p-toluenesulfonic acid is a strong organic acid with a pungent odor. It is used as a catalyst in various chemical reactions and as a reagent in organic synthesis.
| IUPAC Name | p-Toluenesulfonic acid |
| Molecular Formula | C7H8O3S |
| CAS Number | 104-15-4 |
| Synonyms | PTSA, 4-Methylbenzenesulfonic acid, p-Toluenesulphonic acid |
| InChI | InChI=1S/C7H8O3S/c1-6-2-4-7(5-3-6)11(8,9)10/h2-5H,1H3,(H,8,9,10) |
p-Toluenesulfonic Acid Properties
p-Toluenesulfonic Acid Formula
The formula of 4-methylbenzenesulfonic acid is C7H8O3S. It represents the molecular composition of the acid, consisting of seven carbon atoms, eight hydrogen atoms, three oxygen atoms, and one sulfur atom.
p-Toluenesulfonic Acid Molar Mass
The molar mass of 4-methylbenzenesulfonic acid is calculated to be approximately 172.2 grams per mole. Molar mass refers to the mass of one mole of a substance, which is determined by summing up the atomic masses of its constituent atoms.
p-Toluenesulfonic Acid Boiling Point
4-methylbenzenesulfonic acid has a boiling point of around 100-110 degrees Celsius. The boiling point represents the temperature at which the liquid form of a substance changes into a gas, with the vapor pressure equal to the atmospheric pressure.
p-Toluenesulfonic Acid Melting Point
The melting point of 4-methylbenzenesulfonic acid is typically around 105-107 degrees Celsius. The melting point indicates the temperature at which a solid substance transitions into a liquid state under normal atmospheric pressure.
p-Toluenesulfonic Acid Density g/mL
The density of 4-methylbenzenesulfonic acid is approximately 1.28 grams per milliliter (g/mL). Density refers to the mass of a substance per unit volume and is commonly expressed in grams per milliliter or grams per cubic centimeter.
p-Toluenesulfonic Acid Molecular Weight
The molecular weight of 4-methylbenzenesulfonic acid is approximately 172.2 grams per mole. It represents the sum of the atomic weights of all the atoms in the molecular formula of the acid, indicating its mass on a molecular scale.
p-Toluenesulfonic Acid Structure
4-methylbenzenesulfonic acid has a chemical structure consisting of a toluene ring with a sulfonic acid functional group (-SO3H) attached to the para position (p-) of the aromatic ring. This structure imparts acidity and influences its reactivity in chemical reactions.
p-Toluenesulfonic Acid Solubility
4-methylbenzenesulfonic acid is soluble in water and many organic solvents such as ethanol and acetone. Its solubility in water arises from the presence of the polar sulfonic acid group, which interacts with the polar water molecules through hydrogen bonding.
| Appearance | White to off-white crystalline powder |
| Specific Gravity | 1.28 g/mL |
| Color | Colorless to pale yellow |
| Odor | Pungent odor |
| Molar Mass | 172.2 g/mol |
| Density | 1.28 g/mL |
| Melting Point | 105-107 °C |
| Boiling Point | 100-110 °C |
| Flash Point | Not available |
| Water Solubility | Soluble |
| Solubility | Soluble in ethanol, acetone, and other organic solvents |
| Vapour Pressure | Not available |
| Vapour Density | Not available |
| pKa | ~ -2 |
| pH | < 1 |
p-Toluenesulfonic Acid Safety and Hazards
4-methylbenzenesulfonic acid poses certain safety concerns and hazards. It is corrosive to the skin, eyes, and respiratory system, causing irritation and burns upon contact. Inhalation of its vapors or dust can lead to respiratory discomfort. Protective measures, such as gloves and goggles, should be used when handling it. It should be stored in a tightly closed container, away from incompatible substances. In case of accidental ingestion or exposure, immediate medical attention is necessary. The acid should be handled in a well-ventilated area to avoid the build-up of hazardous vapors. Overall, proper precautions and adherence to safety guidelines are essential to minimize potential risks.
| Hazard Symbols | Corrosive |
| Safety Description | – Avoid contact with skin, eyes, and respiratory system. – Wear protective gloves, goggles, and clothing. – Store in a tightly closed container, away from incompatible substances. |
| Un IDs | Not available |
| HS Code | 29041000 |
| Hazard Class | 8 (Corrosive substance) |
| Packing Group | III (Minor danger) |
| Toxicity | Corrosive and irritant to skin and eyes. Inhalation of vapors or dust can cause respiratory discomfort. |
p-Toluenesulfonic Acid Synthesis Methods
Various methods allow the synthesis of 4-methylbenzenesulfonic acid. One common approach involves the reaction of toluene with concentrated sulfuric acid. The synthesis of p-toluenesulphonic acid involves maintaining a controlled temperature while adding toluene to sulfuric acid. The reaction produces p-toluenesulphonic acid as the primary product.
