Hydrazine mixture

Stone, D. A. "The Vapor Phase Autooxidation of Unsymmetrical DimethyIhydrazine and 50 Percent Unsymmetrical Dimethyl-hydrazine-50 Percent Hydrazine Mixtures," Report No. ESL-TR-80-21, April 1980. 

Nitrous oxide/hydrazine mixture combusts spontaneously. 

An oxygen/hydrazine mixture which was heated caused a violent explosion. 

It is possible for one man, simultaneously evaporating six dishes of the hydrazine mixture, to turn out from 20 to 25 runs in nine hours. The time for the evaporation of a solution, such as is mentioned in the experimental part, with a four-flame Bunsen burner, is two to three hours if the evaporation is carried out more slowly than this, the yield of product is distinctly diminished. 

Hydrazine. Mixture with anhydrous hydrazine forms sodium hydrazide, which explodes on contact with air. Mixture with hydrazine hydrate causes strongly exothermic reaction to give H2 and ammonia.15... 

Three types of PUs were prepared, based on polytetramethylene glycol(PTMG) of molec.wt. 2000, 1000 and 650. The prepolymers were prepared by reacting PTMG with MDI and were then extended with diethylene triamine(DETA) or DETA/hydrazine mixture to form the PU polymers. The polymers were then grafted with epichlorohydrin and further reacted with different... 

Fla. 2.8 Flow diagram of the program for the resolution of ammonia-hydrazine mixtures by the iterative proportional-equation method. 

Fig. 3.1 Lead cast expansion value of hydrazine nitrate-hydrazine mixture [1]...

The sulfuric acid was a 10 v/v % solution operated at S0°C and the dwell time was 10 minutes. The basic hydrazine mixture contained 32 g/L hydrazine and 16 g/L potassium hydroxide. The contact time was 10 minutes and the solution temperature was 60 C. 

Ethyl 5-trifluoromethylpyrazole-3-carboxylate was quantitatively prepared in a 1,3-dipolar cycloaddition between ethyl diazoacetate and sulphur (or bromo) derivatives of 3,3,3-trifluoropropene that act as easier to handle synthetic equivalents of 3,3,3-trifluoropropyne [35]. On top of all these studies, the most common strategy for the preparation of 3- and 5-trifluoromethylpyrazoles entails the [3 + 2] heterocy-clization of trifluoromethyl building blocks derived from p-(amino/aIkoxy/thioxy) vinylketones and 1,3-dicarbonyl with monosubstituted hydrazines. Mixtures of regioisomers are often obtained depending on the substrate, the substituent of the hydrazine, and the reaction conditions [36]. 

Mixtures of EDTA with hydrazine (frequently also containing citric acid) received extensive evaluation as solvents for deposits found in nuclear steam generators. Pitzer made the first solvents containing EDTA and hydrazine but did not conduct corrosion tests. Pocock and Leedy tested a number of potential steam-generator cleaners at 149°F and 203°F (65°C and 95°C). An EDTA/citric acid hydrazine mixture was compared with thioglycolic acid, hydroxyacetic/formic, citric/formic, and citric/formic-hydrazine. All of the solvents were inhibited with commercial inhibitors. The EDTA... 

Hydrazine Mixture 109 < 1 - - 2% Hydrazine saturated NaCi - 6% NaOH... 

Reagent A. Dissolve 0 5 g. of the powdered dinitropheny I hydrazine in a mixture of 80 ml. of concentrated hydrochloric acid and 100 ml. of distilled water by gently heating the mixture on a water-bath. Cool the solution and add 120 ml. of water. If necessary, filter the pale yellow solution. 

The 40-45 per cent, hydrazine solution may be concentrated as follows. A mixture of 150 g. (144 ml.) of the solution and 230 ml. of xylene is distilled from a 500 ml. round-bottomed flask through a well-lagged Hempel (or other efficient fractionating) column fitted into a cork covered with tin foil. All the xylene passes over with about 85 ml. of water. Upon distillation of the residue, about 50 g. of 90-95 per cent, hydrazine hydrate (5) are obtained. 

Place 1 0 ml. of hydrazine hydrate (CAUTION corrosive chemical) in a test-tube fitted with a short refiux condenser. Add 10 g. of the methyl or ethyl ester dropwise (or portionwise) and heat the mixture gently under refiux for 15 minutes. Then add just enough absolute ethanol through the condenser to produce a clear solution, refiux for a further 2-3 hours, distil oflF the ethyl alcohol, and cool. Filter oflF the crystals of the acid hydrazide, and recrystallise from ethanol, dilute ethanol or from water. 

Place 36 -0 g. of redistilled acetophenone, b.p. 201° (Section IV,136), 300 ml. of diethylene glycol, 30 ml. of 90 per cent, hydrazine hydrate and 40 g. of potassium hydroxide pellets in a 500 ml. Claisen flask provided with a reflux condenser and a thermometer dipping into the liquid (compare Fig. Ill, 31, 1). Warm the mixture on a boiling water bath until most of the potassium hydroxide has dissolved and then reflux (free flame) for one hour. Arrange the apparatus for distillation and distil until the temperature in the liquid rises to 175° (1) keep the distillate (ca. 50 ml.). Replace the reflux condenser in the flask and continue the refluxing for 3 hours. 

