ChemicalBook > CAS DataBase List > Squaric acid

Squaric acid

Product Name
Squaric acid
CAS No.
2892-51-5
Chemical Name
Squaric acid
Synonyms
3,4-DIHYDROXYCYCLOBUT-3-ENE-1,2-DIONE;3,4-DIHYDROXY-3-CYCLOBUTENE-1,2-DIONE;Squaric;2-dione;NSC 624671;squaricaci;SQUARC ACID;SQUARIC ACID;QUADRATIC ACID;obutene-1,2-dione
CBNumber
CB6263069
Molecular Formula
C4H2O4
Formula Weight
114.06
MOL File
2892-51-5.mol
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Squaric acid Property

Melting point:
>300 °C(lit.)
Boiling point:
250.96°C
Density 
1.82 g/cm3
refractive index 
1.5800 (estimate)
Flash point:
190 °C
storage temp. 
Inert atmosphere,Room Temperature
solubility 
20g/l
pka
1.5??(at 25℃)
form 
Crystalline Powder
color 
White to beige
PH
1 (1g/l, H2O, 20℃)
Water Solubility 
20 g/L (30 ºC)
Merck 
14,8769
BRN 
774275
InChIKey
PWEBUXCTKOWPCW-UHFFFAOYSA-N
CAS DataBase Reference
2892-51-5(CAS DataBase Reference)
NIST Chemistry Reference
3-Cyclobutene-1,2-dione, 3,4-dihydroxy-(2892-51-5)
EPA Substance Registry System
3-Cyclobutene-1,2-dione, 3,4-dihydroxy- (2892-51-5)
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Safety

Hazard Codes 
Xi
Risk Statements 
36/37/38-43
Safety Statements 
26-36-37/39
RIDADR 
3261
WGK Germany 
3
RTECS 
GU1800000
Hazard Note 
Irritant
TSCA 
Yes
HazardClass 
8
PackingGroup 
II
HS Code 
29144090
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Hazard and Precautionary Statements (GHS)

Symbol(GHS)
Signal word
Danger
Hazard statements

H314Causes severe skin burns and eye damage

Precautionary statements

P260Do not breathe dust/fume/gas/mist/vapours/spray.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P301+P330+P331IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.

P303+P361+P353IF ON SKIN (or hair): Remove/Take off Immediately all contaminated clothing. Rinse SKIN with water/shower.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

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N-Bromosuccinimide Price

Sigma-Aldrich
Product number
123447
Product name
3,4-Dihydroxy-3-cyclobutene-1,2-dione
Purity
99%
Packaging
5g
Price
$65.2
Updated
2024/03/01
Sigma-Aldrich
Product number
123447
Product name
3,4-Dihydroxy-3-cyclobutene-1,2-dione
Purity
99%
Packaging
25g
Price
$202
Updated
2024/03/01
TCI Chemical
Product number
D1399
Product name
3,4-Dihydroxy-3-cyclobutene-1,2-dione
Purity
>98.0%(HPLC)(T)
Packaging
5g
Price
$60
Updated
2024/03/01
TCI Chemical
Product number
D1399
Product name
3,4-Dihydroxy-3-cyclobutene-1,2-dione
Purity
>98.0%(HPLC)(T)
Packaging
25g
Price
$177
Updated
2024/03/01
Alfa Aesar
Product number
A15169
Product name
3,4-Dihydroxy-3-cyclobutene-1,2-dione, 98+%
Packaging
1g
Price
$22.65
Updated
2024/03/01
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Squaric acid Chemical Properties,Usage,Production

Chemical Properties

Squaric acid (3,4-dihydroxycyclobut-3-ene-1,2-dione), also known as quadratic acid, has the fascinating structure, and is a vinylogous carboxylic acid. The parent compound is a white,crystalline powder which melts at~300℃. It is highly acidic (pKa 1.5 for the first proton and 3.4 for the second) due to resonance stabilization of the anion and exhibits IR resonances indicative of strong hydrogen bonding [2326cm-1 (OH),1818 cm-1 (C=O), and 1639cm-1 (C=C)].The UV absorption spectrum suggests that the acid is essentially completely ionized. Squaric acid is freely soluble in water but has poor solubility in many organic solvents.Solutions give an intense purple color with iron(III) chloride, and are also known to decolorize bromine water, cerium(IV) nitrate, and permanganate solutions.As the carbonyl groups are similar to those of carboxylic acids rather than those of ketones, squaric acid does not react in the phenylhydrazine test.The squarate dianion is thought to be completely symmetrical (unlike squaric acid itself), with all C-C and C-O bond lengths being, respectively, identical, as the negative charges are equally distributed between allthe oxygen atoms.The IR spectrum of dipotassium squarate (dipotassium 3,4-dioxocy-clobut-1-ene-1,2-diolate) differs greatly from that of squaric acid, with the loss of the car-bonyl (C=O) and alkene(C=C) absorptions seen in the protonated form, and supportsthe proposed symmetrical structure.

