Ampuls

Anhydrous, monomeric formaldehyde is not available commercially. The pure, dry gas is relatively stable at 80—100°C but slowly polymerizes at lower temperatures. Traces of polar impurities such as acids, alkahes, and water greatly accelerate the polymerization. When Hquid formaldehyde is warmed to room temperature in a sealed ampul, it polymerizes rapidly with evolution of heat (63 kj /mol or 15.05 kcal/mol). Uncatalyzed decomposition is very slow below 300°C extrapolation of kinetic data (32) to 400°C indicates that the rate of decomposition is ca 0.44%/min at 101 kPa (1 atm). The main products ate CO and H2. Metals such as platinum (33), copper (34), and chromia and alumina (35) also catalyze the formation of methanol, methyl formate, formic acid, carbon dioxide, and methane. Trace levels of formaldehyde found in urban atmospheres are readily photo-oxidized to carbon dioxide the half-life ranges from 35—50 minutes (36). 

The bulk polycondensation of (10) is normally carried out in evacuated, sealed vessels such as glass ampules or stainless steel Parr reactors, at temperatures between 160 and 220°C for 2—12 d (67). Two monomers with different substituents on each can be cocondensed to yield random copolymers. The by-product sdyl ether is readily removed under reduced pressure, and the polymer purified by precipitation from appropriate solvents. Catalysis of the polycondensation of (10) by phenoxide ion in particular, as well as by other species, has been reported to bring about complete polymerisation in 24—48 h at 150°C (68). Catalysis of the polycondensation of phosphoranimines that are similar to (10), but which yield P—O-substituted polymers (1), has also been described and appears promising for the synthesis of (1) with controlled stmctures (69,70). 

Commercially available containers for use with parenteral products include single-dose ampuls that are heat sealed and opened by snapping at the point of least diameter, vials for multidose use, and botdes and pHable bags that are used for large volumes such as needed in intravenous infusions. Container size can vary from 1 mL to 1 L. Generally volumes up to 100 mL are available as ampuls or vials. 

Total U.S. production of potassium metal is less than 500 t/yr. There are few commercial producers worldwide, although some companies produce potassium captively. The more prominent producers are CaHery Chemical Company (a division of Mine Safety AppHances Company) in the United States and the People s RepubHc of China. Potassium may be manufactured in Russia as well. Strem Chemicals (U.S.) suppHes small quantities in ampuls. 

Smaller quantities of potassium and NaK are available in glass or metal ampuls (<100 g), or in stainless cylinders containing 12—13 kg. Potassium is also available in 84- or 209-L dmms (containing 75 and 135 kg, respectively). NaK is available in cylinders containing 91 or 340 kg. 

Statistical control of an analysis or instmment is best demonstrated by SQC of a standard sample analysis. The preferred approach to demonstrate statistical control is to use a reference sample of the subject material that has been carefully analyzed or, alternatively, to use a purchased reference standard. Either material must be stored so that it remains unchanged, eg, sealed in ampuls or septum capped bottles. Periodically a sample can then be reanalyzed by the technique used for routine analysis. These results are plotted in a control chart. Any change in the stabihty of the test in question results in a lack of... 

For shipping purposes, the ampul is placed in aluminum foil or polyethylene bags. The wrapped ampul is packed in a metal can and surrounded by an inert filler material such as vermiculite. These precautions are necessary in order to minimize the chances of ampul breakage during shipment. Most mbidium compounds, however, can be shipped as nonhazardous materials. These compounds are usually stored in glass or polyethylene botdes. 

The supply and demand for mbidium compounds has grown steadily since the 1970s. In 1979 the U.S. demand was ca 1040 kg of contained mbidium (16), and total world demand was estimated at approximately twice that of the United States. Reserves of mbidium in North America are estimated at 2 X 10 kg the United States is - 100% import-reliant for mbidium, and Canada is the principal source of the raw material (16). The demand for mbidium metal is small compared to the demand for mbidium compounds. Table 2 fists approximate prices of mbidium metal and mbidium compounds. Primary producers of mbidium are Cabot Performance Chemicals (Boyerstown, Pennsylvania), MSA Research Corporation (Callery, Pennsylvania), and CM Chemical Products, Inc. (Berkeley Heights, New Jersey). Research quantities of mbidium in standard and specialized ampuls are available from Strem Chemicals, Inc. (Newburyport, Massachusetts). 

