Urea method

Chapter III. 1 Heptene (111,10) alkyl iodides (KI H3PO4 method) (111,38) alkyl fluorides (KF-ethylene glycol method) (111,41) keten (nichrome wire method) (111,90) ion exchange resin catalyst method for esters (111,102) acetamide (urea method) (111,107) ethyl a bromopropionate (111,126) acetoacetatic ester condensation using sodium triphenylmethide (111,151). 

A modified DP method with urea as a precipitating agent, called the DP urea method, has been developed for Ti02 support [27]. Deposition of gold NPs by this method was appHed to AI2O3 [28], Ce02 [28], and Mn203 [29] supports. Aqueous urea solution produces hydroxyl ions above 60 °C as foUows ... 

Flytzani-Stephanopoulos and coworkers—urea method for preparing high surface area ceria/substituting noble metals with base metals/cationic active sites for Au and Pt-ceria catalysts/deactivation by hydroxycarbonates and improved stability with 02 co-feeding. Li et al.396 reported on low temperature water-gas shift catalysts in their search for a replacement catalyst for Cu/ZnO suitable for use in a fuel... 

Despite the described disadvantages, but due to the high yield, economical production methods, and low-cost starting materials, the phthalic anhydride/urea method is presently the most significant industrial route to Copper Phthalocyanine Blue manufacture. 

PMR studies have been performed on a number of other ribosomal proteins isolated by the acetic acid/urea method (Morrison etal., 1977a). The results of these studies have shown that acedc acid/urea-extracted proteins contain little tertiary structure. However, some structure was seen in protein S4 and especially in protein S16 as indicated by the appearance of ring-current shifted resonances in the apolar region of the spectrum (Morrison et al., 1977b). These are due to the interaction of apolar methyl groups with aromatic amino acids in the tertiary structure of the protein. The PMR spectra were recorded either in water or in dilute phosphate buffer at pH 7.0—conditions under which the proteins were soluble. 

Fig. 5 Scanning electron microscope images for LDHs synthesized by the urea method with a aging times 6, 30, 45, and 69 h, and b the concentration of metal ions, 0.87, 0.65, 0.44, and 0.06 M (scale bar = 2.5 jjim). Reprinted with permission from [76], Copyright...

This film formation was an undesirable side effect—for accurate analysis, the film needed to be removed and added to the precipitate. However, as pointed out by Gordon [1], To those who have worked with the urea method, the existence of these films will always be a reminder of Willard s fond hope that he will someday find a way of making all the precipitate adhere to the beaker so that it will only be necessary to dry and weigh the beaker after discarding the solution. ... 

S1SO4 ZnS04 anthracene adipic acid sugars citric acid phenols xylenes naphthalene paraffin urea methods and parameters of... 

Or plasmolyze by transferring to 400 ml distilled water at 2°C, homogenize and alkylate as in urea method... 

Clark, P.M.S., Kricka, L.J. and Whitehead, T.P. (1981). Matrix effects in clinical analysis Commutability of control materials between the Ektachem, Beckman and SMA 12/60 glucose and urea methods. Clin. Chim. Acta 113, 293-303. Ektachem Blood Urea Nitrogen Test Methodology, I9I-8-8I-A (1981). Ektachem Glucose Test Methodology, 190-8-81-A (1981). 

Comparatively pure linoleic acid can be obtained, for example, by the purification of safflower oil fatty acid such as low temperature recrystallization method, distillation method, urea method, salt recrystallization method, etc. Source Seki 1971... 

Catalyst A, another preparation by the urea method but less well washed in the gel stage. Rato of heating, 125°/hour. 

As indicated in Section IV, one might worry that the surface of chromia would become oxidized upon drying in air at 100-110° and that reduction by hydrogen of the oxidized form contributes in some special way to the formation of surface coordinatively unsaturated Cr3+. A chromia gel prepared by the urea method (21) which was dried at room... 

Kjeldahl and Blood Urea Methods. J. biol. Chem. 102, 489 (1933). 

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