Suspend 35 g. of finely-powdered hydrazine sulphate in 125 ml. of hot water contained in a 400 ml. beaker, and add, with stirring, 118 g. of crystallised sodium acetate or 85 g. of potassium acetate. Boil the mixture for 5 minutes, cool to about 70°, add 80 ml. of rectified spirit, filter at the pump and wash with 80 ml. of hot rectified spirit. Keep the filtered hydrazine solution for the next stage in the preparation. 

Equip a 1 Utre three-necked flask or a 1 litre bolt- head flask with a reflux condenser and a mercury-sealed stirrer. Dissolve 50-5 g. of commercial 2 4-dinitro-l-chlorobenzene in 250 ml. of rectified spirit in the flask, add the hydrazine solution, and reflux the mixture with stirring for an hour. Most of the condensation product separates during the first 10 minutes. Cool, filter with suction, and wash with 50 ml. of warm (60°) rectified spirit to remove unchanged dinitrochlorobenzene, and then with 50 ml. of hot water. The resulting 2 4-dinitrophenylhydrazine (30 g.) melts at 191-192° (decomp.), and is pure enough for most purposes. Distil oflF half the alcohol from the filtrate and thus obtain a less pure second crop (about 12 g.) recrystallise this from n-butyl alcohol (30 ml. per gram). If pure 2 4-dinitrophenylhydrazine is required, recrystallise the total yield from n-butyl alcohol or from dioxan (10 ml. per gram) this melts at 200° (decomp.). 

Stir a mixture of 2-4 g. of powdered hydrazine sulphate, 18 ml. of water and 2-4 ml. of concentrated aqueous ammonia (sp. gr. 0-88), and add 4-6 g. (4 4 ml.) of benzaldehyde (free from benzoic acid) dropwise, with stirring, over a period of 30-60 minutes. Stir the mixture for a further hour, collect the solid by suction filtration and wash it with water. RecrystalUse from 8 ml. of rectified spirit. The 3 ield of benzalazine (yellow needles), m.p. 92-93°, is 3-6 g. 

Benzil monohydrazone. Method 1. Boil a mixture of 26 g. of hydrazine sulphate, 55 g. of crystallised sodium acetate and 125 ml. of water for 5 minutes, cool to about 50°, and add 115 ml. of methyl alcohol. Filter off the precipitated sodium sulphate and wash with a little alcohol. Dissolve 25 g. of benzil (Section IV,126) in 40 ml. of hot methyl alcohol and add the above hydrazine solution, heated to 60°. Most of the benzil hydrazone separates immediately, but reflux for 30 minutes in order to increase the yield. Allow to cool, filter the hydrazone and wash it with a httle ether to remove the yellow colour. The yield is 25 g., m.p. 149-151° (decomp.). 

The acetone test reagent consists of a 0 1 per cent, solution of 2 4-dinitro-phenylhydrazine and is prepared as follows Dissolve 0-25 g. of 2 4-dinitrophenyl-hydrazine in 60 ml. of water and 42 ml. of concentrated hydrochloric acid by warming on a water bath cool the clear yellow solution and dilute to 250 ml. with water. The acetone test is considered negative when 5 ml. of the reagent and 4-5 drops of the distillate give no cloudiness or precipitate of acetone 2 4-dinitro-phenylhydrazone within 30 seconds. After a negative test is obtained, it is stron y recommended that the mixture in the flask be refluxed for 5-10 minutes with complete condensation and then to collect a few drops of distillate for another test. If no acetone is now detected, the reduction is complete. 

Girard s reagent P , C5H5NCH2C0NHNH2 C1. In a 1-htre threenecked flask, equipped as in the previous preparation, place 200 ml. of absolute ethyl alcohol, 63 g. (64 -5 ml.) of pure anhydrous pyridine and 98 - 5 g. (84 5 ml.) of ethyl chloroacetate. Heat the mixture under reflux for 2-3 hours until the formation of the quaternary salt is complete acidify a small test-portion with dilute sulphuric acid it should dissolve completely and no odour of ethyl chloroacetate should be apparent. Cool the mixture in ice and salt. Replace the thermometer by a dropping funnel, and add a solution of 40 g. of 100 per cent, hydrazine hydrate in 60 ml. of absolute ethanol all at once. A vigorous exothermic reaction soon develops and is accompanied by vigorous effervescence. The pro duct separates almost immediately. When cold, filter with suction, wash... 

With Stirring, hydrazine hydrate (4 ml in 30 ml of THh ) was added over 60 min. The reaction mixture was then cooled to room temperature and filtered through Celite. The filtrate was concentrated in vacuo and the residue purified by chromatography through silica gel using 10% ether in hexane for elution. The fractions containing product were combined and evaporated to give the product as a clear oil (2.94g, 50%). 

Heating diethyl 2-phenyl-4,5-thiazoledicarboxylate (16) in alcohol with an excess of hydrazine hydrate gave a mixture of cyclohydrazide (17) and the open-chain 2-phenyl-4,5-thiazoledicarboxylic dihydrazide (18) (Scheme 11) (5). The relative amounts of these two products depended on... 

Eig. 1. Ereezing-point diagram for hydrazine—water mixtures. 

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