نتایج جستجو برای: silica gel

تعداد نتایج: 136948  

Dadkhoda Chazanfari Mohammad M. Hashemi

Para-Aminobenzoic acid is supported on silica gel via reaction of activated silica gel and p-aminobenzoic acid which is then converted to its manganese and cobalt salts. A mixture of the manganese and cobalt salts of the acid is used to catalyze allylic and benzylic alcohols to their corresponding carbonyl compounds in reasonable yields using oxygen or air. Reactions are clean and the catal...

2002
Gautam Gundiah

Several methods have been employed to synthesize SiC nanowires. The methods include heating silica gel or fumed silica with activated carbon in a reducing atmosphere, the carbon particles being produced in situ in one of the methods. The simplest method to obtain b-SiC nanowires involves heating silica gel with activated carbon at 1360 uC in H2 or NH3. The same reaction, if carried out in the p...

Journal: :Journal of lipid research 1972
M D Ullman N S Radin

The 2-hydroxy fatty acids tend to yield streaks in thin-layer chromatography on silica gel plates. If potassium oxalate is included with binder-free silica gel, good spots are obtained. Similar difficulties are found in paper chromatography of the fatty acid derivatives of coenzyme A, especially with long-chain acids. The same thin-layer system gives good spots with these compounds.

Journal: :Zeitschrift fur Naturforschung. C, Journal of biosciences 1996
H J Woerdenbag L R Lutke R Bos J F Stevens R Hulst W H Kruizinga Y P Zhu E T Elema H Hendriks W van Uden N Pras

From aerial parts of the fern Pteris multifida Poir. (Polypodiaceae) two diterpenes, entkaurane-2 beta, 16 alpha-diol and ent-kaur-16-ene-2 beta, 15 alpha-diol, were isolated by repeated column chromatography using silica gel and silica gel impregnated with silver nitrate. The structures were confirmed by spectroscopic methods. Both compounds showed a moderate cytotoxicity to Ehrlich ascites tu...

Journal: :The Journal of antibiotics 1988
R Grote A Zeeck H Drautz H Zähner

By chemical screening methods we detected in the mycelium of Streptomyces griseoflavus (strain Tii 2880) the colabomycin-complex2) and a second compound, called 2880-ll (Rf values see Table 1). 2880-ll absorbed UV light on Silica gel F254, and turned black with molybdatophosphoric acid and dark brown with vanillinsulfuric acid. It could be separated from the crude extracts by silica gel chromat...

Journal: :The Journal of antibiotics 1999
I Momose H Iinuma N Kinoshita Y Momose S Kunimoto M Hamada T Takeuchi

New antibiotics designated decatromicins A and B were isolated from the culture broth of Actinomadura sp. MK73-NF4. They were purified by butyl acetate extraction, silica gel column chromatography, silica gel TLC and Sephadex LH-20 column chromatography. Decatromicins A and B inhibited growth of Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA).

Journal: :Organic letters 2009
Ragnar S Stoll Stefan Hecht

The synthesis of a photoswitchable piperidine base, carrying a monochlorosilane anchoring group, and its immobilization on silica gel, mimicking an oxide surface, is reported. Efficient photoswitching between the E and Z isomers of the azobenzene photochrome was demonstrated for the immobilization precursor in solution and the immobilized piperidine base in suspension of the functionalized sili...

Journal: :Organic & biomolecular chemistry 2009
Roberta Bernini Sandro Cacchi Giancarlo Fabrizi Giovanni Forte Francesco Petrucci Alessandro Prastaro Sandra Niembro Alexandr Shafir Adelina Vallribera

The utilization of perfluoro-tagged palladium nanoparticles immobilized on fluorous silica gel through fluorous-fluorous interactions (Pd(np)-/FSG) or linked to silica gel by covalent bonds (Pd(np)-) in the alkynylation of terminal alkynes with aryl halides under aerobic, copper- and phosphine-free conditions in water, and their recovery and re-utilization, is described.

Journal: :تحقیقات مهندسی کشاورزی 0
نیره کریمی فارغ التحصیل کارشناسی ارشد دانشگاه منابع طبیعی و علوم کشاورزی گرگان لاله مشرف استادیار بخش تحقیقات فنی و مهندسی مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان اصفهان سعید ملک عضو هیأت علمی بخش تحقیقات فنی و مهندسی مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان اصفهان

the present study examined the effect of packaging film on the quantitative and qualitative properties of button mushrooms. the three types of packaging tested were a clear polyvinyl chloride box, polyvinyl chloride stretch film and biaxially-oriented polypropylene film (bopp). the five types of moisture absorbers examined were silica gel (2.5 g, 1.25 g), sodium chloride (2.5 g, 1.25 g), and si...

2014
Wade F. Zeno Silvia Hilt Kannan K. Aravagiri Subhash H. Risbud John C. Voss Atul N. Parikh Marjorie L. Longo

The entrapment of nanolipoprotein particles (NLPs) and liposomes in transparent, nanoporous silica gel derived from the precursor tetramethylorthosilicate was investigated. NLPs are discoidal patches of lipid bilayer that are belted by amphiphilic scaffold proteins and have an average thickness of 5 nm. The NLPs in this work had a diameter of roughly 15 nm and utilized membrane scaffold protein...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید