Squaric acid
3,4-DIHYDROXY-3-CYCLOBUTENE-1,2-DIONE · 3,4-DIHYDROXYCYCLOBUT-3-ENE-1,2-DIONE · Squaric · 2-dione · NSC 624671 · squaricaci · SQUARC ACID · SQUARIC ACID
식별자 및 물리적 특성
| CAS No. | 2892-51-5 |
|---|---|
| 분자식 | C4H2O4 |
| 평균 분자량 | 114.06 g/mol |
| 단동위원소 질량 | 113.99530854 g/mol |
| SMILES | O=c1c(O)c(O)c1=O |
| InChIKey | PWEBUXCTKOWPCW-UHFFFAOYSA-N |
| PubChem CID | 17913 |
| ChEBI | CHEBI:52141 |
| EC No. | 220-761-4 |
| DTXSID | DTXSID9049409 |
화학 및 물리적 성질
| XLogP | -0.7 |
|---|---|
| 극성 표면적 | 74.6 |
| 수소 결합 공여자 수 | 2 |
| 수소 결합 수용자 수 | 4 |
| 회전 가능 결합 수 | 0 |
| 무거운 원자 수 | 8 |
| 형식 전하 | 0 |
| 복잡도 | 178 |
| Physical Description | Solid[Merck Index] Gray crystalline solid[Sigma-Aldrich MSDS] |
| 녹는점 | >300 °C(lit.) |
| 끓는 점 | 250.96°C |
| 밀도 | 1.82 g/cm3 |
| 굴절률 | 1.5800 (estimate) |
| 인화점 | 190 °C |
| 저장 조건 | Inert atmosphere,Room Temperature |
| 용해도 | 20g/L |
| 물리적 상태 | 결정성 분말 |
| pKa(산도 계수) | 1.5(at 25℃) |
| 색상 | 흰색에서 베이지색 |
| pH | 1 (1g/l, H2O, 20℃) |
| 용해도 | 20g/L(30℃) |
| Merck | 14,8769 |
| BRN | 774275 |
| InChI | 1S/C4H2O4/c5-1-2(6)4(8)3(1)7/h5-6H |
| InChIKey | PWEBUXCTKOWPCW-UHFFFAOYSA-N |
| SMILES | OC1=C(O)C(=O)C1=O |
| NIST | 3-Cyclobutene-1,2-dione, 3,4-dihydroxy-(2892-51-5) |
| EPA | 3-Cyclobutene-1,2-dione, 3,4-dihydroxy- (2892-51-5) |
화학적 성질
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.
안전 및 규제
| GHS 분류 | WarningH315 (72.1%): Causes skin irritation [Warning Skin corrosion/irritation]H317 (86.9%): May cause an allergic skin reaction [Warning Sensitization, Skin]H319 (72.1%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]H335 (70.5%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposureRespiratory tract irritation]P261, P264, P264+P265, P271, P272, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P333+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)Aggregated GHS information provided per 61 reports by companies from 9 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website. |
|---|---|
| 규제 정보 | 1,2-Dihydroxy-3,4-cyclobutenedione: Does not have an individual approval but may be used under an appropriate group standard |
| 유해성 요약 | A skin and strong eye irritantMay cause skin sensitization[Sigma-Aldrich MSDS] Search for (2892-51-5[EC/RN Number]) AND (dermatitis OR allergic OR sensitizer OR sensitization): no reports of skin sensitization[PubMed] |
| Hazard Classes and Categories | Skin Irrit. 2 (72.1%)Skin Sens. 1 (86.9%)Eye Irrit. 2 (72.1%)STOT SE 3 (70.5%)Skin Irrit. 2 (100%)Skin Sens. 1 (100%)Eye Irrit. 2 (100%)STOT SE 3 (100%) |
| 수질 위해 등급(WGK) | 3 |
| TSCA 등재 상태 | TSCA listed |
| RTECS 번호 | GU1800000 |
| 운송 번호(UN) | 3261 |
| 관세 코드 | 29144090 |
| 위험 문구(R) | 36/37/38-43 |
| 위험 표시 | Xi |
| 안전 문구(S) | 26-36-37/39 |
| 포장분류 | II |
| 위험 등급 | 8Eye Dam. 1Skin Corr. 1B |
| 위험 참고 사항 | Irritant |
| 저장 분류 | 8A - Combustible corrosive hazardous materials |
용도
용도
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
일반 설명
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.