Ethylene bromide

Heat the flask cautiously at first and then to such a temperature that ethylene is given off freely. After the gas begins to come off the apparatus needs little attention if it is so placed that the flame is not in a draught if this is the case, use a chimney so that a steady heat may be obtained. Heat as long as ethylene is formed from one-half hour to an hour is usually sufficient. If the bromine has not been used up when the ethylene ceases to be evolved, remove the tubes containing ethylene bromide, and under the hood transfer the liquids to a flask. Wash by decantation with a dilute solution of sodium hydroxide until the heavy oil is colorless, and then once with water. Separate the bromide, and dry it with calcium chloride. After standing an hour or 

Ethylene bromide melts at 8.4° and boils at 132°, and has the specific gravity of 2.189 at 15°. The yield in this preparation is about 55 grams. 

Heat the flask at the lowest temperature at which ethylene is freely evolved. It is very essential to avoid over-heating, which results in frothing and the liberation of carbon. If this occurs, the contents of the flask should be poured out and ethylene should be prepared from a new mixture. When the bromine is decolorized, treat the product as directed in (a) above. 

—Sand is added to the flask to distribute the heat more evenly and, thus, to assist in preventing frothing. In the presence of aluminium sulphate, the decomposition of alcohol into ethylene takes place at about 140°, whereas in the absence of the sulphate a temperature of about 180° is required. At the lower temperature carbonization is not apt to occur. 

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Bromoacetic acid can be prepared by the bromination of acetic acid in the presence of acetic anhydride and a trace of pyridine (55), by the HeU-VoUiard-Zelinsky bromination cataly2ed by phosphoms, and by direct bromination of acetic acid at high temperatures or with hydrogen chloride as catalyst. Other methods of preparation include treatment of chloroacetic acid with hydrobromic acid at elevated temperatures (56), oxidation of ethylene bromide with Aiming nitric acid, hydrolysis of dibromovinyl ether, and air oxidation of bromoacetylene in ethanol. 

The simplest analytical procedure is to oxidize a sample in air below the fusion point of the ash. The loss on ignition is reported as graphitic carbon. Refinements are deterrninations of the presence of amorphous carbon by gravity separation with ethylene bromide, or preferably by x-ray diffraction, and carbonates by loss of weight on treating with nitric acid. Corrections for amorphous carbon and carbonates are appHed to the ignition data, but loss of volatile materials and oxidation may introduce errors. 

A method for physically separating turbostratic carbon and graphite involves shaking a sample into suspension in ethylene bromide of sp gr 2.17 and centrifliging. The method is unreflable except where fine carbon and coarse graphite are admixed it can be an aid in quaUtative examination. 

Chemical DesignationsBromofiime 1,2-Dibromoethane sym-Dibromoethane Dowfume 40, W-10,W-15, W-40 Ethylene bromide Glycol dibromide Chemical Formula BrCHjCH Br. Observable Characteristics - Physical State (as normally shipped) Liquid Color Colorless Odor Mildly sweet like chloroform. 

R. T. Dillon (1932) studied the reaetion between ethylene bromide and potassium iodide in 99% methanol with the following data ... 

A very obvious way to change die measurement range and sensitivity of a fluid manometer is by using fluids of different densities. There are only a few suitable liquids with specific gravit> between that of water and mercury. Ethylene bromide has a specific gravity of 2.2 and acetylene tetrabromide 3.0., but they are corrosive. 

Reaction.—a too c.c. flask to a short upright condenser (see Fig. 86) and to the upper end of the condensei attach a vertical delivery tube, dipping into an ammoniacal cuprous chloride solution. Pour 2—3 c.c. of ethylene bromide into the flask with 4 times its volume of strong methyl alcoholic potash, which is prepared by boiling methyl alcohol with excess of caustic potash on the water-bath with upright condenser. On gently heating, a rapid evolution of acetylene occurs and the characteristic brown copper compound (C2H,Cu,HjO) is precipitated from the cuprous chloride solution. 

