Isobutanol

Product Details

CasNo： 78-83-1

MF： C₄H₁₀O

Appearance： liquid

Purity： 99.5% Min

1. Basic Information​

1. Synonyms: 2 - Methyl - 1 - propanol; Isopropylcarbinol; Isobutyl alcohol​

1. Molecular Formula: C₄H₁₀O​

1. Molecular Weight: 74.12 g/mol​

1. CAS Number: 78 - 83 - 1​

1. EINECS Number: 201 - 148 - 0​

2. Physicochemical Properties​

2.1 Physical Properties​

• Appearance: Colorless, transparent liquid​

• Odor: Characteristic, somewhat sweet and alcoholic odor​

• Melting Point: - 108 °C​

• Boiling Point: 107.9 °C​

• Relative Density (Water = 1): 0.802 at 20 °C​

• Relative Vapor Density (Air = 1): 2.55​

• Saturated Vapor Pressure: 1.33 kPa at 21.7 °C​

• Flash Point: 25 °C (closed - cup)​

• Auto - ignition Temperature: 415 °C​

• Explosive Limits in Air: Lower explosive limit (LEL) 1.7% (by volume); Upper explosive limit (UEL) 10.6% (by volume)​

• Solubility: Slightly soluble in water (about 9.5 g/100 mL at 20 °C), miscible with many organic solvents such as ethanol, ether, benzene, ethyl acetate, chloroform, and acetone​

• Refractive Index: 1.396 at 20 °C​

• Viscosity: 2.43 mPa·s at 20 °C​

• Heat of Vaporization: 43.1 kJ/mol​

• Heat of Combustion: - 2667.7 kJ/mol​

• Critical Temperature: 265 °C​

• Critical Pressure: 4.86 MPa​

• Octanol/Water Partition Coefficient (log P): 0.65 - 0.83​

2.2 Chemical Properties​

Isobutanol is a primary alcohol, and it exhibits typical alcohol - like chemical reactions.​

• Combustion: It burns readily in air, producing carbon dioxide and water. The combustion reaction can be represented by the equation: 2C₄H₁₀O + 13O₂ → 8CO₂ + 10H₂O​

• Oxidation: Can be oxidized to isobutyraldehyde or isobutyric acid. For example, in the presence of a suitable oxidizing agent like potassium dichromate in acidic solution, it can be oxidized step - by - step.​

• Esterification: Reacts with carboxylic acids to form esters. For instance, with acetic acid in the presence of an acid catalyst, it forms isobutyl acetate: C₄H₁₀O + CH₃COOH ⇌ CH₃COOC₄H₉ + H₂O​

• Dehydration: Under the influence of strong acids (such as sulfuric acid) and high temperatures, it can undergo dehydration to form isobutene. The reaction is an elimination reaction: C₄H₁₀O → C₄H₈ + H₂O​

3. Production Methods​

3.1 From Propylene Oxo - Synthesis (Industrial Main Method)​

• Propylene and synthesis gas (a mixture of carbon monoxide and hydrogen) are used as raw materials.​

• In the oxo - synthesis process, under the action of a catalyst (such as a cobalt - based or rhodium - based catalyst), propylene reacts with synthesis gas to form a mixture of n - butyraldehyde and isobutyraldehyde.​

• The reaction conditions are typically at a certain temperature (around 100 - 180 °C) and pressure (several to tens of MPa).​

• After the reaction, the catalyst is removed, and then the aldehyde mixture is hydrogenated. The hydrogenation reaction is usually carried out in the presence of a hydrogenation catalyst (such as nickel - based catalyst) at appropriate temperature and pressure. Through this hydrogenation step, n - butyraldehyde is converted to n - butanol, and isobutyraldehyde is converted to isobutanol. Finally, the products are separated by distillation and other separation techniques to obtain pure isobutanol. The chemical reactions involved are as follows:​

• Propylene oxo - synthesis: CH₃CH = CH₂+CO + H₂ → CH₃CH₂CH₂CHO (n - butyraldehyde)+(CH₃)₂CHCHO (isobutyraldehyde)​

• Hydrogenation of isobutyraldehyde: (CH₃)₂CHCHO + H₂ → (CH₃)₂CHCH₂OH (isobutanol)​

3.2 Hydrogenation of Isobutyraldehyde​

• Isobutyraldehyde can be directly hydrogenated to produce isobutanol.​

• The reaction is usually carried out in the liquid - phase. Nickel - based catalysts are commonly used for this hydrogenation reaction.​

• The reaction conditions include a certain temperature (e.g., 80 - 150 °C) and pressure (e.g., 2 - 5 MPa). The high - pressure hydrogen gas is introduced into the reaction system containing isobutyraldehyde and the catalyst, and isobutyraldehyde is reduced to isobutanol. The reaction equation is: (CH₃)₂CHCHO + H₂ → (CH₃)₂CHCH₂OH​

3.3 Recovery from By - products of Methanol Synthesis​

• In the production of methanol, a by - product called isobutyl oil is generated.​

• Isobutyl oil contains isobutanol and other components.​

• First, isobutyl oil is subjected to a process to remove methanol. Then, it is treated with a salting - out agent to separate water.​

