2-Butyne-1,4-diol

Molecular structure of 2-Butyne-1,4-diol (CAS NO.110-65-6) is:

Product Name: 2-Butyne-1,4-diol
CAS Registry Number: 110-65-6
IUPAC Name: but-2-yne-1,4-diol
Molecular Weight: 86.08924 [g/mol]
Molecular Formula: C₄H₆O₂
XLogP3-AA: -1.1
H-Bond Donor: 2
H-Bond Acceptor: 2 
EINECS: 203-788-6
Melting Point: 54 °C 
Refractive index: 1.4804
Storage temp.: Refrigerator
Water Solubility: 3740 g/L (20 ºC)
Stability: Stable. Highly flammable solid. Incompatible with strong oxidizing agents, acid chlorides, acid anhydrides, strong acids, strong bases.  
Surface Tension: 60.086 dyne/cm
Density: 1.181 g/cm³
Flash Point: 135.558 °C
Enthalpy of Vaporization: 57.827 kJ/mol
Boiling Point: 260.202 °C at 760 mmHg
Vapour Pressure: 0.002 mmHg at 25°C
Product Categories: Pharmaceutical Intermediates;Acetylenes;Acetylenic Alcohols & Their Derivatives;Alkynes;Internal;Organic Building Blocks

 2-Butyne-1,4-diol (CAS NO.110-65-6) is a precursor to 1,4-butanediol.It can be used in the manufacture of plant protection agents, pesticides, textile additives, corrosion inhibitors, platicizers, synthetic resins, and polyurethanes.Also it is the major raw material of vitamin B6. And it is also used for brightening, preserving, and inhibiting nickel plating. 2-Butyne-1,4-diol (CAS NO.110-65-6) produced is consumed in the manufacture of butanediol and butenediol. It undergoes the usual reactions of primary alcohols that contribute to its use as a chemical intermediate. Because of its rigid, linear structure, many reactions forming cyclic products from butanediol or cis-butenediol give only polymers with butynediol. Both hydroxyl groups can be esterified normally, and the monoesters are readily prepared as mixtures with diesters and unesterified butynediol, but care must be taken in separating them because the monoesters disproportionate easily.
The hydroxyl groups can be alkylated with the alkylating agents, although a reverse treatment is used to obtain aryl ethers; for example; treatment of butynediol toluene sulfonate or dibromobutyne with a phenol gives the corresponding ether. Reactions of 2-Butyne-1,4-diol with alkylene oxides give ether alcohols.
In the presence of acid catalysts, 2-Butyne-1,4-diol and aldehydes or acetals give polymeric acetals, useful intermediates for acetylenic polyurethanes suitable for high-energy solid propellants.
HOCH₂C≡CCH₂OH → HO(CH₂C≡CCH₂OCH₂O)_nH
Electrolytic oxidation gives acetylene dicarboxylic acid (2-butyne-dioic acid) in good yields. It can be hydrogenated partway to butenediol (HOCH₂CH=CHCH₂OH) or completely to butanediol(HOCH₂CH₂CH₂CH₂OH).

 2-Butyne-1,4-diol (CAS NO.110-65-6) was first synthesized in 1906 by reaction of acetylene bis(magnesium bromide) with paraformaldehyde.
    HC≡CH + 2HCH=O → HOCH₂C≡CCH₂OH
All manufacturers of butynediol(110-65-6) use this formaldehyde ethynylation process, and yields of butynediol may be in excess of 90 percent, in addition to 4 to 5% propargyl alcohol.
          HC≡CH + HCH=O → HC≡CH₂OH

A poison by ingestion. A skin sensitizer upon long or repeated contact. Moderately explosive. When heated to decomposition it emits acrid smoke and fumes and may explode. Explosive reaction with traces of alkalies, alkali earth hydroxides, halide salts, strong acids, mercury salts + strong acids. See also ACETYLENE COMPOUNDS and ALKYNES.
Heating with strongly alkaline materials should be avoided.
Butynediol(110-65-6) is corrosive and irritates the skin and eyes. 
Hazard Codes: T,C
Risk Statements: 21-23/25-34-43-48/22 
R21:Harmful in contact with skin. 
R23/25:Toxic by inhalation and if swallowed. 
R34:Causes burns. 
R43:May cause sensitization by skin contact. 
R48/22:Harmful: danger of serious damage to health by prolonged exposure if swallowed.
Safety Statements: 25-26-36/37/39-45-46 
S25:Avoid contact with eyes. 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S36/37/39:Wear suitable protective clothing, gloves and eye/face protection. 
S45:In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) 
S46:If swallowed, seek medical advice immediately and show this container or label.
RIDADR: UN 2716 6.1/PG 3
WGK Germany: 2
RTECS: ES0525000
F: 23-10
HazardClass: 6.1
PackingGroup: III
HS Code: 29053980

 2-Butyne-1,4-diol , its cas register number is 110-65-6. It also can be called 1,4-Dihydroxy-2-butyne ; BOZ ; 2-Butyne-1,4-diol .It is a white to light-brown solid or brownish-yellow aqueous solution. Its solid sinks and mixes with water.And it is more difficult to polymerize than propargyl alcohol, but it cyclotrimerizes to hexamethylolbenzene (benzenehexamethanol) with a nickel carbonyl-phosphine catalyst or a rhodium chloride-arsine catalyst.