531-85-1

Basic information

• Product Name: Benzidine dihydrochloride
• Synonyms: benzidine2hcl;benzidinedihydrochloridehumancarcinogen;dihidroclorurodebenzidina;p,p’-Diaminodiphenylhydrochloride;P,P'-DIAMINOBIPHENYL DIHYDROCHLORIDE;4,4'-Diaminobiphenyl dihydrochloride;4,4′-Diaminodiphenyl dihydrochloride;[1,1'-biphenyl]-4,4'-diamine dihydrochloride
• CAS NO: 531-85-1
• Molecular Formula: C₁₂H₁₄N₂*2Cl
• Molecular Weight: 257.16
• EINECS: 208-519-6
• Product Categories: Intermediates of Dyes and Pigments
• Mol File: 531-85-1.mol

Chemical Properties

• Melting Point: ≥300 °C
• Boiling Point: 358.7°Cat760mmHg
• Flash Point: 203.5°C
• Appearance: WHITE TO OFF-WHITE POWDER
• Density: 1.156g/cm³
• Vapor Pressure: 2.5E-05mmHg at 25°C
• Water Solubility: 0.1-0.5 g/100 mL at 23.5 ºC
• BRN: 3914846
• CAS DataBase Reference: Benzidine dihydrochloride(CAS DataBase Reference)
• NIST Chemistry Reference: Benzidine dihydrochloride(531-85-1)
• EPA Substance Registry System: Benzidine dihydrochloride(531-85-1)

Safety Data

• Hazard Codes: T,N,Xn
• Statements: 45-22-50/53-36/37/38-20/21/22
• Safety Statements: 53-45-60-61-36-26
• RIDADR: UN 2811 6.1/PG 2
• WGK Germany: 3
• RTECS: DD0600000
• Hazardous Substances Data: 531-85-1(Hazardous Substances Data)

Usage

Uses

Used in Dye Industry:
Benzidine dihydrochloride is used as a key intermediate for the production of dyes, particularly in the manufacturing of azo dyes. Its chemical properties allow it to form a wide range of colorants, making it a valuable component in the dye industry.
Used in Environmental Testing:
Benzidine dihydrochloride is also utilized in environmental testing as a reference compound for the detection and quantification of benzidine and its derivatives in various samples. This is crucial for assessing the presence of potentially harmful substances in the environment and ensuring compliance with regulatory standards.

Air & Water Reactions

Benzidine dihydrochloride may be sensitive to prolonged exposure to light and air. Slightly soluble in water.

Reactivity Profile

Acidic organic/inorganic salts, such as Benzidine dihydrochloride, are generally soluble in water. The resulting solutions contain moderate to high concentrations of hydrogen ions and have pH's of less than 7.0. They react as acids to neutralize bases. These neutralizations generate heat, but less or far less than is generated by neutralization of inorganic acids, inorganic oxoacids, and carboxylic acid. They usually do not react as either oxidizing agents or reducing agents but such behavior is not impossible. Many of these compounds catalyze organic reactions.

Fire Hazard

Flash point data for Benzidine dihydrochloride are not available; however, Benzidine dihydrochloride is probably combustible.

Safety Profile

Suspected carcinogen with experimental carcinogenic and tumorigenic data. Human mutation data reported. When heated to decomposition it emits very toxic fumes of HCl and NOx.

Purification Methods

Benzidine dihydrochloride [531-85-1] M 257.2, m >250o(dec). Crystallise the salt by dissolving in hot H2O, and adding conc HCl to the slightly cooled solution. CARCINOGENIC.[Beilstein 13 IV 365.]

InChI:InChI=1/C12H12N2.ClH/c13-11-5-1-9(2-6-11)10-3-7-12(14)8-4-10;/h1-8H,13-14H2;1H

Synthetic route

N,N-dichloro-p-toluenesulfonamide (473-34-7) + chloroform (67-66-3) + diphenyl hydrazine (122-66-7) → benzidine dihydrochloride (531-85-1) + toluene-4-sulfonamide (70-55-3) + trans-azobenzene (17082-12-1)

p,p'-diaminobiphenyl (92-87-5) → benzidine dihydrochloride (531-85-1)

Conditions	Yield
With hydrogenchloride In water

disodium 9,10-anthraquinone-2,6-disulfonate (853-68-9) + benzidine dihydrochloride (531-85-1) → C40H20N2O14S4(4-)*4Na(1+)

Conditions	Yield
In ethanol; water for 2h; Reflux;	82%

benzidine dihydrochloride (531-85-1) + azulene (275-51-4) → bis(azulene-1-azo)-4,4'-biphenyl

Conditions	Yield
Stage #1: benzidine dihydrochloride With hydrogenchloride; water; sodium nitrite at 0℃; Diazotization; Stage #2: azulene With sodium acetate In ethanol at 20℃; for 0.5h; Arylation;	78%
Stage #1: benzidine dihydrochloride With hydrogenchloride; water; sodium nitrite at 0℃; Diazotization; Stage #2: azulene With sodium acetate In ethanol at 20℃; for 0.5h; Arylation; Further stages.;	78%

benzidine dihydrochloride (531-85-1) + 5-hydroxy-3-methyl-1-(pyrid-2-yl)-1H-pyrazole (38695-92-0) → C30H24N10O2

Conditions	Yield
Stage #1: benzidine dihydrochloride With hydrogenchloride; sodium nitrite In water at 0 - 5℃; Stage #2: 5-hydroxy-3-methyl-1-(pyrid-2-yl)-1H-pyrazole With sodium hydroxide; aluminium trichloride In water for 0.5h; pH=8.0 - 8.5; cooling;	77%

benzidine dihydrochloride (531-85-1) + 1-(4-chlorophenyl)-3-methyl-2-pyrazolin-5-one (13024-90-3) → C32H24Cl2N8O2

Conditions	Yield
Stage #1: benzidine dihydrochloride With hydrogenchloride; sodium nitrite In water at 0 - 5℃; Stage #2: 1-(4-chlorophenyl)-3-methyl-2-pyrazolin-5-one With sodium hydroxide; aluminium trichloride In water for 0.5h; pH=8.0 - 8.5; cooling;	76%

benzidine dihydrochloride (531-85-1) + 1-(4-methoxyphenyl)-3-methyl-2-pyrazolin-5-one (60798-06-3) → C34H30N8O4

Conditions	Yield
Stage #1: benzidine dihydrochloride With hydrogenchloride; sodium nitrite In water at 0 - 5℃; Stage #2: 1-(4-methoxyphenyl)-3-methyl-2-pyrazolin-5-one With sodium hydroxide; aluminium trichloride In water for 0.5h; pH=8.0 - 8.5; cooling;	71%

di-tert-butyl dicarbonate (24424-99-5) + benzidine dihydrochloride (531-85-1) → di-tert-butyl [1,1’-biphenyl]-4,4’-diyldicarbamate

Conditions	Yield
With 4-methyl-morpholine; dmap In 1,2-dimethoxyethane at 55℃; for 40h;	64%

tetrakis(4-sulfophenyl)methane + benzidine dihydrochloride (531-85-1) → C25H20O12S4*2C12H12N2

Conditions	Yield
In methanol; water at 20℃;	58%

hydrogenchloride (7647-01-0) + benzidine dihydrochloride (531-85-1) + cadmium(II) chloride (10108-64-2) → benzidine diammonium tetrachloride cadmate

Conditions	Yield
In methanol excess of CdCl2 with 2 drops of concd.HCl in CH3OH added to soln. of ligand in CH3OH, stirred for 0.5 h; filtered, crystd., XRD;	52%

phosgene (75-44-5) + benzidine dihydrochloride (531-85-1) → biphenyl-4,4'-diyl diisocyanate (2761-22-0)

Conditions	Yield
With bromobenzene

undec-10-enoyl chloride (38460-95-6) + benzidine dihydrochloride (531-85-1) → N,N'-biphenyl-4,4'-diyl-bis-undec-10-enamide

Conditions	Yield
With diethyl ether; sodium carbonate

Boc-Aoa-OPcp (39910-60-6) + benzidine dihydrochloride (531-85-1) → C26H34N4O8 (33809-63-1)

Conditions	Yield
With triethylamine In 1,4-dioxane

potassium cyanide (151-50-8) + benzidine dihydrochloride (531-85-1) → (1,1'-biphenyl)-4,4'-dicarbonitrile (1591-30-6)

Conditions	Yield
(i) aq. HCl, NaNO2, (ii) /BRN= 4652394/, aq. CuCN; Multistep reaction;

benzidine dihydrochloride (531-85-1) → 4,4'-Bis-(phenyl-trans-azo)-biphenyl (120623-26-9)

Conditions	Yield
Multi-step reaction with 2 steps 1: bromobenzene 2: benzene / 140 °C / unter Druck View Scheme

benzidine dihydrochloride (531-85-1) → N,N'-biphenyl-4,4'-diyl-bis-carbamic acid di-[1]naphthyl ester

Conditions	Yield
Multi-step reaction with 2 steps 1: bromobenzene 2: bromobenzene View Scheme

benzidine dihydrochloride (531-85-1) → 1,1'-(4,4'-biphenylene)bis(3-(naphthalen-1-yl)urea)

Conditions	Yield
Multi-step reaction with 2 steps 1: bromobenzene 2: bromobenzene View Scheme

benzidine dihydrochloride (531-85-1) → 1,1'-(4,4'-biphenylene)bis(3-phenylurea) (13140-81-3)

Conditions	Yield
Multi-step reaction with 2 steps 1: bromobenzene 2: bromobenzene View Scheme

benzidine dihydrochloride (531-85-1) → N,N'-biphenyl-4,4'-diyl-bis-carbamic acid diphenyl ester (148075-84-7)

Conditions	Yield
Multi-step reaction with 2 steps 1: bromobenzene 2: bromobenzene View Scheme

benzidine dihydrochloride (531-85-1) → N,N'-Di-(aminoxyacetyl)-benzidin

Conditions	Yield
Multi-step reaction with 2 steps 1: triethylamine / 1,4-dioxane 2: hydrogenchloride / ethyl acetate View Scheme

benzidine dihydrochloride (531-85-1) → 4,4'-Bis-phenylglyoxyloyl-diphenyl (47709-64-8)

Conditions	Yield
Multi-step reaction with 3 steps 1: (i) aq. HCl, NaNO2, (ii) /BRN= 4652394/, aq. CuCN 2: (i) Mg, (ii) /BRN= 1869917/, (iii) aq. HCl 3: SeO2, Ac2O View Scheme

benzidine dihydrochloride (531-85-1) → 4,4'-Bis-phenylacetyl-biphenyl (56794-20-8)

Conditions	Yield
Multi-step reaction with 2 steps 1: (i) aq. HCl, NaNO2, (ii) /BRN= 4652394/, aq. CuCN 2: (i) Mg, (ii) /BRN= 1869917/, (iii) aq. HCl View Scheme

fluorosilicic acid + benzidine dihydrochloride (531-85-1) → benzidine fluorosilicate

Conditions	Yield
In not given pptn. with H2SiF4 (D=1.30) from slightly hydrochloric soln. of benzidine hydrochloride at boiling temp.;;	>99
In not given pptn. with H2SiF4 (D=1.30) from slightly hydrochloric soln. of benzidine hydrochloride at boiling temp.;;	>99

benzidine dihydrochloride (531-85-1) + potassium hexacyanoferrate(III) → (benzidine)3H3{hexacyanoferrate(III)}*benzidine*2HCl

Conditions	Yield
In hydrogenchloride at -15°C; in diluted HCl;
In hydrogenchloride at -15°C; in diluted HCl;

tetracyanonickelate(II) (48042-08-6) + benzidine dihydrochloride (531-85-1) → C12H14N2(2+)*{Ni(CN)4}(2-)=C12H14N2{Ni(CN)4}

Conditions	Yield
In water pptn.;;
In water

benzidine dihydrochloride (531-85-1) + mercury dichloride → benzidinium tetrachloromercurate(II)

Conditions	Yield
In not given from hot soln. of calcd. amts. of educts; recrystn. from dild. HCl;

benzidine dihydrochloride (531-85-1) + palladium dichloride → dichloro benzidine palladium (II)

Conditions	Yield
In water on dropping of a small amt. of PdCl2 soln. to a boiling soln. of base chloride in 1l H2O, immediately forming of sparingly sol. ppte.;; on washing with hot H2O and drying at 100 °C; it is difficult to obtain pure compd. because of sparing solubility of chloride of base;;
In ethanol on react. of alc. benzidine soln. with PdCl2 soln.;;

hydrogenchloride (7647-01-0) + water (7732-18-5) + benzidine dihydrochloride (531-85-1) + cadmium(II) iodide → [benzidine(+2H)]3[CdI4]2Cl2*5H2O

Conditions	Yield
In hydrogenchloride mixt. of CdI2 and benzidine dichloride dissolved in H2O acidified by HCl; evapd. slowly; crystals isolated;

hydrogenchloride (7647-01-0) + benzidine dihydrochloride (531-85-1) + mercury(II) iodide → [benzidine(+2H)]4[Hg4I13]Cl3*2I2

Conditions	Yield
In hydrogenchloride mixt. of HgI2 and benzidine dichloride dissolved in H2O acidified by HCl; evapd. slowly; crystals isolated;

α,α′,δ,δ′-tetramethylcucurbit[6]uril (848440-56-2) + benzidine dihydrochloride (531-85-1) → C12H12N2*C40H44N24O12*2ClH

Conditions	Yield
In water

Upstream product

• 473-34-7 N,N-dichloro-p-toluenesulfonamide 
• 67-66-3 chloroform 
• 122-66-7 diphenyl hydrazine 
• 92-87-5 p,p'-diaminobiphenyl 

Downstream Products

• 2761-22-0 4.4'-Biphenylen-diisocyanat 
• 1591-30-6 (1,1'-biphenyl)-4,4'-dicarbonitrile 
• 120623-26-9 4,4'-Bis-(phenyl-trans-azo)-biphenyl 
• 13140-81-3 1,1'-(4,4'-biphenylene)bis(3-phenylurea) 
• 148075-84-7 N,N'-biphenyl-4,4'-diyl-bis-carbamic acid diphenyl ester 
• 56794-20-8 4,4'-Bis-phenylacetyl-biphenyl 

Relevant articles and documents

Exclusion complexes of the HCl salts of benzidine and bis(4-aminophenyl) methane with two methyl-substituted cucurbiturils

The interaction between two partially methyl-substituted cucurbiturils, a sym-tetramethyl-substituted cucurbit[6]uril (TMeQ[6]) and a meta-hexamethyl- substituted cucurbituril (m-HMeQ[6]), with the hydrochloride salt of benzidine (g1·HCl) and the analogue