成盐
羧酸 → 羧酸盐：查看反应物、产物、反应条件与来源依据，探索相关转化和合成路径。
- 试剂
- 碱、碳酸盐或活泼金属
- 条件
- 室温
- 反应类别
- 酸碱反应
- 方程式
- RCO2H + NaOH -> RCO2Na + H2O
概览
羧酸与碱、碳酸盐及活泼金属反应，形成羧酸盐。
转化
- 方程式
- RCO2H + NaOH -> RCO2Na + H2O
- 试剂
- 碱、碳酸盐或活泼金属
- 反应环境
- 室温
- 反应类别
- 酸碱反应
- 机理
- proton transfer
- Evidence level
- 教材核心内容
参考步骤
Ethanoic-acid neutralisation and assay
Ethanoic acid + sodium hydroxide → sodium ethanoate + water
物料与用量
- Diluted ethanoic-acid sample or vinegar
- Standardised sodium hydroxide
- Suitable indicator such as phenolphthalein
仪器装置
- Burette
- Volumetric pipette
- Conical flask
实验步骤
- Titrate a known sample volume and obtain concordant readings.
- Calculate acid amount using the 1:1 mole ratio, then account for dilution.
后处理与分离
- The neutralised solution contains dissolved sodium ethanoate; this analysis does not isolate a pure dry salt.
关键控制条件
- The indicator endpoint should lie within the sharp pH change for a weak-acid/strong-base titration.
- Other titratable acids in vinegar would contribute to the result; an acid-equivalent concentration is not unique molecular identification.
实验技术
Acid–base titration
Use a known concentration and measured reacting volumes to determine acid or base content.
装置设置
- Rinse measuring apparatus appropriately, remove burette-tip bubbles and record initial and final readings.
- Approach the endpoint dropwise while mixing, then repeat to obtain concordant titres.
- Apply the balanced-equation mole ratio and any dilution factor.
操作检查
- Choose an endpoint within the steep part of the relevant titration curve.
- Concordant readings show repeatability; they do not remove concentration, calibration or endpoint bias.
底物范围
- 适用范围
- 羧酸与碱形成羧酸盐；与碳酸盐反应放出二氧化碳，与活泼金属反应放出氢气。
- 来源说明
- 显示的方程式以氢氧化钠为代表试剂；碳酸盐和金属反应的副产物不同。
相关反应
- Oxidation: Alcohols → Carboxylic acids
伯醇充分氧化生成羧酸。
- Complete oxidation: Primary alcohols → Carboxylic acids
伯醇充分氧化生成羧酸。
- Reduction: Carboxylic acids → Primary alcohols
羧酸还原生成伯醇。
- Oxidation: Aldehydes → Carboxylic acids
醛氧化生成羧酸。
- Hydrolysis: Nitriles → Carboxylic acids
腈可水解为羧酸；此处将原先合并的腈到酰胺路线拆分为单步官能团转化。
- Activation for amide formation: Carboxylic acids → Amide chemistry
羧酸或经活化的羧酸衍生物可用于形成酰胺键。
- Esterification: Carboxylic acids → Esters
羧酸与醇反应形成酯。
- Hydrolysis: Esters → Carboxylic acids
酯经水解重新生成羧酸产物。
- Chlorination: Carboxylic acids → Acyl chlorides
PCl5 将羧酸转化为酰氯。
- Chlorination with thionyl chloride: Carboxylic acids → Acyl chlorides
氯化亚砜将羧酸转化为酰氯，同时生成二氧化硫和氯化氢。
- Hydrolysis: Acyl chlorides → Carboxylic acids
水使酰氯水解为羧酸，同时释放氯化氢。
- Carboxylation: Grignard reagents → Carboxylic acids
格氏羧化经酸性后处理得到羧酸。
- Grignard carboxylation co reactant: Carbon dioxide → Carboxylic acids
二氧化碳与格氏试剂反应，经酸性后处理得到羧酸。
- Anhydride hydrolysis: Acid anhydrides → Carboxylic acids
水进攻酸酐羰基；四面体中间体消除时断开酰基与氧的连接。质子转移后生成羧酸；混合酸酐会产生两种不同的酸。
参考文献
- Pearson Edexcel Level 3 Advanced GCE in Chemistry specificationPearson Education Limited · Pearson qualifications · 2024
Supports the textbook-core organic reaction routes used for displayed route and mechanism content.
- Practical science: learning to investigateRoyal Society of Chemistry · RSC Education
Ethanoic-acid concentration in vinegar using sodium hydroxide and phenolphthalein; extension to quantitative titration.
- Titration: practical videos for 16–18 studentsRoyal Society of Chemistry · RSC Education
Accurate volumetric measurement, endpoints and concentration calculations.