Acetylenedicarboxylic acid

Molecule structure of Acetylenedicarboxylic acid (CAS NO.142-45-0): 

IUPAC Name: But-2-ynedioic acid 
Molecular Weight: 114.05628 g/mol
Molecular Formula: C₄H₂O₄ 
Density: 1.699 g/cm³ 
Melting Point: 180-187 °C (dec.)(lit.)
Boiling Point: 362.4 °C at 760 mmHg
Flash Point: 187.2 °C
Index of Refraction: 1.56
Molar Refractivity: 21.71 cm³
Molar Volume: 67.1 cm³
Surface Tension: 101.4 dyne/cm 
Enthalpy of Vaporization: 66.82 kJ/mol 
Vapour Pressure: 3.08E-06 mmHg at 25 °C 
Storage Temp.: 2-8 °C
Water Solubility: soluble
XLogP3-AA: 0.1
H-Bond Donor: 2
H-Bond Acceptor: 4
Exact Mass: 113.995309
MonoIsotopic Mass: 113.995309
Topological Polar Surface Area: 74.6
Heavy Atom Count: 8
Canonical SMILES: C(#CC(=O)O)C(=O)O
InChI: InChI=1S/C4H2O4/c5-3(6)1-2-4(7)8/h(H,5,6)(H,7,8)
InChIKey: YTIVTFGABIZHHX-UHFFFAOYSA-N
EINECS: 205-536-0
Product Categories: Pharmaceutical Intermediates; Aromatic Carboxylic Acids, Amides, Anilides, Anhydrides & Salts; Acetylenic Carboxylic Acids & Their Derivatives; Acetylenes

 Acetylenedicarboxylic acid was first described in 1877 by Polish chemist Ernest Bandrowski.

 Both Acetylenedicarboxylic acid (CAS NO.142-45-0) and the monobasic salt potassium hydrogenacetylenedicarboxylate KC₄HO₄ are commonly traded as laboratory chemicals. Acetylenedicarboxylic acid is an important laboratory reagent. It is also used in the synthesis of dimethyl acetylenedicarboxylate.

 Acetylenedicarboxylic acid can be made by treating α,β-dibromosuccinic acid with potassium hydroxide KOH in methanol or ethanol. This reaction yields potassium bromide and potassium acetylenedicarboxylate. The salts are separated and the latter is treated with sulfuric acid.

Hazard Codes: T, Xi
Risk Statements: 25-36/37/38 
R25 :Toxic if swallowed. 
R36/37/38:Irritating to eyes, respiratory system and skin.
Safety Statements: 26-45-37/39 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S45:In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) 
S37/39:Wear suitable gloves and eye/face protection.
RIDADR: UN 2811 6.1/PG 3
WGK Germany: 3
HazardClass: 6.1
PackingGroup: II
HS Code: 29171990

 Acetylenedicarboxylic acid (CAS NO.142-45-0) is also named as Butynedioic acid ; NSC 1903 ; NSC 631597 ; 2-Butynedioic acid ; Butynedioic acid . Acetylenedicarboxylic acid (CAS NO.142-45-0) is cream coloured to beige crystalline powder that soluble in ether.