• After that, azeotropic distillation is carried out. Through a series of distillation operations, isobutanol is separated and purified from the other components in isobutyl oil to obtain the final isobutanol product.​

3.4 Fermentation Method (Less Common Industrially)​

• In nature, isobutanol can be produced by the natural fermentation of carbohydrates by certain microorganisms, such as some strains of bacteria or yeast.​

• Industrially, efforts have been made to use genetically modified microorganisms to produce isobutanol through fermentation processes. For example, through metabolic engineering of microorganisms like Escherichia coli or Saccharomyces cerevisiae, the metabolic pathways can be modified to direct the conversion of sugars (such as glucose) into isobutanol. However, compared with the chemical synthesis methods, the fermentation method currently has some challenges in terms of production efficiency and cost, so it is not as widely used in large - scale industrial production. The general fermentation reaction can be simply represented as: Carbohydrates + Microorganisms → Isobutanol + Other by - products​

4. Main Applications​

4.1 Solvent Applications​

• Paint and Coating Industry:​

• Isobutanol is an excellent solvent for various coatings. It can dissolve many resins, such as nitrocellulose, ethyl cellulose, and some alkyd resins. In the production of nitrocellulose lacquers, it helps to dissolve the nitrocellulose and other components, ensuring good film - forming properties. It can also adjust the drying rate of the paint. For example, when added to air - drying paints, it can slow down the drying process slightly, allowing for better leveling and smoothness of the paint film. In addition, it is used in the formulation of water - reducible coatings as a cosolvent to improve the solubility and stability of the resin - water system.​

• In the production of inks, especially for some high - quality printing inks, isobutanol is used as a solvent. It can dissolve the colorants (such as pigments and dyes) and resins in the ink, ensuring good flowability and transferability during the printing process. It also helps to control the drying time of the ink on the printing substrate, which is crucial for achieving clear and sharp prints.​

• It is also used as a solvent in the production of adhesives. For example, in some solvent - based adhesives, isobutanol can dissolve the polymer components, making the adhesive easier to apply and ensuring good adhesion between different materials.​

• Extraction Solvent:​

• In the food and beverage industry, isobutanol is used as an extraction solvent. It can be used to extract flavors and fragrances from natural sources. For example, it can be used to extract essential oils from plants. It is also used in the extraction of some food additives or active ingredients from food raw materials. In addition, it is used in the separation of certain substances in the laboratory. For instance, it can be used to separate some metal salts from their mixtures, such as separating lithium salts from mixtures with other salts.​

• In the pharmaceutical industry, it can be used as an extraction solvent for extracting active pharmaceutical ingredients from natural or synthetic sources. It can also be used in the purification process of drugs to remove impurities.​

4.2 Organic Synthesis Raw Material​

• Ester Synthesis:​

• Isobutanol is widely used in the synthesis of esters. One of the most common esters is isobutyl acetate. Isobutyl acetate has a pleasant fruity odor and is widely used as a solvent in the paint, ink, and perfume industries. It is also used as a flavoring agent in the food industry. The synthesis of isobutyl acetate from isobutanol and acetic acid is an important industrial process.​

• It is also used to synthesize other esters such as isobutyl acrylate. Isobutyl acrylate is an important monomer for the production of polymers, which are used in coatings, adhesives, and plastics. The polymerization of isobutyl acrylate can form polymers with good film - forming properties, flexibility, and adhesion.​

• Synthesis of Other Organic Compounds:​

• In the production of pesticides, isobutanol is used to synthesize some important intermediates. For example, it is used in the synthesis of isobutyronitrile, which is an intermediate for the production of the pesticide diazinon.​

• In the manufacture of petroleum additives, isobutanol can be used to synthesize compounds that improve the performance of fuels. For example, some detergents and dispersants used in gasoline and diesel fuels are synthesized using isobutanol as a starting material. These additives can help to clean the engine, prevent the formation of deposits, and improve the combustion efficiency of the fuel.​

• It is also used in the synthesis of antioxidants. For example, 2,6 - di - tert - butyl - p - cresol (BHT), an important antioxidant used in the food, rubber, and plastics industries, can be synthesized using isobutanol as a raw material. BHT can prevent the oxidation of fats, oils, and polymers, thus extending their shelf life.​

4.3 Food and Flavor Industry​

• Isobutanol is approved as a flavoring agent in many countries. It has a characteristic odor and can be used to enhance the flavor of food products. It is used in the formulation of artificial flavors for soft drinks, candies, baked goods, and dairy products. The addition of isobutanol in appropriate amounts can provide a unique flavor note, similar to a light, sweet - alcoholic aroma, which can improve the overall flavor profile of the food product. However, the use level is strictly regulated to ensure food safety.​

4.4 Fuel and Energy - Related Applications​

• Fuel Additive:​

• Isobutanol can be used as a fuel additive. It has a higher energy density compared to ethanol. When added to gasoline, it can improve the octane rating of the fuel, which helps to prevent engine knocking. It also has better solubility in gasoline compared to ethanol and can be blended in higher concentrations without causing phase separation. In addition, isobutanol - blended fuels can reduce the emissions of some pollutants, such as particulate matter and carbon monoxide, to a certain extent.​