Uses

Squaric acid used as intermediate for squaraine dyes and heterocycles. Squaric acid is an immunotherapy used to treat common warts. This treatment is non-toxic, and easy to use. The treatment activated your immune system to combat the warts and therefore it may cause an allergic reaction , similar to poison oak. This reaction can be managed with a topical cortisone cream. Blistering and lightening of the skin may occur, but rarely.
Squaric acid derivatives – synthetic targets for ring expansion reactions

Uses

3,4-Dihydroxy-3-cyclobutene-1,2-dione is used to produce diethoxy-cyclobutenedione by heating, pharmaceutical intermediates, squarylium dyes, and photoconducting squaraines; The dibutylester is used as a contact sensitizer in the treatment of alopecia and warts.

Uses

3,4-Dihydroxy-3-cyclobutene-1,2-dione can be used:

  • In fluorescence detection in immunoassays, hybridization assays, enzymatic reactions, and other analytical procedures.
  • To form diffraction quality crystals.
  • To synthesize a squarate dianion, which is used as a building block to create uncharged polymeric networks. These ordered structures are used in catalysis, nonlinear optics, electrical conductivity, molecular recognition, and molecular sieves.

Definition

ChEBI: A carbon oxoacid that consists of 1,2-diketocyclobut-3-ene bearing two enolic hydroxy substituents at positions 3 and 4.

Synthesis Reference(s)

Journal of the American Chemical Society, 88, p. 1533, 1966 DOI: 10.1021/ja00959a040
Tetrahedron Letters, 18, p. 4437, 1977

General Description

3,4-dihydroxy-3-cyclobutene-1,2 dione, commonly known as squaric acid, is widely used in bioorganic and medicinal chemistry. It is an inhibitor of glyoxylase, semiqauric acid, pyruvate dehrogenase, and transketolase. It is used as a replacement for phosphate in a peptide-based ligand for an SH2 domain. Its derivatives are high-affinity ligands for excitatory amino acid receptors. These derivatives are also used as dyes for fluorescence detection of small biological molecules.

Biotechnological Applications

squaric acid is widely used in bioorganic and medicinal chemistry. It is an inhibitor of glyoxylase, semiqauric acid, pyruvate dehrogenase, and transketolase. It is used as a replacement for phosphate in a peptide-based ligand for an SH2 domain. Its derivatives are high-affinity ligands for excitatory amino acid receptors. These derivatives are also used as dyes for fluorescence detection of small biological molecules.
squaric acid can be used:
In fluorescence detection in immunoassays, hybridization assays, enzymatic reactions, and other analytical procedures.
To form diffraction quality crystals.
To synthesize a squarate dianion, which is used as a building block to create uncharged polymeric networks. These ordered structures are used in catalysis, nonlinear optics, electrical conductivity, molecular recognition, and molecular sieves.

Purification Methods

Purify squaric acid by recrystallisation from H2O — this is quite simple because the acid is ~ 7% soluble in boiling H2O and only 2% at room temperature. It is not soluble in Me2CO or Et2O; hence it can be rinsed with these solvents and dried in air or a vacuum. It is not hygroscopic and gives an intense purple colour with FeCl3. It has IR max at 1820 (C=O) and 1640 (C=C) cm-1, and UV max at 269.5nm ( 37K M-1cm -1). [Cohn et al. J Am Chem Soc 81 3480 1959, Park et al. J Am Chem Soc 84 2919 1962] See also pKa values of 0.59 ±0.09 and 3.48 ±0.023 [Scwartz & Howard J Phys Chem 74 4374 1970]. [Schmidt & Reid Synthesis 869 1978, Beilstein 8 IV 2701.]

Squaric acid Preparation Products And Raw materials

Raw materials

Preparation Products

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View Lastest Price from Squaric acid manufacturers

Hebei Zhuanglai Chemical Trading Co.,Ltd
Product
Squaric acid 2892-51-5
Price
US $80.00/kg
Min. Order
1kg
Purity
99
Supply Ability
5000
Release date
2024-04-28
SHANDONG OUCHEM CO.,LTD.
Product
3,4-DIHYDROXY-3-CYCLOBUTEN-1,2-DIONE 2892-51-5
Price
US $0.00-0.00/KG
Min. Order
1KG
Purity
98% Min.
Supply Ability
1000KG
Release date
2024-01-17
Hebei Weibang Biotechnology Co., Ltd
Product
Squaric acid 2892-51-5
Price
US $0.00/KG
Min. Order
1KG
Purity
99%
Supply Ability
500000kg
Release date
2024-10-28

2892-51-5, Squaric acidRelated Search:

