Drying vacuum oven

Triphenylmethylphosphonium bromide A pressure bottle is charged with a solution of 55 g (0.21 mole) of triphenylphosphine in 45 ml of dry benzene and cooled in an ice-salt bath. A commercially available ampoule of methyl bromide is cooled below 0° (ice-salt bath), opened, and 28 g (0.29 mole, approx. 16.2 ml) is added to the bottle in one portion. The pressure bottle is tightly stoppered, brought to room temperature, and allowed to stand for 2 days. After this time, the bottle is opened and the product is collected by suction filtration, the transfer being effected with hot benzene as needed. The yield of triphenylphosphonium bromide is about 74 g (99%), mp 232-233°. This material should be thoroughly dried (vacuum oven at 100°) before use in preparing the ylide. 

The acrylamide (AA) solutions as monomer of 20-40%, saturated N,N -methylenebisacrylamide (BIS) of 0.005-0.02% as cross-linker and 10% ammonium peroxodisulfate were added as initiator. The hydrogels were produced in small beads using micropipettes and kept in oven at 80°C to polymerize for four hours. Produced beads were washed with distilled water for removal of urmeacted monomers and dried vacuum oven and stored for later evaluations. 

Frequently the water or other solvent is so firmly held that it cannot be completely removed in a vacuum desiccator at the ordinary temperature. These substances are dried in a vacuum oven at a higher temperature. A convenient laboratory form of vacuum oven is the so-called... 

Ether - Starting fluid (works great - Quaaaaack ) 2. Home made mercuric acetate (Now this stuff can be special ordered from ones chem supplier but there s a delay, may look funny - Quaaaaack , and is more expensive. So what is the solution to this Make it yourself Its easy, quantitative, and cheaper. Strike mentions this in the book and points ducks to a reference. Follow the EXACT same procedure for Mercuric Propionate except use glacial acetic acid...quack ). You ll need to use 20 to 25% more of the home brew mercuric acetate since it is a little contaminated with acetic (ducks can t get it totally dry without a vacuum oven). 3. NaOH washed Brazillian is fine Quack No need to purify further for starting material ... 

Pigment used for dry blending is dried overnight at 150°C in a vacuum oven to remove absorbed gases and moisture. It is screened through a 149-p.m (100-mesh) screen directly onto the cubes, which are roUed or tumbled for at least 15 min. The pigmented resin is stored in an airtight container to prevent absorption of moisture. 

Moisture. Moisture is usually determined by a vacuum oven-dry method at 80°C. Moisture levels of more than 0.05% are likely to lead to caking or lumping problems which can make storage and transfer of bulk sugar difficult. The usual standard is 0.03%, which manufacturers can easily meet. Care must be taken to avoid temperature differentials ia storage which cause moisture to migra te and estabUsh pockets of unacceptably high moisture levels. 

Selected physical properties of sodium thiosulfate pentahydrate are shown in Table 1. The crystals are relatively stable, efflorescing in warm, dry air and dehquescing slightly in moist air. They melt in their water of hydration at 48°C and can be completely dehydrated in a vacuum oven at this temperature, or at atmospheric pressure at 105°C. Anhydrous sodium thiosulfate can also be crystallised direcdy from a 72% solution above 75°C. It decomposes at 233°C ... 

A good vacuum oven would serve for drying just as well, but the temperature of the salt should not exceed 110. ... 

Amino-2-methyl-l,3-propanediol [115-69-5] M 105.1, m 111 , b 151-152 /10mm, pK 8.80. Crystd three times from MeOH, dried in a stream of dry N2 at room temp, then in a vacuum oven at 55 . Stored over CaCl2 [Hetzer and Bates J Phys Chem 66 308 1962],... 

Azelaic acid [123-99-9] M 188.2, m 105-106". Crystd from H2O (charcoal) or thiophene-free benzene. The material cryst from H2O was dried by azeotropic distn in toluene, the residual toluene soln was cooled and filtered, the ppte being dried in a vacuum oven. Also purified by zone refining or by sublimation onto a cold finger at 10" torr. 

Benzotriazole [95-14-7] M 119.1, m 96-97 , 98.5 , 100 , b 159 /0.2mm, 204 /15mm, pKj 1.6, pK 8.64. Crystd from toluene, CHCI3, Me2NCHO or satd aq soln, and dried at room temperature or in a vacuum oven at 65 . Losses are less if material is distd in a vacuum. CAUTION may EXPLODE during vac distn, necessary precautions must be taken. [Org Synth Coll Vol III 106 1955.]... 

