and pantoprazole were obtained in high yield (up to 92%) and excellent enantiomeric excess (up to 96%). 相似文献
11.
12.
V. M. Zakoshansky 《Russian Journal of General Chemistry》2011,81(5):865-883
It is demonstrated that, in the course of the cumene oxidation reaction promoted by dissolved oxygen (O2liquid), newly-formed retarders-inhibitors (In) reduce the values of relationships between radicals and inhibitors, in particular
R·/In and ROO·/In, thus leading to a decrease in cumene hydroperoxide formation rate, in the degree of cumene conversion, and in process
selectivity. Clear evidence of the dominant role of dissolved oxygen in the increase in formation of retarders/inhibitors
is provided, and it is also proven that preremoval of retarders/inhibitors is effective in overcoming the hydroperoxide concentration
limit, and in noticeably increasing the degree of cumene conversion, without major losses in selectivity. 相似文献
13.
D(-)-酒石酸二乙酯(1)分别与2-氨甲基吡啶和4-氨甲基吡啶反应,合成了D(-)-二吡啶甲基酒石酸酰胺2和3.分别以1~3为手性配体与钛酸异丙酯配合,催化过氧化氢异丙苯(CHP)不对称氧化埃索美拉唑前体(Eso-I)合成埃索美拉唑.结果表明,由配体2或3构成的催化体系在埃索美拉唑合成上显示出较高的催化活性和对映选择性.例如,当以2为配体,甲苯为溶剂,在优化的条件下进行反应时,Eso-I的转化率达84.7%,埃索美拉唑的选择性达91.8%,对映体过量值达89.0%. 相似文献
14.
Sheng-Hung Wu I-Jyh Wen Shu-Hsiang Hsu Yet-Pole I 《Journal of Thermal Analysis and Calorimetry》2013,113(2):885-888
Oxygen (O2) or air is widely used to produce cumene hydroperoxide (CHP) in the cumene oxidation tower. The aim of this study was applied to analyze thermal hazard of two by-products including alpha-methylstyrene (AMS) and acetophenone (AP) in a CHP oxidation tower. Differential scanning calorimetry (DSC) and thermogravimetry (TG) were operated to evaluate thermal runaway reaction of CHP mixed with AMS and AP. Exothermic onset temperature (T 0), maximum temperature (T max), activation energy (E a), etc., that were employed to prevent and protect thermal runaway reaction and explosion in the manufacturing process and storage area. In view of proactive loss prevention, the inherently safer handling procedure and storage situation should be maintained in the chemical industries. The T 0 of 30 mass% CHP was determined to be 105 °C by DSC. Therefore, the T 0 of 30 mass% CHP mixed with AMS was determined to be 60–70 °C by DSC. The exothermic reaction of CHP/AP and CHP/AMS by DSC under N2 reaction gas is thermal decomposition of oxygen–oxygen bond (–O–O–) because of the anaerobic reaction. 相似文献
15.
Xue Feng Li Huan Xin Gao Guo Jie Jin Lin Ding Lu Chen Hong Yun Yang Xin He Qing Ling Chen 《中国化学快报》2007,18(5):591-594
Silylated Ti-grafted hexagonal mesoporous silica (HMS) catalyst was prepared by the chemical vapor deposition (CVD) using TiCl4 as titanium source and hexamethyldisilazane (HMDSZ) as silylating agent. The samples were characterized by XRD, N2- adsorption, FTIR, 29Si NMR, DR UV-vis, and evaluated by epoxidation of styrene, propylene, cyclohexene, and 1-hexene with cumene hydroperoxide (CHP) as oxidant, respectively. It is revealed that the catalyst possesses typical mesoporous structure, high hydrophobicity and highly dispersed tetracoordinated titanium sites and hence exhibits excellent performance in epoxidation of olefins. 相似文献
16.
Chloromethylated polystyrene‐supported macrocyclic Schiff base metal complexes (PS‐L‐M, M = Cu2+, Co2+, Ni2+, and Mn2+) were synthesized and characterized by the methods of IR, ICP, and small area X‐ray photoelectron spectroscopy (XPS). The oxidation of cumene by molecular oxygen in the absence of solvent with the synthesized complexes employed as catalyst was carried out. In comparison with their catalytic activities, PS‐L‐Cu is a more effective catalyst for the oxidation of cumene. The main products are 2‐phenyl‐2‐propanol (PP) and cumene hydroperoxide, which were measured by GC/MS. The influences of reaction temperature, the amount of catalyst, as well as the reaction time on the oxidation of cumene were investigated. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
17.
