550-74-3

Basic information

• Product Name: PICROLONIC ACID
• Synonyms: PICROLONIC ACID;2,4-dihydro-5-methyl-4-nitro-2-(4-nitrophenyl)-3h-pyrazol-3-on;2-Pyrazolin-5-one, 3-methyl-4-nitro-1-(p-nitrophenyl)-;3H-Pyrazol-3-one, 1,4-dihydro-5-methyl-4-nitro-2-(4-nitrophenyl)-;3-methyl-4-nitro-1-(p-nitrophenyl)-2-pyrazolin-5-on;3-Methyl-4-nitro-1-(p-nitrophenyl)-2-pyrazolin-5-one;5-Methyl-4-nitro-2-(4-nitrophenyl)-2,4-dihydro-3H-pyrazol-3-one;3-methyl-4-nitro-1-p-nitrophenyl-5-pyrazolone
• CAS NO: 550-74-3
• Molecular Formula: C10H8N4O5
• Molecular Weight: 264.19
• EINECS: 208-986-6
• Mol File: 550-74-3.mol
• Article Data: 0

Chemical Properties

• Melting Point: 119 °C
• Boiling Point: 548.8 °C at 760 mmHg
• Flash Point: 285.7 °C
• Appearance: beige to ochre-yellow powder
• Density: 1.65 g/cm³
• Vapor Pressure: 4.26E-12mmHg at 25°C
• Refractive Index: 1.714
• Storage Temp.: Refrigerator (+4°C)
• Solubility: 0.27 % in water at room temperature, readily soluble in alcohol.
• PKA: 2.44±0.40(Predicted)
• Water Solubility: Slightly soluble in water. Soluble in alcohol.
• Merck: 14,7412
• BRN: 623723
• CAS DataBase Reference: PICROLONIC ACID(CAS DataBase Reference)
• NIST Chemistry Reference: PICROLONIC ACID(550-74-3)
• EPA Substance Registry System: PICROLONIC ACID(550-74-3)

Safety Data

• Hazard Codes: Xn,Xi
• Statements: 68-36/37/38-22-36/38-7
• Safety Statements: 37/39-26-36
• RIDADR: 3224
• RTECS: UQ9510000
• TSCA: Yes
• Hazardous Substances Data: 550-74-3(Hazardous Substances Data)

Usage

Description

Picrolonic Acid, also known as picric acid, is an organic compound with the chemical formula C?H?(NO?)?OH. It is a beige to ochre-yellow powder that has been widely used as an analytical reagent in various applications due to its unique chemical properties.

Uses

Used in Chemical Analysis:
Picrolonic Acid is used as an analytical reagent for the detection and estimation of various elements, including alkaloids, tryptophan, phenylalanine, calcium, magnesium, lead, strontium, and thorium. Its ability to form practically insoluble complexes with calcium(II), lead(II), and thorium(IV) makes it particularly useful for the accurate determination of minute amounts of these metals.
Used in Spectrophotometric Determination:
Picrolonic Acid has also proved suitable for the spectrophotometric determination of calcium. When transformed by bromine water in an alkaline medium, it forms a red, water-soluble complex called calcium picrolonate. The absorption of this compound is constant for about two days and follows the Beer-Lambert Law, making it a reliable method for calcium analysis.
Used in the Isolation of Amines:
Picrolonic Acid serves as a reagent for the isolation of amines as crystalline π-complexes. This application is particularly useful in the field of organic chemistry, where the separation and identification of amines are crucial for various research and industrial processes.

Purification Methods

Crystallise picrolic acid from water or EtOH (solubility is 0.123% at 15o and 1.203% at 100o in H2O; and 1.107% at 0o and 11.68% at 81o in EtOH). It forms Ca, Cu Hg, Mg, Na, Sr, Pb and many other metal complexes [Maquestian et al Bull Soc Chim Belg 82 233 1973, Isaki et al. Chem Ber 74 1420 1941]. [Beilstein 24 H 51, 24 I 218, 24 II 25, 22 III/IV 105.]