• Biofuel Potential:​

• There is growing interest in using isobutanol as a biofuel. It can be produced from renewable resources through fermentation processes using genetically engineered microorganisms. As a biofuel, isobutanol has several advantages over traditional biofuels like ethanol. It has a higher energy content, lower volatility, and better cold - start properties. It can be used in existing internal combustion engines with minimal or no modification, which makes it a promising alternative to fossil - based fuels in the future.​

4.5 Other Applications​

• In the textile industry, it can be used in the finishing process of fabrics. It can help to dissolve some finishing agents and improve the penetration and adhesion of these agents on the fabric surface, thereby improving the properties of the fabric, such as softness, wrinkle - resistance, and color fastness.​

• In the electronics industry, isobutanol can be used as a cleaning agent for electronic components. Its good solvent properties can effectively remove oils, greases, and other contaminants from the surface of electronic components without leaving residues that could affect the performance of the components.​

5. Packaging and Storage​

5.1 Packaging​

• Drums: Isobutanol is commonly packaged in 165 - 170 kg galvanized iron drums. These drums are designed to be leak - proof and can withstand the transportation and storage conditions. The drums are usually equipped with tight - fitting lids to prevent evaporation and leakage of isobutanol.​

• IBC Totes: Intermediate Bulk Containers (IBC totes) are also used for packaging isobutanol, especially for larger - volume shipments. IBC totes can hold up to 1000 liters of isobutanol. They are made of high - density polyethylene (HDPE) or other suitable materials that are resistant to the corrosive effects of isobutanol. IBC totes are equipped with valves and fittings for easy filling and discharging.​

• Tank Trucks and Rail Tank Cars: For large - scale transportation, isobutanol can be transported in tank trucks or rail tank cars. These transportation containers are designed to meet the safety and transportation requirements for flammable liquids. They are usually made of steel and are equipped with safety devices such as pressure relief valves, emergency shut - off valves, and grounding devices.​

5.2 Storage​

• Location: Store isobutanol in a cool, well - ventilated area. The storage area should be away from direct sunlight, heat sources, and ignition sources. It is recommended to store it in a dedicated chemical storage warehouse that is designed to handle flammable liquids. The warehouse should have good ventilation systems to prevent the accumulation of isobutanol vapor.​

• Temperature and Humidity: The storage temperature should be maintained below 30 °C. High temperatures can increase the vapor pressure of isobutanol, which increases the risk of evaporation and fire. The relative humidity in the storage area should be kept below 80% to prevent corrosion of the storage containers.​

• Separation: Isobutanol should be stored separately from oxidizing agents, strong acids, and alkalis. These substances can react with isobutanol, which may cause fire, explosion, or the formation of hazardous by - products. For example, isobutanol can react violently with strong oxidizing agents like potassium permanganate or concentrated sulfuric acid.​

• Fire Protection: The storage area should be equipped with appropriate fire - fighting equipment, such as fire extinguishers (suitable for flammable liquid fires, such as foam, dry - chemical, or carbon dioxide extinguishers), fire hydrants, and fire - resistant barriers. In addition, there should be emergency response plans in place in case of a fire or spill.​

• Container Integrity: Regularly inspect the storage containers for signs of leakage, corrosion, or damage. Any damaged containers should be repaired or replaced immediately to prevent the release of isobutanol into the environment.​

6. Toxicity and Safety​

6.1 Toxicity​

• Oral Toxicity: Isobutanol is of low - to - moderate toxicity. The median lethal dose (LD₅₀) for rats by oral administration is in the range of 2 - 4 g/kg body weight. Ingestion of large amounts of isobutanol can cause symptoms such as nausea, vomiting, headache, dizziness, and in severe cases, it can affect the central nervous system, leading to respiratory depression and coma.​

• Dermal Toxicity: Prolonged or repeated skin contact with isobutanol can cause skin irritation. It can defat the skin, leading to dryness, redness, and cracking. The LD₅₀ value for rabbits by dermal application is around 500 mg/kg. However, the absorption of isobutanol through the skin is relatively slow compared to ingestion or inhalation.​

• Inhalation Toxicity: Inhalation of isobutanol vapor can irritate the respiratory tract. At high concentrations, it can cause coughing, shortness of breath, and irritation of the nose and throat. The threshold limit value (TLV) for isobutanol in the workplace air, as recommended by the American Conference of Governmental Industrial Hygienists (ACGIH), is 50 ppm (150 mg/m³) as a time - weighted average (TWA) for an 8 - hour workday. Exposure to concentrations above this limit for an extended period may pose a risk to workers' health.​

6.2 Safety Precautions​

• Engineering Controls: In workplaces where isobutanol is used or stored, provide local exhaust ventilation or general dilution ventilation to keep the vapor concentration below the TLV. Ventilation systems should be designed to prevent the accumulation of isobutanol vapor in confined spaces. Use explosion - proof electrical equipment and lighting in areas where isobutanol vapor may be present, as isobutanol vapor is flammable and can form explosive mixtures with air.