Another method involves the oxidation of p-toluenesulphonic acid precursor, p-toluenesulfonyl chloride, using an oxidizing agent such as potassium permanganate or sodium dichromate. The reaction takes place in an aqueous or organic solvent, resulting in the formation of p-toluenesulphonic acid.
To prepare p-toluenesulophnic acid, one can utilize fuming sulfuric acid (oleum) or sulfur trioxide to sulfonate toluene. This method involves the introduction of sulfuric acid or sulfur trioxide into toluene under controlled conditions, yielding p-toluenesulphonic acid.
A catalyst, such as a benzoyl peroxide or iron(III) chloride, is present during the reaction of toluene with sulfuric acid to synthesize p-toluenesulphonic acid. The catalyst facilitates the sulfonation process, leading to the formation of p-toluenesulphonic acid.
These synthesis methods enable the production of p-toluenesulphonic acid, which finds application in various industries, including pharmaceuticals, dyes, and organic synthesis. It is important to note that appropriate safety precautions and proper handling procedures should be followed during these synthetic processes.
p-Toluenesulfonic Acid Uses
4-methylbenzenesulfonic acid has numerous applications across various industries. Here are some of its common uses:
- Chemical Reactions: 4-methylbenzenesulfonic acid catalyzes esterification, acylation, and polymerization reactions.
- Organic Synthesis: Utilize 4-methylbenzenesulfonic acid as a reagent to introduce sulfonic acid functional groups into molecules, facilitating sulfonylation and desulfonation reactions in organic synthesis.
- Pharmaceuticals: Apply 4-methylbenzenesulfonic acid in synthesizing pharmaceutical intermediates, including antibiotics, analgesics, and anti-inflammatory drugs.
- Dye Production: Employ 4-methylbenzenesulfonic acid in manufacturing dyes and pigments by sulfonating aromatic compounds to produce colorants.
- Electroplating: Use 4-methylbenzenesulfonic acid as an acid catalyst in electroplating processes for depositing metal coatings on various surfaces.
- Ion Exchange Resins: Utilize 4-methylbenzenesulfonic acid in producing ion exchange resins used in water treatment, chromatography, and separation processes.
- Polymer Industry: Apply 4-methylbenzenesulfonic acid as a polymerization catalyst and stabilizer in the production of synthetic polymers and plastics.
- Surface Treatment: Employ 4-methylbenzenesulfonic acid in the surface treatment of metals, such as aluminum and steel, to enhance their corrosion resistance and adhesion properties.
- Cleaning Agents: Include 4-methylbenzenesulfonic acid as a component in cleaning agents and detergents to aid in removing mineral deposits and rust stains.
- Analytical Chemistry: Use 4-methylbenzenesulfonic acid as a standard substance for calibration purposes in various analytical techniques, such as high-performance liquid chromatography (HPLC).
These diverse applications highlight the versatility and significance of 4-methylbenzenesulfonic acid in various industrial processes and scientific fields.
Questions:
Q: How will ethanol and p-toluenesulfonic acid react with a carbonyl?
A: Ethanol and 4-methylbenzenesulfonic acid can undergo esterification with a carbonyl, resulting in the formation of an ester.
Q: What is p-toluenesulfonic acid used for?
A 4-methylbenzenesulfonic acid finds applications as a catalyst, reagent in organic synthesis, in dye production, pharmaceutical synthesis, and surface treatment of metals.
Q: Is pyridinium p-toluenesulfonate an acid?
A: Yes, pyridinium p-toluenesulfonate is an acid, specifically a sulfonic acid derivative of pyridine.
Q: Is p-toluenesulfonic acid inorganic?
A: No, 4-methylbenzenesulfonic acid is an organic compound containing carbon, hydrogen, oxygen, and sulfur atoms.
Q: What is the mechanism of p-toluenesulfonic acid and alcohol?
A: The mechanism involves the protonation of the alcohol by 4-methylbenzenesulfonic acid followed by the departure of a water molecule, resulting in the formation of an alkyl p-toluenesulfonate.
Q: Draw the organic product(s) of the following reaction: p-toluenesulfonic acid.
A: The organic product(s) depend on the specific reaction conditions and reactants involved, as 4-methylbenzenesulfonic acid can participate in various reactions.
Q: What is p-toluenesulfonic acid reactions?
A: 4-methylbenzenesulfonic acid can undergo reactions such as esterification, sulfonation, desulfonation, and substitution reactions with various organic compounds.
Q: Is p-toluenesulfonic acid an organic base?
A: No, 4-methylbenzenesulfonic acid is not an organic base but rather an organic acid due to the presence of a sulfonic acid group.
Q: How to make alkene with p-toluenesulfonic acid?
A: 4-methylbenzenesulfonic acid alone does not directly convert a compound into an alkene. However, it can be used as a catalyst or reagent in specific reactions that lead to alkene formation, such as dehydration or elimination reactions.