Au preparation

Fig. 2. CO conversions at 363 K in the dry condition (open points) and 353 K in the wet condition (filled points) over lOOmg and 50 mg of Aa/CeOi catal) containing 0.95 wt% Au prepared at different calcination temperatures (373 K (circle), 473 K(square), 573 K(triangle up), 673 K (triangle down), 773 K (diamond), 873 K (hexagon)). The reactants of 100 ml/min, 1 vol% CO and 1 vol% O2 in He, were fed to the catalyst.

This part of the CQP concept consists of aU preparations necessary before the actual CQP monitoring systems can be developed. It includes ... 

Figure 1. TEM image of a titania supported gold catalyst (1.7wt.% Au) prepared by deposition-precipitation (gold particle size = 5.3+ 0.3 nm, dispersion = 36%). (Reprinted from Reference [84], 2000, with permission from American Chemical Society).

The related complexes [Os3(CO)nX(AuPR3)] are thought to have structure (123),762,763,765,766 while the remarkable compound [ Os3( -H) (CO) 10 2( 4-Au)]-, prepared as the [N(PPh3)2]+ salt by reaction of (122 X = H) with [N(PPh3)2]Cl, has structure (124). This complex has square planar gold(I) bridging between the two Os3 clusters.767 The interaction between gold... 

Finely divided metal samples can also be prepared in the form of evaporated films in high vacuum, usually deposited on IR-transparent alkali halide plates (76-78). Such spectra are of interest in themselves, but tend to be much weaker than those obtained from the metal-particles-in-depth, oxide-supported catalysts. The rough surfaces of films of Cu, Ag, and Au, prepared by deposition on cold surfaces, can lead to very high-quality surface-enhanced Raman spectra (27, 28, 79, 80). The results from such experiments will be discussed in the later sections devoted to particular adsorbed hydrocarbons and metals, alongside the majority of spectra that are obtained on oxide-supported samples. 

S-23 Hie folfowisig molecule won formed by an intraroorecular aided naacnon. dior-bonyt krecunor used far aU preparation ... 

Selenium analogues of many P-S compounds have been prepared, the number of well-characterised P-Se compounds remains comparatively small. Owing to the high toxicity of selenium, special precautions are needed in aU preparative work. Many P-Se compounds are the structural analogues of the corresponding P-S compounds while others illustrate a somewhat greater capacity of Se to form long chains. 

Recently, we have compared probe-doped RSCE aerogels, CSCE aerogels and xerogels, aU prepared from the same precursor mixmres [17]. The oxygen-sensitive probes PtOEP and platinum (II) mesotetrafluoro phenylporphyrin (PtTFPP) were included in the TMOS precursor mixture, and then aliquots of the mixmre were processed in three different ways. 

Although the initial products at ICI were mainly made from unsubstituted phthaUmide, the majority of their compounds were aU prepared by the condensation of a primary diamine with the corresponding 3-iminoisoindolinone derivative 3, affording in general yellow or orange pigments. 

Silver. Tetrameric [2-Ag-(Me2NCHa)-ferrocene] is isostructural with the copper cluster. The i.r. spectra of NCCRgCHaC CM (M = Ag or Au) prepared from the terminal acetylene and a M+ salt in NH3, indicated d -p interaction between M and the C=C bond. The synthesis of cyclic [Me2P(CH2)2Ag]a has been reported. ... 

Figure 2 Mdssbauer spectra of the source of Fe Au, prepared by diffusing Co into a foii of Au the totai impurity content (Co + Fe) was beiow 10 ppm. The source was attached to the mixing chamber of a He/ He cryostat. The absorber was iron potassium hexaoyanide at 1.3 K in the same externai fieid (/ixt 6.0 T). The solid lines are fits to the spectra including line broadening due to relaxation effects or a distribution of hyperfine field.

The slightly modified synthesis route (Stojanovic et al., 2010) could also be apjplied for the preparation of both ammonium- and phosphonium-based ILs containing functionalized anions like thiosalicylate, 2-(methylthio)benzoate, or phenyl(thio)acetate. AU prepared ILs exhibited chloride contents below 0.9 wt.%. However, due to the significantly high viscosities of the obtained ILs (up to 5242 mPas), the use of appropriate organic solvents was... 

Au°, while aurothiomalate suppressed only the development of mycobacterial adjuvant. The Au° preparation was approximately 1000 times more potent than aurothiomalate (per gold content). 

Uosaki K, Shen Y and Kondo T 1995 Preparation of a highiy ordered Au(111) phase on a poiycrystaiiine goid substrate by vacuum deposition and its characterization by XRD, GiSXRD, STM/AFM and eiectrochemicai measurements J.Phys. Chem. 99 14 117-14 122... 

By dropping au aromatic acid either alone or mixed with an aliphatic acid into a tube containing a thoria catalyst deposited on pumice and heated to 400-450°. This method is generally employed for the preparation of mixed aromatic - aliphatic ketones. Excess of the aUphatic acid is usually present since this leads to by-products which are easily separated and also tends to increase the yield of the desired ketone at the expense of the symmetrical ketone of the aromatic acid. Thus —... 

The preparation of a series of transition metal complexes (Co. Ni. Pd. Pt, Ir. Au. Cu. Ag) with ambident anion (70) and phosphines as ligands has been reported recently (885). According to the infrared and NMR spectra the thiazoline-2-thione anion is bounded through the exocyclic sulfur atom to the metal. The copper and silver complexes have been found to be dimeric. 

Determination of gold concentrations to ca 1 ppm in solution via atomic absorption spectrophotometry (62) has become an increasingly popular technique because it is available in most modem analytical laboratories and because it obviates extensive sample preparation. A more sensitive method for gold analysis is neutron activation, which permits accurate determination to levels < 1 ppb (63). The sensitivity arises from the high neutron-capture cross section (9.9 x 10 = 99 barns) of the only natural isotope, Au. The resulting isotope, Au, decays by P and y emission with a half-life of 2.7 d. 

Cyanides. Salts of the complex ion, [Au(CN)2] , can be formed directiy from gold, ie, gold dissolves ia dilute solutions of potassium cyanide ia the presence of air. Additionally, a gold anode dissolves ia a solution of potassium cyanide. The potassium salt can be isolated by evaporation of the solution and purified by recrystallization from water (177). Boiling of the complex cyanide ia hydrochloric acid results ia formation of AuCN [506-65-01]. Halogens add oxidatively to [Au(CN)2] to yield salts of [Au(CN)2X2] which are converted to the tetracyanoaurates usiag excess cyanide (178). These last can also be prepared directiy from the tetrahaloaurates. 

Olefin and acetylene complexes of Au(I) can be prepared by direct iateraction of the unsaturated compounds with a Au(I) hahde (190,191). The resulting products, however, are not very stable and decompose at low temperatures. Reaction with Au(III) hahdes leads to halogenation of the unsaturated compound and formation of Au(I) complexes or polynuclear complexes with gold ia mixed oxidatioa states. 

Wet spinning of this type of hoUow fiber is a weU-developed technology, especiaUy in the preparation of dialysis membranes for use in artificial kidneys. Systems that spin more than 100 fibers simultaneously on an around-the-clock basis are in operation. Wet-spun fibers are also used widely in ultrafiltration appUcations, in which the feed solution is forced down the bore of the fiber. Nitto, Asahi, Microgon, and Romicon aU produce this type of fiber, generaUy with diameters of 1—3 mm. 

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