水杨酸
同一分子中酚羟基和羧基相邻，是阿司匹林化学中的重要化合物。
- 化学式
- C7H6O3
- 摩尔质量
- 138.12 g/mol
- Also known as
- 2-hydroxybenzoic acid, o-hydroxybenzoic acid, 2-Carboxyphenol, o-Carboxyphenol, Retarder W, Rutranex
概览
The two oxygen-containing groups provide distinct reaction sites. Acetylating the phenolic OH gives aspirin while retaining the carboxylic acid. Tracking which group reacts prevents confusion between aspirin formation and esterification of the carboxyl group to give methyl salicylate.
Identifiers
- 化学式
- C7H6O3
- 摩尔质量
- 138.12 g/mol
- Also known as
- 2-hydroxybenzoic acid, o-hydroxybenzoic acid, 2-Carboxyphenol, o-Carboxyphenol, Retarder W, Rutranex
化学标识符
- SMILES
- C1=CC=C(C(=C1)C(=O)O)O
- InChI
- InChI=1S/C7H6O3/c8-6-4-2-1-3-5(6)7(9)10/h1-4,8H,(H,9,10)
- PubChem CID
- 338
性质
- 熔点
- 159 °C
- 沸点
- 211 °C at 20 torr
- 密度
- 1.443 g/cu cm at 20 °C/4 °C
- 水中溶解度
- In water, 2,240 mg/L at 25 °C
Diagnostic tests
水杨酸与铁(III)的显色试验
- 试剂
- 参考检验方法中的铁(III)溶液
- 条件
- 在相同条件下，对比溶解的样品、水杨酸标准液和试剂空白。
- Positive observation
- 出现紫色配合物颜色。
- Negative observation
- 空白不呈现水杨酸盐配合物的紫色。
- Interpretation
- 游离的酚羟基可参与形成有色配合物。
- 适用范围
- 预期水杨酸呈阳性。
- 来源说明
- pH 和浓度会影响颜色；其他能配位的酚类可能干扰。
- 证据
- reference experiment
Related compounds
Connected reactions
- O acetylation: Salicylic acid → Aspirin
水杨酸的酚氧从乙酸酐获得乙酰基。酰基取代形成酯，同时保留独立的羧基；质子转移生成伴生产物乙酸。
- Acid hydrolysis: Aspirin → Salicylic acid
水进攻被酸活化的乙酰基羰基。酰基与氧的连接断裂并发生质子转移，恢复水杨酸的酚羟基；被移去的乙酰基形成乙酸。
- Alkaline hydrolysis and acidification: Methyl salicylate → Salicylic acid
氢氧根加成到酯羰基，置换甲氧基片段，后者形成甲醇。在碱性条件下，水杨酸盐基团处于去质子化状态；随后酸化可恢复中性羧酸和酚羟基。
参考文献
- PubChem Compound Summary: Salicylic acid (CID 338)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- The aspirin storyRoyal Society of Chemistry · RSC Education
Functional-group context for salicylic acid and aspirin; the catalog description is not clinical advice or a medicinal-product specification.
- OpenStax Organic Chemistry: Chemistry of estersJohn McMurry · OpenStax · 2023
Supports the qualitative structural interpretation of the recorded molecular structure; no new physical measurement or verified preparative yield is claimed.
- Hazardous Substances Data Bank (HSDB): Salicylic acid — melting pointHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/338#section=Melting-Point. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1438
- Hazardous Substances Data Bank (HSDB): Salicylic acid — boiling pointHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/338#section=Boiling-Point. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1438
- Hazardous Substances Data Bank (HSDB): Salicylic acid — densityHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/338#section=Density. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Lide, D.R. CRC Handbook of Chemistry and Physics 86TH Edition 2005-2006. CRC Press, Taylor & Francis, Boca Raton, FL 2005, p. 3-288
- Hazardous Substances Data Bank (HSDB): Salicylic acid — solubilityHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/338#section=Solubility. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Yalkowsky SH, Dannenfelser RM; The AQUASOL dATAbASE of Aqueous Solubility. Ver 5. Tucson, AZ: Univ AZ, College of Pharmacy (1992)
- Analysis of aspirin tablets on a microscaleRoyal Society of Chemistry · RSC Education
Source-supported qualitative reference observations.