Preparation drying

Although water was used as a proton donor in this preparation, drying of the liquid ammonia and ether was carried out so that the lithium-ammonia solution would not be exposed to water during preparation and so that the amount of water added could be accurately controlled. 

Sample preparation Dried greater celandine was pulverized and briefly boiled in 0.05 mol sulfuric acid. After cooling to room temperature the mixture was placed in a separating funnel and adjusted to pH 10 with ammonia solution and extracted once with chloroform. The organic phase was dried with sodium sulfate and evaporated to dryness under reduced pressure. The residue was taken up in methanol and used as the sample solution for TLC. 

The reaction of magnesium and methanol to form magnesium methoxide and used to prepare dry methanol [1] is very vigorous, but often subject to a lengthy induction period. Sufficient methanol must be present to absorb the violent exotherm which sometimes occurs [2], Mixtures of powdered magnesium (or aluminium) and methanol are capable of detonation and are more powerful than military explosives [3],... 

Membrane Preparation. Dried cellulose diacetate is dissolved in acetone in the weight ratio of 1 to 3 or 4. Gaseous ammonia is directed at room temperature over the solution surface in a rotary evaporator, the ammonia being readily absorbed by the polymer solution. Optimal ammonia concentration is 5 to 6 wt-%, a typical casting solution composition is cellulose diacetate/acetone/ ammonia 18.8/75.2/6.0 (solvent-to-polymer ratio 4). Casting is at room temperature. The precipitation bath is maintained at pH 4 through controlled addition of hydrochloric acid to compensate for the alkaline intake. 

SAMPLE PREPARATION. Dry Illinois No. 6 (Herrin seam, -60 mesh) was used in the sorption studies. Analysis Found C, 74.37 H, 4.83 N, 1.76 S, 1.76 O (by difference), 8.74 Ash, 8.33 (duplicate). Approximately 10 g of the sample was exhaustively Soxhlet extracted with pyridine. Extractability was 18.7% (wt). The pyridine solution was then filtered through a 0.4 /xm filter to insure removal of particulates and colloidal material. The filter did not plug. Most of the pyridine was removed by rotovaporization under reduced pressure at 70-80 C. Approximately 200 mL of a methanol/water (80/20 vol) mixture and 2 mL of cone. HCl were added to the flask and the mixture was stirred under nitrogen for two days. The solid extract was then filtered and dried under vacuum at 105 "C for 24 hours. Analysis Found C, 80.0 H, 5.64 N, 1.85 S, 0.70 Ash, 0.30 (duplicate). 

The enzyme might have been partly inactivated during the catalyst preparation (drying, etc.). 

Water extract of W. sativa was prepared, dried and powdered. Powder was dissolved in phosphate buffer saline (pH 6.4) and centrifuged at 10.000 rpm for 30 min at 4 °C. The supernatant was collected as the soluble extract by removing the oily layer and unsoluble pellet. Protein concentration of the soluble extract was determined with Bradford method. Then proteins dialyzed against 0.05 M phosphate buffer (pH 6.4) using 3500 MW cut off dialyzing bags and centrifuged. 

Figure 54.2 Brazilian native preparing dry rubber by smoking latex coated wooden shovel over a pot of burning palm nuts. Turtle shell bowl contains small pool of latex. Source-. Engraving from The Amazon and Madeira Rivers by Franz Keller published by J. B. Lippincott and Company, Philadelphia, 1875. The Library of Congress.

Assemble an apparatus as shown in Fig. 71. Connect cooler 4 to a 100-ml round-bottomed flask with the aid of special adapter 1. Connect apparatuses for preparing dry chlorine (see Fig. 61) and... 

Comparison of Adsorptivity of Activated and Non-Activated Carbon. Assemble an apparatus for preparing dry chlorine (see... 

In preparing dry blends the peroxide was added to each component separately, and the resulting masterbatches were blended for 5 minutes on a roll mill at 70°C. All samples were press-cured for 30 minutes at 153 °C into films approximately 0.2 mm thick. 

Soluble salts can be made using a base and an acid, a Complete this method of preparing dry crystals of the soluble salt cobalt(n) chloride-6-water from the insoluble base cobalt(n) carbonate. 

Figure 6.11 Schematic model of oxidation of carbon monoxide on as-prepared (dried) An/Fe20 j proposed by Makkee et ai33 (Reprinted with permission from J. Catal. 230 (2005) 52.)...

When a single product is sought, the baking reaction is often employed (Fig. 13.60). In this process, the sulfate salt of aniline is prepared, dried, and then baked in an oven under vacuum. The product in this case is the important dye intermediate, sulfanilic acid. Similarly, naphthylamine sulfonic acid can be produced, and if the para-position is occupied, sulfonation of an ort/m-position occurs (Fig. 13.61). 

Pretreatment is extremely important in determining surface chemistry. Samples must be carefully prepared, dried, oxidized, reduced, and kept in the desired final state until admission of probe molecules and recording of spectra. Seemingly minor differences in preparation or pretreatment can produce major differences in the surface chemistry of many catalysts. Adsorbable impurities in conventional high vacuum systems do not usually seriously contaminate typical high-area catalyst samples. If, however, samples stand for many hours significant changes can often be observed, particularly with reduced supported metals. 

---