Benzidine hydrochloride

Dissolve 9-5 g. of hydrazobenzene (Section IV,87) in the minimum volume of ether (about 90 ml. are usually required), and add this solution in small portions from a separatory funnel to 100 ml. of ice-cold dilute hydrochloric acid (1 1) contained in a 350 ml. conical flask stopper the flask and shake after each addition. Benzidine hydrochloride separates out during the reaction. After all the hydrazobenzene has been introduced, add 50 ml. of concentrated hydrochloric acid and allow the mixture to stand for 30 minutes in ice water. Filter the benzidine hydrochloride at the pump, wash it first with 20 ml. of dilute hydrochloric acid (1 1) and then with two or three 20 ml. portions of ether (to dissolve any unchanged hydrazobenzene) (1). 

Benzidine hydrochloride solution (for sulfate determination) mix 6.7 g of benzidine [Ci2H8(NH2)2] or 8.0 g of the hydrochloride [Ci2H8(NH2)2 2HC1] into a paste with 20 mL of water add 20 mL of HCl (sp. gr. 1.12) and dilute the mixture to 1 liter with water each mL of this solution is equivalent to 0.00357 g H2SO4. 

Benzidine-based dyes Benzidine hydrochloride Benzidines Benzidine Yellows AAMX Benzil [134-81-6]... 

Smectite [12199-37-0] from an oxidized outcrop is stained light blue by a dilute solution of benzidine hydrochloride. The color does not arise from smectite specifically, but from reaction of a high oxidation state of elements such as Fe " and Mn " (46)46. 

Benzidine.—Five grams of powdered hydrazobenzene are shaken with 125 c.c. hydiochloric acid (jpei cent.) at 20—30. In a quarter to half an hour the substance will have completely dissolved. Finally, the mi.xtuie is heated to 45—50, a little water added to ledissolve any benzidine hydrochloride, and filtered warm. The benzidine is precipitated from the solution of the hydrochloride by adding to the cold solution an e.xcess of caustic soda solution. It is filtered and washed free from alkali, and lecrystallised from boiling water or dilute alcohol. It crystallises m plates with nacreous lustre, m. p. 127°. 

Hydrazobenzene (9-2 g.) dissolved in the minimum quantity of ether is added drop by drop with shaking to 100 c.c. of ice-cold, approximately 7 N-hydrochloric acid (concentrated acid diluted with an equal volume of water). Crystalline benzidine hydrochloride separates and, after 50 c.c. of concentrated hydrochloric acid have been added and the mixture has stood for half an hour, the hydrochloride is filtered at the pump, and washed, first with 7 N-hydro-chloric acid and then with a little ether. Yield 9-10 g. The hydrochloride can be recrystallised by dissolution in hot water and addition of concentrated hydrochloric acid to the slightly cooled solution. 

Other reagents which may be applied to the volumetric determination of sulphuric acid and sulphates are barium chromate and benzidine. In the case of the former, the solution of sulphate is precipitated by a solution of barium chromate in hydrochloric acid on subsequent neutralisation of the filtrate, a quantity of chromic acid, equivalent to the barium sulphate which has been precipitated, remains in solution and may be estimated iodometrically.6 Benzidine, on the other hand, is an organic base which forms a very sparingly soluble sulphate the solution of mineral sulphate is treated with a solution of benzidine hydrochloride and the precipitated benzidine sulphate removed by filtration when subsequently suspended in pure water the benzidine sulphate undergoes hydrolysis to a sufficient extent to permit titration of the sulphuric acid with standard alkali.7 Lead nitrate may also be... 

Methods that attempt to directly measure the sulfonate content of lignin in pulps must overcome the challenge of distinguishing sulfonate from accompanying carboxylate groups. One such method (Sjostrom and Enstrom 1966, Sjostrom et al. 1965) is based on the concept that, under acidic conditions, benzidinium ions form salts only with the sulfonate groups. The pulp is saturated with an aqueous solution of benzidine hydrochloride and washed with water to remove excess reagent the benzidinium ions are eluted with hydrochloric acid and determined by UV spectrophotometry. 

Benzidine hydrochloride solution white precipitate of benzidine sulphate. (DANGER THE REAGENT IS CARCINOGENIC.)... 

Benzidine hydrochloride (0-5%). Dissolve 0-5 g benzidine (4-4 -diamino-diphenyl), H2N.C6H4.C6H4.NH2, in 2 ml of 1 1 hydrochloric acid and dilute the solution with water to 100 ml. (DANGER THE REAGENT IS CARCINOGENIC.)... 

Rearrangement of Hydrazobenzene to Benzidine. The o-dichlorobenzene solution of hydrazobenzene is mixed with kn equal weight of finely pulverized ice to which 300 cc. concentrated hydrochloric acid has been added. The benzidine hydrochloride which is formed (along with the by-product, diphenyline) goes into the water layer. After 3 hours, the mixture is warmed to 80°, 500 cc. hot water is added, and the o-dichlorobenzene layer is separated and washed twice with water. If the water layer is cloudy, it is filtered hot. 