Biquinolin-4,4 -dicarboxylic (2,2 -bicinchoninic) acid [1245-13-2] M 344.3, m 367 , pKEst(i) 1.5, pl st(2) 4.0. Dissolve in dilute NaOH and ppte with acetic acid, filter, wash well with H2O and dry at 100° in a vacuum oven. Attempts to form a picrate failed. The methyl ester (SOCl2-MeOH) has m 165.6-166°. [J Am Chem Soc 64 1897 1942 68 2705 1946.] Fordi-K salt see entry in Chapter 5. 

Diaminoacridine sulfate (proflavin sulfate) [1811-28-5] M 516.6, m >300°(dec), Xmax 456nm. An aqueous soln, after treatment with charcoal, was concentrated, chilled overnight, filtered and the ppte was rinsed with a little diethyl ether. The ppte was dried in air, then overnight in a vacuum oven at 70°. 

Didodecyldimetbylammonium bromide [3282-73-3] M 463.6, m 157-162 . Recrystd from acetone, acetone/ether mixture, then from ethyl acetate, washed with ether and dried in a vacuum oven at 60° [Chen et al. J Phys Chem 88 1631 1984 Rupert et al. J Am Chem Soc 107 2628 1985 Halpern et al. J Am Chem Soc 108 3920 1986- Allen et al. J Phys Chem 91 2320 1987]. 

Dodecyltrimethylammonium bromide [1119-94-4] M 308.4, m 246°(dec). Purified by repeated crystn from acetone. Washed with diethyl ether and dried in a vacuum oven at 60° [Dearden and Wooley J Phys Chem 91 2404 1987]. 

Fluorescein [9-(o-carboxyphenyI-6-hydroxy-3//-xantbene-3-one] [2321-07-5] M 320.0, 4950111 7.84 X 10 (in lO M NaOH), pK, 2.2, pKi 4.4, pKj 6.7. Dissolved in dilute aqueous NaOH, filtered and ppted by adding dilute (1 1) HCl. The process was repeated twice more and the fluorescein was dried at 100°. Alternatively, it has been crystd from acetone by allowing the soln to evaporate at 37° in an open beaker. Also recrystd from EtOH and dried in a vacuum oven. 

Recrysts slowly from aqueous 80% EtOH, then vacuum dried over P2O5. Alternatively, crystd from water at 55°, then dried for 6h in a vacuum oven between 60-70° at 2mm. 

Picric acid [88-89-1] M 229.1, m 122-123 , pK 0.33 (0.37). Crystd first from acetic acid then acetone, toluene, CHCI3, aqueous 30% EtOH, 95% EtOH, MeOH or H2O. Dried in a vacuum oven at 80° for 2h. Alternatively, dried over Mg(C104)2 or fused and allowed to freeze under vacuum three times. Because it is EXPLOSIVE, picric acid should be stored moistened with H2O, and only small portions should be dried at any one time. The dried acid should NOT be heated. 

Tetraethylammonium tetraphenylborate [12099-10-4] M 449.4. Recrystd from aqueous acetone. Dried in a vacuum oven at 60° for several days. Similarly for the propyl and butyl homologues. 

Tetramethylammonium tetraphenylborate [15525-13-0] M 393.3. Recrystd from acetone, acetone/CCl4 and from acetone/1,2-dichloroethane. Dried over P2O5 in vacuum, or in a vacuum oven al 60° for several days. 

Crystd repeatedly from hot water by pptn with cold EtOH or EtOH/HCl. Washed with acetone and abs EtOH and dried in a vacuum oven at 80° (see TRIEN above). 

Cupric trifluoromethylsulfonate (copper II triflate) [34946-82-2] M 361.7, pK <-3.0 (for triflic acid). Dissolve in MeCN, add dry Et20 until cloudy and cool at -20° in a freezer. The light blue ppte is collected and dried in a vacuum oven at 130°/20mm for 8h. It has Xmax 737nm (e 22.4M cm ) in AcOH. [J Am Chem Soc 95 330 1973], It has also been dried in a vessel at O.lTorr by heating with a Fischer burner [J Org Chem 43 3422 1978], It has been dried at 110-120°/5mm for Ih before use and forms a benzene complex which should be handled in a dry box because it is air sensitive [Chem Pharm Bull Jpn 28 262 I980-, J Am Chem Soc 95 330 1973]. 

Lithium iodate [13765-03-2] M 181.9. Crystd from water and dried in a vacuum oven at 60°. 