Beata Orlińska 《Tetrahedron letters》2010,51(31):4100-154
Catalytic systems consisting of N-hydroxyphthalimide in combination with copper(II), cobalt(II) and manganese(II) acetylacetonate, acetate or chloride were applied to the oxidation of cumene with oxygen. The use of these catalytic systems decreases cumyl hydroperoxide selectivity as a result of the decomposition reaction of hydroperoxide to 2-phenyl-2-propanol and acetophenone. It has been demonstrated that the use of N-hydroxyphthalimide in combination with copper salts at 60 °C results in high alcohol content whereas ketone is the major product at 90 °C. The results can be used to develop a method for alcohol or ketone synthesis from other isopropyl-aromatic hydrocarbons. 相似文献
18.
P. Beaunez G. Helary G. Sauvet 《Journal of polymer science. Part A, Polymer chemistry》1994,32(8):1459-1469
Kinetics of methyl methacrylate polymerization initiated by a redox system [cumene hydroperoxide (CHP)/copper saccharinate] were studied in bulk at 20°C in the presence of accelerators such as N,N-dimethyl-p-toluidine (DMPT) and o-benzoic sulphimide (saccharin). Assuming a steady-state concentration of propagating radicals, the polymerization rate depends on the square root of the initiation rate and the kinetic orders with respect to each compound in the initiation step may be deduced. Initiation is first-order in CHP, copper saccharinate, and saccharin and second-order in DMPT. A reaction scheme consistent with these orders is proposed. The main features are the following: (1) CHP reduces rapidly Cu(II) to Cu(I); (2) a small fraction of Cu(I) is complexed with DMPT; (3) the complexed ions (Cu+, DMPT2) are strong reductants with respect to CHP whereas uncomplexed Cu+ are almost inactive; (4) the decomposition of CHP is strongly catalyzed by saccharin (protonated CHP is 13000 times more reactive than free CHP). Thus both accelerators are necessary to get high polymerization rates. © 1994 John Wiley & Sons, Inc. 相似文献
19.
The reaction between tert-butyl hydroperoxide (TBH) and dioctyltinbis(isooctyl thioglycollate) (DOTG) in chlorobenzene was found to be first order in each reactant with an initial rapid stoichiometric stage followed by a slower catalytic peroxidolysis. The activation energy of the stoichiometric reaction was 73.1 kJ mol?1 K?1. Analysis of the products of the reaction between cumene hydroperoxide (CHP) and DOTG revealed competing radical and ionic processes. In an oxidizable substrate (cumene), the CHP/DOTG interaction led to the exclusion formation of alcohol by hydrogen abstraction from the substrate in the initial stages; in the later stages, catalytic ionic decomposition of CHP was the predominant reaction. 相似文献
20.
Sheng-Hung Wu Jun-Yen Wu Yung-Tin Wu Jin-Chuan Lee Yi-Hao Huang Chi-Min Shu 《Journal of Thermal Analysis and Calorimetry》2013,111(1):669-675
Plenty of thermal explosions and runaway reactions of cumene hydroperoxide (CHP) were described from 1981 to 2010 in Taiwan. Therefore, a thermal explosion accident of CHP in oxidation tower in 2010 in Taiwan was investigated because of piping breakage. In general, high concentration of CHP for thermal analysis using the calorimeter is dangerous. Therefore, a simulation method and a kinetic parameter were used to simulate thermal hazard of high concentrations of CHP only by the researcher. This study was applied to evaluate thermal hazard and to analyze storage parameters of 80 and 88 mass% CHP using three calorimeters for the oxidation tower, transportation, and 50-gallon drum. Differential scanning calorimetry (DSC) (a non-isothermal calorimeter), thermal activity monitor III (TAM III) (an isothermal calorimeter), and vent sizing package 2 (VSP2) (an adiabatic calorimeter) were employed to detect the exothermic behavior and runaway reaction model of 80 and 88 mass% CHP. Exothermic onset temperature (T 0), heat of decomposition (ΔH d), maximum temperature (T max), time to maximum rate under isothermal condition (TMRiso) (as an emergency response time), maximum pressure (P max), maximum of self-heating rate ((dT/dt)max), maximum of pressure rise rate ((dP/dt)max), half-life time (t 1/2), reaction order (n), activation energy (E a), frequency factor (A), etc., of 80 and 88 mass% CHP were applied to prevent thermal explosion and runaway reaction accident and to calculate the critical temperature (T c). Experimental results displayed that the n of 80 and 88 mass% CHP was determined to be 0.5 and the E a of 80 and 88 mass% CHP were evaluated to be 132 and 134 kJ mol?1, respectively. 相似文献