InChI:InChI=1/C10H8N4O5/c1-6-9(14(18)19)10(15)12(11-6)7-2-4-8(5-3-7)13(16)17/h2-5,9H,1H3/t9-/m1/s1

Synthetic route

{(C6H5C6H5)2Cr}(1+)*OC6H5(1-)={(C6H5C6H5)2Cr}OC6H5 (33409-77-7) + picrolonic acid (550-74-3) → {(C6H5C6H5)2Cr}(1+)*C10H7N4O5(1-)={(C6H5C6H5)2Cr}C10H7N4O5

Conditions	Yield
	70%
	70%

methyl thioisocyanate (556-61-6) + picrolonic acid (550-74-3) + 2-(5-i.propil-4-imidazolilmetiltio)etilamina dibromidrato → N-metil-N'-<2-(5-i.propil-4-imidazolilmetiltio)etil>tiourea picrolonato

Conditions	Yield
1.) water, 8 h, r.t; 2.) ethanol, water; Yield given. Multistep reaction;

N-(2-methoxycarbonylhexa-2,4-dienyl)-N-methyldiphenylphosphinamide + picrolonic acid (550-74-3) → 1,2-dimethyl-5-methoxycarbonyl-1,2,3,6-tetrahydropyridinium picrolonate

Conditions	Yield
Yield given. Multistep reaction;

(+/-)-8-benzyloxy-3α-ethyl-1,3,4,6,7,11bα-hexahydro-9,10-dimethoxy-2H-benzoquinolizine-2β-acetic acid (61194-41-0, 65942-18-9) + picrolonic acid (550-74-3) → (+/-)-7 picrolonate

Conditions	Yield
In ethanol

picrolonic acid (550-74-3) + strontium chloride → picrolonic acid, strontium salt * 7 H2O

Conditions	Yield
In sodium hydroxide satd. pyrazolone acid; pH=7; 0.033 n Sr soln.; equimolar;; pptn.;;

barium(II) + picrolonic acid (550-74-3) → barium picrolonate

Conditions	Yield
In water addition of a satd. picolonic acid-solution to a neutral or weak acidic Ba-salt-solution forms Ba(C10H7O5N4)2;;
In water

silver nitrate + picrolonic acid (550-74-3) → Ag(3-methyl-4-nitro-1-(4-nitro-phenyl)-5-pyrazolone)NO3

Conditions	Yield
In water
In water

manganese(II) chloride tetrahydrate + picrolonic acid (550-74-3) → Mn(2+)*2C10H7N4O5(1-)*2.5H2O=Mn(C10H7N4O5)2*2.5H2O

Conditions	Yield
In water with twofold excess of picrolonic acid; heated to boiling; ppt. washed with water and ethanol, then ether and dried at 100°C in vac.;
In water

{(C6H5C6H5)2Cr}(1+)*OC6H5(1-)={(C6H5C6H5)2Cr}OC6H5 (33409-77-7) + picrolonic acid (550-74-3) → {(C6H5C6H5)2Cr}(1+)*C10H7N4O5(1-)={(C6H5C6H5)2Cr}C10H7N4O5

Conditions	Yield
	70%
	70%

methyl thioisocyanate (556-61-6) + picrolonic acid (550-74-3) + 2-(5-i.propil-4-imidazolilmetiltio)etilamina dibromidrato → N-metil-N'-<2-(5-i.propil-4-imidazolilmetiltio)etil>tiourea picrolonato

Conditions	Yield
1.) water, 8 h, r.t; 2.) ethanol, water; Yield given. Multistep reaction;

N-(2-methoxycarbonylhexa-2,4-dienyl)-N-methyldiphenylphosphinamide + picrolonic acid (550-74-3) → 1,2-dimethyl-5-methoxycarbonyl-1,2,3,6-tetrahydropyridinium picrolonate

Conditions	Yield
Yield given. Multistep reaction;

(+/-)-8-benzyloxy-3α-ethyl-1,3,4,6,7,11bα-hexahydro-9,10-dimethoxy-2H-benzoquinolizine-2β-acetic acid (61194-41-0, 65942-18-9) + picrolonic acid (550-74-3) → (+/-)-7 picrolonate

Conditions	Yield
In ethanol

picrolonic acid (550-74-3) + strontium chloride → picrolonic acid, strontium salt * 7 H2O

Conditions	Yield
In sodium hydroxide satd. pyrazolone acid; pH=7; 0.033 n Sr soln.; equimolar;; pptn.;;

barium(II) + picrolonic acid (550-74-3) → barium picrolonate

Conditions	Yield
In water addition of a satd. picolonic acid-solution to a neutral or weak acidic Ba-salt-solution forms Ba(C10H7O5N4)2;;
In water

silver nitrate + picrolonic acid (550-74-3) → Ag(3-methyl-4-nitro-1-(4-nitro-phenyl)-5-pyrazolone)NO3

Conditions	Yield
In water
In water

manganese(II) chloride tetrahydrate + picrolonic acid (550-74-3) → Mn(2+)*2C10H7N4O5(1-)*2.5H2O=Mn(C10H7N4O5)2*2.5H2O

Conditions	Yield
In water with twofold excess of picrolonic acid; heated to boiling; ppt. washed with water and ethanol, then ether and dried at 100°C in vac.;
In water