Diethyl squarate Stearic acid Maleic acid Glycine Fumaric acid Folic acid Ethyl 2-(Chlorosulfonyl)acetate Fumaronitrile CIS-BUTENEDIOIC ANHYDRIDE 4'-Hydroxyacetophenone Fenofibric acid L(+)-Diethyl L-tartrate Perfluoro-2-methyl-2-pentene Methyl vinyl ketone 3,4-Dimethoxy-3-cyclobutene-1,2-dione 3,4-Diisopropoxy-3-cyclobutene-1,2-dione Dibutyl squarate 3,4-DIHYDROXY-3-CYCLOBUTENE-1,2-DIONE, DILITHIUM SALT, 98,3,4-DIHYDROXY-3-CYCLOBUTENE-1,2-DIONE, D ILITHIUM SALT, 98%

  • dihydroxy-cyclobutenedion
  • dihydroxycyclobutenedione
  • 3,4-DIHYDROXY-3-CYCLOBUTEN-1,2-DIONE
  • 3,4-DIHYDROXY-3-CYCLOBUTENE-1,2-DIONE
  • 3,4-DIHYDROXYCYCLOBUT-3-ENE-1,2-DIONE
  • 1-Cyclobutene-3,4-dione-1,2-diol Squaric Acid
  • 1,2-DIHYDROXY-3,4-CYCLOBUTENEDIONE FOR S
  • NSC 624671
  • dihydroxycyclobut-3-ene-1,2-dione
  • Squaric acid, 1,2-Dihydroxy-3,4-dioxocyclobut-1-ene
  • 3,4-Dihydroxy-3-cyclobutene-1,2-dione 99%
  • 3,4-Dihydroxy-3-cyclobutene-1,2-dione 3,4-Dihydroxycyclobut-3-ene-1,2-dione
  • 1-Cyclobutene-3,4-dione-1,2-diol 3,4-Dihydroxy-3-cyclobutene-1,2-dione
  • 1,2-Dihydroxy-3,4-cyclobutenedione for synthesis
  • 1,2-Dihydroxycyclobutene-3,4-dione
  • 1,2-Diketo-3,4-dihydroxycyclobutene
  • 3,4-dihydroxy-3-cyclobutene-2-dione
  • 3,4-Dihydroxy-cyclobutene-1,2-dione
  • 3,4-dihydroxy-cyclobutene-2-dione
  • 3-Cyclobutene-1,2-dione,3,4-dihydroxy-
  • Cyclobutene-1,2-dione, 3,4-dihydroxy-
  • Cyclobutenedione, dihydroxy-
  • 1,2-DIHYDROXY-1-CYCLOBUTEN-3,4-DI
  • 1,2-DIHYDROXY-1-CYCLOBUTEN-3,4-DIONE
  • 1,2-DIHYDROXY-3,4-CYCLOBUTENEDIONE
  • 1,2-DIHYDROXY CYCLOBUTENEDIONE
  • 1-CYCLOBUTENE-3,4-DIONE-1,2-DIOL
  • QUADRATIC ACID
  • SQUARIC ACID
  • DIKETOCYCLOBUTENEDIOL
  • TIMTEC-BB SBB007891
  • 3,4-DIHYDROXY-3-CYCLOBUTENE-1,2-DIONE, 9 9%
  • 3,4-Dihdroxy-3-Cyclobutene-1,2-Dione
  • 3,4-DIHYDROXY-3-CYCLOBUTENE-1,2-DIONE(SQUARIC ACID)
  • Squaric
  • SQUARC ACID
  • SQUARIC ACID (3,4-DIHYDROXY-3-CYCLOBUTENE-1,2-DIONE)
  • 3,4-Dihydroxy-3-cyclobutan-1,2-dione
  • SQUARICACIDDIBUTYLESTERS
  • 3,4-Dihydroxy-3-cyclobutene-1,2-dione, 98+%
  • 2-dione
  • 4-dihydroxy-3-cyclobutene-1
  • 3,4-Dihydroxy-3-cyclobuten-1,2-dion
  • 3,4-Dihydroxy-3-cyclobutene-1,2-dione, 99% 25GR
  • 3,4-Dihydroxy-3-cyclobutene-1,2-dione, 99% 5GR
  • 3,4-Dihydroxy-3-cycL
  • obutene-1,2-dione
  • 3,4-Dihydroxy-3-cyclobutene-1,2-dione, 99%, for synthesis
  • 3,4-Dihydroxy-3-cyclobutene-1,2-dione &gt
  • squaricaci
  • 2892-51-5 3,4-Dihydroxy-3-cyclobutene-1,2-dione
  • 2892-51-5
  • 2892-51-4
  • 2832-51-5
  • HO2C4O2
  • C4H2O4
  • Organic Building Blocks
  • Ketones