Chemical indicators for dry-heat steriliza tion are available either in the form of pellets enclosed in glass ampuls, or in the form of paper strips containing a heat-sensitive ink. The former displays its end point by melting, the latter by a color change (see Chromogenic materials). 

There is no fiiU-scale U.S. commercial production of thiophosgene, but it is available in glass ampuls from laboratory reagent suppHers. Thiophosgene may be produced in Israel as an intermediate for tolnaftate (2-naphthyl A/-methyl-A/-y -tolylthiocarbamate) [2398-96-17, an antifimgal dmg. 

If many zones are present in the sample simultaneously, it may be advantageous to move the ampul (or heaters) slowly by one zone spacing, and then rapidly backward to catch the next zone. By such a reciprocating action, many zones can be moved continuously through the sample without a bank of heaters longer than the sample. 

Heat is often removed by simply allowing it to escape by convection, radiation, and conduction. However, such uncontrolled escape can lead to very large temperature fluctuations. It is better to surround the entire container, heaters and all, with a controUed-temperature cooled chamber. Even then, buoyancy-driven free convection from the ampul can lead to small temperature fluctuations. Jets of air or cooling water appHed directly onto the ampul adjacent to the heater have been employed. Both temperature and flow rate of the coolant should be controlled. 

At temperatures above 150°C, dehydration continues to yield viscous Hquid phases beyond the metaboric acid composition (39). The most stable form of metaboric acid, cubic HBO2-I or y-form (d = 2.49 g/mL, mp = 236° C) crystaUi2es slowly when mixtures of boric acid and HBO2-III are melted ia an evacuated, sealed ampul and held at 180°C for several weeks (41). 

To assay liquid biomine, an ampule of biomine is cmshed under tfie surface of an aqueous potassium iodide solution and the resultant iodine titrated with standard sodium thiosulfate. 

The samples were collected and processed in a manner to avoid exposure to oxygen and control loss of moisture then they were pulverized to convenient sizes for research, ie, <149 fim ( — 100 mesh) and <840 fim (—20 mesh) the entire ton was thoroughly mixed and packaged in sealed glass ampules under nitrogen. These samples have been well characterized and are available in quantities that are expected to last for decades (Table 8). 

Batch Reactors In the simplest land of investigation, reactants can be loaded into a number of ampules, kept in a thermostatic bath for various periods, and analyzed. 

Veiy small containers, such as ampules, and containers holding liquids for use other than storage, such as batteries, which may be disposed directly in a hazardous-waste landfill. 

Anisaldebyde (p-metboxybenzaldebyde) [123-11-5] M 136.2, m -1", b 249"/atm, 89-90"/2mni, d 1.119, n 1.576. Washed with saturated aq NaHC03, then H2O, steam distd, extracted distillate with Et20, dried (MgS04) and distd under vac and N2. Store in glass ampules under N2 in the dark. 

Pelargonyl chloride (nonanoyl chloride) [764-85-2] M 176.7, b 88 /12mm, d 0.941, n 1.436. Refluxed with acetyl chloride ( 3 vols) for Ih, then distil off the AcCl followed by the nanoyl chloride under reduced pressure. It is moisture sensitive and should be stored in sealed ampules. 

Soianone [5( + )-/rn s-2-methyi-5-isopropyi-l,3-nonan-8-one] [1937-54-8] M 194.3, b 60< /lmni, [alp +14" (neat). Purified by high vacuum distillation and stored in sealed ampules [Kohda and Sato J Chem Soc, Chem Commun 951 7957]. It has UV (hexane) at Xmax 230nm (e 11,800). 

Titanium tetrabromide [7789-68-6] M 367.5, m 28.3°, b 233.5 , d 3.3. Purified by distn. Distillate forms light orange hygroscopic crystals. Store in the dark under N2 preferably in sealed brown glass ampules. [Olsen and Ryan J Am Chem Soc 54 2215 1932.]... 

The only known representative of this type of compound, 91, was prepared by 1,3-dipolar addition of mesityl nitrile oxide to telluroketone 85 (93JA7019 94MI1). The reaction proceeds smoothly on heating equimolar amounts of the reactants at 80°C, giving rise to 91 in 70% yield. The heterocycle is a thermally unstable and light-sensitive compound. Thermolysis of a deuterochloroform solution of 91 at 60-90°C in a sealed ampule affords 1,1,3,3-tetramethylindanone and mesityl isonitrile (94MI1). 

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