Heating heat guns

Method 2. In the apparatus described above is placed 4.8-5.0g. ( 0.2 g.-atorn) of clean sodium and 8.0-8.2 g. ( 0.2 g.-atom) of clean potassium (Ilotes 3, 4). The flask is heated with a heat gun to form the low-melting alloy, and then 300-350 ml. of anhydrous ether is added from a freshly opened can. The stirrer is operated at full speed until the alloy is dispersed and then at a slower speed for the remainder of the reaction (Notes 5, 6). A mixture of 17.4 g. (0.1 mole) of diethyl succinate (Note 7), 44g. (0.4 mole) of chlorotrimethylsilane (Note 8), and 125 ml. of anhydrous ether is then added at a rate sufficient to keep the reaction under control (Note 14). The purple mixture is stirred for another 4-6 hours (Note 9) and then filtered and washed as above in a nitrogen dry-box (Note ll). The product is distilled as above forerun 0.5-2 g. to 80° (10 mm.) and then at 82-86° (10 mm.) as a colorless liquid, 13.8-16.1 g. (60-70%), 1.4323-1.4330 (Notes 15-19). 

Heat-shrink crosslinked polyethylene DIN 30672 Flame or heat gun in fieid 1-25-2-25 Utiiised for coating of field weld joints and repairs on extruded polyethylene coated pipes. Careful application required to achieve consistent bond. 

The last traces of product can be driven into the receiver by warming the stillhead with a heat gun. 

The glass filter funnel containing Celite was preheated using a heat gun to avoid precipitation of product in the funnel. After filtration, an additional preheated mixture of 120 mL of heptane and 30 mL of toluene was passed through the Celite using suction. A precipitate forms in the filtrate, which is redissolved by heating to reflux. 

Caution should be used evaporating the solvent, as the residue tends to foam upon concentration. Concentration is carried out by rotary evaporation and then for 30 min at high vacuum (1 mm) while warming with a heat gun to remove all of the methanol. 

Fischbein A, Anderson KE, Sassa S. et al. 1981. Lead poisoning from do-it- yourself heat guns for removing lead-based paint Report of two cases. Environ Res 24 425-431. 

A. Trifluoromethanesulfonic Anhydride. To a dry, 100-ml., round-bottomed flask are added 36.3 g. (0.242 mole) of trifluoromethane-sulfonic acid (Note 1) and 27.3 g. (0.192 mole) of phosphorus pentoxide (Note 2). The flask is stoppered and allowed to stand at room temperature for at least 3 hours. During this period the reaction changes from a slurry to a solid mass. The flask is fitted with a short-path distilling head and then heated first with a stream of hot air from a heat gun and then with the flame from a small burner. The flask is heated until no more trifluoromethanesulfonic anhydride distills, b.p. 82-115°. The yield of the anhydride, a colorless liquid, is 28.4-31.2 g. (83-91%). Although this product is sufficiently pure for use in the next step of this preparation, the remaining acid may be removed from the anhydride by the following procedure. A slurry of 3.2 g. of phosphorous pentoxide in 31.2 g. of the crude anhydride is stirred at room temperature in a stoppered flask for 18 hours. After the reaction" flask has been fitted with a short-path distilling head, it is heated with an oil bath to distill iD.7 g. of forerun, b.p. 74—81°, followed by 27.9 g. of the pure trifluoromethanesulfonic acid anhydride, b.p. 81-84° (Note 3). 

It is important that the starting materials be melted prior to the addition of nitric acid. Heating above 85°C during the reaction causes the product to sublime on the sides of the flask and in the condenser, potentially clogging it and leading to pressure build-up in the reaction flask. The sublimed acid may be melted back into the reaction mixture with judicious use of a heat gun. 

The evacuated apparatus is dried with a flameless heat gun at 150°C and then flushed with dry argon. An atmosphere of dry argon is maintained during the course of the reaction. The jacket of the dropping funnel is charged with acetone and dry ice or with ethanol and liquid nitrogen. 

A. Preparation of an ether solution of phenylmagnesium bromide (Note 1). Ether (100 mL) is added to magnesium (Mg) turnings (74.6 g, 3.07 mol) in a dry, S-L flask equipped with an overhead stirrer, reflux condenser, and addition funnel. Iodine (several crystals) is added and the mixture is stirred for several minutes (the color dissipates). Bromobenzene (9.23 mL, 13.76 g, 87.64 mmol) is added and the mixture is heated with a heat gun to initiate the reaction. A solution of bromobenzene (322.8 mL, 481 g, 3.06 mol) in ether (600 mL) is added dropwise over 2.75 hr, maintaining a gentle reflux. The dark brown mixture is stirred an additional 3 hr at ambient temperature under nitrogen and then cooled in an ice/methanol bath to 0°C. 

The Claisen distillation head was filled with glass wool to avoid formation of foam. The checkers found that constant heating of the distillation apparatus with a heat gun greatly facilitates the rate of distillation and minimizes the column holdup. 

The spectra obtained are completely reversible during observation times of under one hour. For longer time periods of oxygen exposure in the dark, the DC offset signal increases slowly, 5-10 5 of the Langmuir isotherm value per hour. It increases more quickly if the porphyrin films are heated for several minutes with a heat gun, while under oxygen. 

The use of a heat gun aids the distillation because the product is extremely viscous. 

The condenser 1s not cooled and the collector tip is at times gently heated with a heat gun to prevent crystallization of 4-methoxyan11ine in the distillation apparatus. 

A. (S)-3-(tert-Butyloxycarbonylamino)-1-diazo-4-phenylbutan-2-one. A 1-L, three-necked, round-bottomed flask is equipped with a magnetic stirring bar, nitrogen gas inlet, bubble counter and a rubber septum on the center neck. The apparatus Is dried under a rapid stream of nitrogen with a heat gun. After the flask is cooled to room temperature, the... 

Caution. Considerable frothing of the viscous phosphoric acid melt will occur during this operation. Careful control of the vacuum is necessary to prevent contamination ofV(COfr by the reaction mixture melt. Do not heat the water bath above 40° C, and do not use a heat gun or other external heat source to facilitate the transfer, since V(COfr will quickly decompose to a vanadium... 

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