BENZIDINEDICARBOXYUC ACID see BFX250 BENZIDINE HYDROCHLORIDE see BBX750 BENZIDINE SULFATE see BBYOOO BENZIDINE SULPHATE and HYDRAZINE-BENZENE... 

Chemical analysis a sodium thiosulfate volumetric method for Cu, x-ray fluorescence for Zn, carbon and sulfur analysis (LECO CS-344) and a benzidine hydrochloride precipitation method for S04 X-ray diffraction for the measurement of Cu crystallite size and bulk component analysis scanning electron microscope (Phillip SEM-5Q5) XPS spectrometer (KRATOS XSAM 800). 

A) Preparation of Benzidine (Sm.). Prepare about 2 g of hydrazobenzene according to Experiment 30. Dissolve in a small flask 2 g of hydrazobenzene in 15 ml of ether. Place 8 ml of concentrated hydrochloric acid and 8 ml of water in an eight-inch test tube and provide with solid rubber stopper. Cool in an ice-salt mixture. Add the ethereal solution slowly by means of a dropper to the cold diluted acid, and shake vigorously after each addition. When all the hydrazobenzene solution has been added, allow to stand 10 minutes, and add 10 ml of concentrated hydrochloric acid. Allow the tube to remain in the cold bath 15 minutes longer. Filter the benzidine hydrochloride with suction. Wash the crystals with 5 ml of dilute (1 1) hydrochloric acid and finally with two 5 ml portions of ether, and dry on a paper disc. The yield is about 2 g. 

B) Reduction of Benzidine to Biphenyl (Sm.). Place in a small beaker (150 ml) 2 g of benzidine hydrochloride, 10 ml of water, and 4 ml of concentrated hydrochloric acid. Cool to 0° and add 5 g of ice and a solution of 1.1 g of sodium nitrite dissolved in 5 ml of water. Stir until the diazotization is complete, that is, until all the material has dissolved, and a test with iodide paper shows presence of nitrous acid. Add 15 ml of ethyl alcohol, and sift in 5 g of zinc dust, in small portions over a period of 5 minutes, stirring after... 

Benzidine hydrochloride, 1% solution. Add 0.5 g of the reagent to 50 ml of 0.5 M HCl, heat to boiling, cool, and filter. Keep the filtrate in an amber-glass bottle. 

When a solution of hydrazobenzene in the minimum of ether is dropped into ice-cold 18% hydrochloric acid, crystalline benzidine hydrochloride separates.8815... 

Potassium hydroxide Potassium chloride Methylene blue Desogren Geisry Barium chloride Benzidine hydrochloride Ferric chloride Phosphotunsrstic acid Tannic acid Ruthenium re l Thorium nitrate Hexyl nitrate... 

Benzidine, 3,3 -dichloro-, dihydrochloride. See 3,3 -Dichlorobenzidine dihydrochloride Benzidine dihydrochloride CAS 531-85-1 EINECS/ELINCS 208-519-6 Synonyms Benzidine hydrochloride (1,1 -Biphenyl)-4,4 -diamine, dihydrochloride Empihcal C12H12N2 2HCI Formula H2NC6H4C6H4NH2 2HCI Properties Wh. cryst. powd. sol. in alcohol sol. 5-10 mg/ml in DMSO sol. 1-5 mg/ml in water sol. <... 

Benzldine-2,2 -disulfonic acid. See 2,2 -Benzidinedisulfonic acid Benzidine hydrochloride. See Benzidine dihydrochloride... 

Procedure. The reaction is conducted on a spot plate. A drop of the test solution is treated with a drop of 25 % potassium cyanide solution and a drop of a mixture of 25 % pyridine and 2 % benzidine hydrochloride solution. If elementary chlorine or bromine is present, a red precipitate or color results. Limit of Identification 2.6 y chlorine or bromine... 

Oxalates can be removed by igniting before beginning the test. In the presence of sulfates, benzidine hydrochloride should be added to the test solution, and then a drop of the benzidine sulfate suspension placed on the reagent paper. Any yellow coloration of the red reagent paper caused by fluorine can easily be seen on the under side of the paper. 

Benzidine hydrochloride solution (for sulfate determination). Prepare a paste of 8 g of benzidine hydrochloride (Cj2Hg(NHj)2 2HCl) and 20 mL of distilled water, add 20 mL of 20% (mass/mass) HCl and dilute to 1 L with distilled water. Each mL of this solution is equivalent to 0.00357 g of H SO. Note that the reagent is often called benzidine dihydrochloride. Bertrand s reagent (glucose estimation). Consists of the following solutions ... 

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