These compounds yield, on hydrolysis, the free acids, which, like all acids containing two carbo.xyl groups attached to the same carbon atom, lose COj on heating. Thus, ethyl malonic acid yields butyric acid. In this way the synthesis of monobasic acids may be readily effected. Malonic ester, moreover, may be used in the preparation of cyclic compounds as well as of tetrabasic and also dibasic acids of the malonic acid series ( Perkin). To give one illustration malonic ester, and ethylene bromide in presence of sodium alcoholate, yield triniethyleiic dicarbo.xylic ester and tetramethylene tetracarbo.xylic ester. The first reaction takes place in two steps,... 

Contains Halogen.—Halogen compounds may be n/ly/em aryl or add haUdc tQ ha/oyru a[Pg.341]

Ethyl alcohol, 49 Ethyl benzene, 141 Ethyl benzoate, 209 Ethyl bromide, 54 Ethylene bromide, 62 Ethyl ether, 59 Ethyl malonate, 96 Ethyl malonic acid, 97 Ethyl potassium sulphate, 50 Ethyl tartrate, 115 rotation of, 120 Lykman depressimeter, 37... 

Brom-. of or combined with bromine bromo- (as Brombenzoeadure, bromobenzoic acid) bromide of (as Brombaryum, barium bromide). -ammoD, tn., ammonium, n. ammonium bromide, -antimon, n. antimony bromide, -arsen, n., -arsem k, tn. arsem c bromide. ather, tn. ethyl bromide, -athyl, n. ethyl bromide. athylen, n. ethylene bromide, athyiformin, n. Pharm.) bromalin. -atom, n. bromine atom, -baryum, n. barium bromide. beere, /. blackberry, brombeerrot, a. blackberry ed. 

D) Preparation of 4-[1 -Methyl-Piperidyl-(4 )]-9,10-Dihydro-4H-Benzol4,5]Cyciohepta[1,2-b] Thiophen-(4)-ol 0.94 g of magnesium filings which have been activated with iodine are covered with a layer of absolute tetrahydrofuran and etched with a few drops of ethylene bromide. A solution of 5.0 g of 1-methyl-4-chloropiperidine in 5 ml of tetrahydrofuran is then added dropwise and boiling then effected for a further hour under reflux. After cooling to room temperature, the solution of 4.5 g of 9,lO-dihydro-4H-benzo[4,5] cyclohepta[1,2-b] thio-phen-(4)-one in 5 ml of tetrahydrofuran is added dropwise. 

The exothermic reaction occurs at approximately 4 atmospheres and 40-50°C in the presence of EeCls, CuCl2 or SbCls catalysts. Ethylene bromide may also be used as a catalyst. 

Bromoethylamine hydrobromide has been prepared by the reaction of potassium phthalimide with ethylene bromide, followed by hydrolysis,1 by the addition of hydrogen bromide to ethyleneimine,2 and by the present method.3... 

Prepd by adding dropwise a satd aq soln of KCN to a boiling soln of ethylene bromide in ethanol (Ref 2)... 

Ethane, bromo-, 55, 91, 92 Ethane, 1,2-dibromo-, 1,2-ethanediyl bromide [Ethylene bromide], 55, 94... 

Ethyl 2-diazoacetoacetate, 59, 69 Ethylene, 58, 73 Ethylene bromide, 55, 94 Ethylene carbonate, 58, 97... 

In 1863 Husemann prepared an intermediate, to which he assigned the formula C2H4S, by the action of sodium sulfide on ethylene bromide. From it he obtained the cyclic dimer, dithiane, by distillation. Mans-feld (1886) reinvestigated the intermediate and concluded that it is a polymer. As a reminder of the significance of the term polymer at that time it is to be noted, however, that Mansfeld suggested the cyclic trimeric formula for the intermediate, which is now known to be a linear polymer. Other polymers prepared similarly by Husemann (1863) include methylene sulfide (—CH2—S—)a and methylene tri-thiocarbonate (—CH2—S—CS—S—) . Neither was recognized as a polymer, and neither has since been investigated from this standpoint. 

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