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181.
Iraj Mohammadpoor-Baltork Majid Moghadam Shahram Tangestaninejad Valiollah Mirkhani Ahmad Reza Khosropour Arsalan Mirjafari 《Monatshefte für Chemie / Chemical Monthly》2010,14(1):1083-1088
Abstract
1-Methylimidazolium hydrogensulfate, [Hmim][HSO4], a Br?nsted acidic room temperature ionic liquid, is used as a catalyst and reaction medium for facile and eco-friendly deprotection of methoxymethyl (MOM) and ethoxymethyl (EOM) ethers to their corresponding alcohols under thermal conditions (Δ) and microwave irradiation (MW). Furthermore, one-pot interconversion to the respective acetates and trimethylsilyl (TMS) ethers was also achieved. 相似文献182.
Iraj Mohammadpoor-Baltork Majid Moghadam Shahram Tangestaninejad Valiolah Mirkhani Arsalan Mirjafari 《Comptes Rendus Chimie》2010,13(12):1468-1473
In the present work, the catalytic activity of 12-tungstophosphoric acid immobilized on [bmim][FeCl4] ionic liquid as a highly efficient and eco-friendly catalytic system for rapid and chemoselective direct conversion of MOM- or EOM-ethers into their corresponding nitriles, bromides and iodides under microwave irradiation is reported. In these reactions, the products are obtained in high yields. The catalyst exhibited remarkable reactivity and was reused several times. 相似文献
183.
Minoo Dabiri Peyman Salehi Mahboobeh Bahramnejad Mohsen Alizadeh 《Monatshefte für Chemie / Chemical Monthly》2010,46(6):877-881
Abstract
An effective one-pot three-component route to 4(3H)-quinazolinones from commercially available starting materials is reported. Thus, isatoic anhydride reacted with ammonium acetate or primary amines and aldehydes in the presence of iodine to produce the corresponding quinazolinone derivatives in moderate to good yields. 相似文献184.
Zahra Khubi-Arani Mehdi Salami-Kalajahi Mohammad Najafi Hossein Roghani-Mamaqani Vahid Haddadi-Asl Seyed Mehdi Ghafelebashi-Zarand 《Polymer Science Series B》2010,52(3-4):184-192
In the present study, based on a complete mechanism, a Monte Carlo simulation method is employed to investigate the kinetics of styrene free radical polymerization over bi-functional initiators in a bulk medium. The effects of the concentration of initiator and the monomer, of the temperature on monomer conversion, average molecular weights, polydispersity index, and molecular weight distribution are inspected and compared with mono-functional initiators. According to the simulation results, an increase in either the concentration of initiator or the temperature leads to the rise of the monomer conversion and to the reduction of the average molecular weights, while the increase of the monomer concentration results in the rise of both monomer conversion and molecular weights, which is in accord with predictions of the theory of free-radical polymerization. In addition, application of bi-functional initiators increases both monomer conversion and average molecular weight and results in narrower chain length distributions. 相似文献
185.
Majid Moghadam Shahram Tangestaninejad Valiollah Mirkhani Iraj Mohammadpoor‐Baltork Naghmeh Sadat Mirbagheri 《应用有机金属化学》2010,24(10):708-713
In the present work, highly efficient epoxidation of alkenes catalyzed by Mo(CO)6 supported on multi‐wall carbon nanotubes modified by 2‐aminopyrazine, APyz‐MWCNTs, is reported. The prepared catalyst was characterized by elemental analysis, scanning electron microscopy, FT IR and diffuses reflectance UV–vis spectroscopic methods. This new heterogenized catalysts, [Mo(CO)6@APyz‐MWCNT], was used as a highly efficient catalyst for epoxidation of alkenes with tert‐BuOOH. This robust catalyst was reused several times without loss of its catalytic activity. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
186.
Mohammad Hossein Mirjalili Peyman Salehi Ali Sonboli Masood Mohammadi Vala 《Chemistry of Natural Compounds》2006,42(1):19-23
In this paper the variation in the quantity and quality of the essential oil of Salvia officinalis during its life cycle stages is reported. The oils were obtained by hydrodistillation of air-dried samples. The yield of
essential oil (w/w %) in different stages was in the order: floral budding (0.9%) > vegetative (0.7%) > flowering (0.5%) >
immature fruit (0.4%) > ripen fruit (0.2%). The essential oils were analyzed by GC and GC-MS. In total, 36, 41, 40, 38, and
41 constituents were identified and quantified in the subsequent stages, respectively. Oxygenated monoterpenes were the main
group of compounds in the fruiting set (56.9%), vegetative (48.5%), flowering (47.7%), and floral budding (45.3%) stage. 1,8-cineole
as one of the major constituents of all samples was lower in the vegetative stage and gradually increased in subsequent harvesting
times to reach a maximum in flowering and then decreased in the fruiting set. In contrast, the globulol content was higher
in the first stage and decreased drastically during fruit maturation.
Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 16–19, January–February, 2006. 相似文献
187.
Minoo Dabiri Peyman Salehi Mostafa Baghbanzadeh Ali A. Mohammadi 《Tetrahedron letters》2005,46(36):6123-6126
KAl(SO4)2·12H2O was found to catalyze efficiently a one-pot three-component cyclocondensation of isatoic anhydride and primary amines or ammonia sources such as (NH4)2CO3, NH4OAc and NH4Cl with aromatic aldehydes under mild conditions to afford the corresponding mono- and disubstituted 2,3-dihydroquinazolin-4(1H)-ones in good yields. 相似文献
188.
Monitoring of the pesticide diazinon in soil, stem and surface water of rice fields. 总被引:1,自引:0,他引:1
Alireza Ghassempour Ali Mohammadkhah Fazel Najafi Mohammad Rajabzadeh 《Analytical sciences》2002,18(7):779-783
Diazinon is an organophosphorus insecticide (OPP) that is used as a pesticide for Chilo suppressalis (WLK) (Lep., Pyralidae) in rice fields. The extraction of diazinon from soil and the stems of rice plants has been carried out by microwave-assisted extraction (MAE) and the results compared with ultrasonic extraction (USE). The best parameters for MAE are hexane-acetone (8:2 v/v) as a solvent, a 2.5 min extraction time, and 20 ml of the solvent volume. Also, surface-water samples of the rice fields were extracted by solid phase extraction (SPE) using a C18 disc. The optimum conditions of SPE were a sample volume of 750 ml, a pH of 7 and high ionic strength of water. The extracted samples were analyzed by gas chromatography-mass spectrometry (GC-MS). The relative standard deviation (RSD) and regression coefficients related to the linearity were <3.5% (n = 5) and 0.99, respectively. The limit of detection (LOD) is 0.1 ng ml(-1) with selected ion monitoring (SIM) at 137 m/z. The average recoveries of diazinon in soil and stem samples by MAE and surface-water by SPE were 98% (+/-3), 94% (+/-5) and 87% (+/-3), respectively. In June, the concentration of diazinon in soil and stem samples of the rice plants in Guilan province is high (55 ng ml(-1)) and in September is low (2 ng ml(-1)). In surface-water samples, the results are converse. In November, diazinon can not be detected in soil, stem or surface-water samples. Diazinon is degraded to diethylthiophosphoric acid. Also, three microorganism genera (Pseudomonas sp, Flavobacterium sp and Agrobacterium sp) have been found to degrade diazinon in soil and surface water. 相似文献
189.
Alireza Ghassempour Nahid Mashkouri Najafi Ali Asghar Amiri 《Journal of Analytical and Applied Pyrolysis》2003,70(2):3103-261
Rapid and sensitive determination of citric acid in fermentation media by pyrolysis mass spectrometry (Py–MS) is proposed. Owing to high specificity of this method, distinguishing the citric acid from the matrix and by-products formed in the Krebs cycle is possible. Selected ion monitoring (SIM) mode is used for quantitative measurements, in which mass to charge (m/z) values of 175 of citric acid and 138 of 3-nitroaniline as internal standard are chosen. Limit of detection (LOD) for this method has been found to be 1 ng ml−1 and the linear working range was 10 ng ml−1–100 mg ml−1. Relative standard deviation (R.S.D.) of the method for five replicates was 0.84%. Results of Py–MS are compared with those obtained by UV–vis spectrophotometric method. Also, factor analysis is used for evaluating the influence of pH, molasses concentration, time and shaker intensity on the production of citric acid by Aspergillus niger. 相似文献
190.
Valiollah Mirkhani Shahram Tangestaninejad Majid Moghadam Bahram Yadollahi Ladan Alipanah 《Monatshefte für Chemie / Chemical Monthly》2004,135(10):1257-1263
Summary. Efficient esterification of primary and sterically-hindered secondary or tertiary alcohols with acetic anhydride was achieved in the presence of ammonium decatungestocerate(IV) icosahydrate, (NH4)8[CeW10O36]·20H2O, as catalyst in high yields. Primary and secondary alcohols were also converted to their corresponding acetates and formates with acetic acid and ethyl formate in the presence of this catalyst. Easy work-up, non-toxicity, reusability, and stability of the catalyst are noteworthy advantages of this method. 相似文献