Potassium acetate [127-08-2] M 98.2, m 292 , d 1.57, pK 16 (for aquo K" "). Crystd three times from water-ethanol (1 1) dried to constant weight in a vacuum oven, or crystd from anhydrous acetic acid and pumped dry under vacuum for 30h at 100°. 

Potassium bromide [7758-02-3] M 119.0, m 734°, d 2.75. Crystd from distilled water (ImL/g) between 100° and 0°. Washed with 95% EtOH, followed by Et20. Dried in air, then heated at 115° for Ih, pulverised and heated in a vacuum oven at 130° for 4h. Has also been crystd from aqueous 30% EtOH, or EtOH, and dried over P2O5 under vacuum before heating in an oven. 

Silver acetate [563-63-3] M 166.9, pK >11.1 (for aquo Ag" " hydrolysis). Shaken with acetic acid for three days, the process being repeated with fresh acid, the solid then being dried in a vacuum oven at 40° for 48h. Has also been recrystallised from water containing a trace of acetic acid, and dried in air. 

Sodium iodide [7681-82-5] M 149.9, m 660 , b 1304 , d 3.67. Crystd from water/ethanol soln and dried for 12h under vacuum, at 70 . Alternatively, dissolved in acetone, filtered and cooled to -20°, the resulting yellow crystals being filtered off and heated in a vacuum oven at 70 for 6h to remove acetone. The Nal was then crystd from very dilute NaOH, dried under vacuum, and stored in a vacuum desiccator [Verdin Trans Faraday Soc 57 484 1961]. 

A. Triphenylcinnamylphosphonium chloride. A mixture of 40 g. (0.26 mole) of (3-chloropropenyl)benzene (Note 1) and 92 g. (0.35 mole) of triphenylphosphine (Note 2) in 500 ml. of xylene is heated at reflux for 12 hours with stirring. The mixture is allowed to cool to about 60°, and the colorless crystalline product is filtered, washed with 100 ml. of xylene, and dried in a vacuum oven at about 20 mm. pressure and 60° to constant weight. The yield is 99-101 g. (91-93%), m.p. 224-226° (Note 3). 

The alkaline filtrate and washings are combined and partially neutralized by the addition of 150-175 ml. of concentrated hydrochloric acid. Sufficient sodium sulfide solution is added to precipitate all the lead ion present (Note 6). The suspension is brought to a gentle boil to coagulate the lead sulfide, allowed to cool somewhat, and filtered with suction. The filtrate is placed in a 2-1. beaker set in an ice bath and acidified Caution in the hood) with about 150 ml. of concentrated hydrochloric acid to precipitate crude 2-hydroxyisophthalic acid monohydrate (Note 7). The suspension is cooled to 0-5° and filtered to separate the crude acid, which weighs 35-49 g. after being dried in a vacuum oven at 110°/50-150 mm. for 5 hours (Note 8). 

A. Triphenylmethylphosphonium bromide. A solution of 55 g. (0.21 mole) of triphenylphosphine dissolved in 45 ml. of dry benzene is placed in a pressure bottle, the bottle is cooled in an ice-salt mixture, and 28 g. (0.29 mole) of previously condensed methyl bromide is added (Note 1). The bottle is sealed, allowed to stand at room temperature for 2 days, and is reopened. The white solid is collected by means of suction filtration with the aid of about 500 ml. of hot benzene and is dried in a vacuum oven at 100° over phosphorus pentoxide. The yield is 74 g. (99%), m.p. 232-233°. 

A solution of 66.5 g. (1.01 moles) of 85% potassium hydroxide in 300 ml. of water in an 800-ml. beaker is heated to 60-70 , and 100 g. (0.505 mole) of commercial 1,8-naphthalic anhydride (Note 1) is stirred in. The pH of the resultant deep-brown solution is adjusted to a value of 7 (Note 2) with 6N hydrochloric acid and 3N potassium hydroxide. It is treated with 10 g. of decolorizing carbon and filtered. This operation is repeated. The filtrate is concentrated in a 1.5-1. beaker on a steam bath to about 180 ml. The concentrate is cooled to room temperature, 800 ml. of methanol is added with vigorous stirring by hand, and the mixture is cooled to 0-5°. The precipitated dipotassium naphthalate is separated by filtration, washed with 150 ml. of methanol, and dried in a vacuum oven at 150°/150 mm. The dried cream-colorcd salt weighs 130 135 g. (88 92%). 

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