Crotonaldehyde is an unsaturated aldehyde with the chemical formula C4H6O. It is used in the production of plastics, resins, and other chemical compounds.
| IUPAC Name | But-2-enal |
| Molecular Formula | C4H6O |
| CAS Number | 123-73-9 |
| Synonyms | Propenal, Crotonic aldehyde, 2-Butenal, (2E)-but-2-enal, Crotylaldehyde |
| InChI | InChI=1S/C4H6O/c1-2-3-4-5/h2-4H,1H3 |
Crotonaldehyde Properties
Crotonaldehyde Formula
The formula of crotonic aldehyde is C4H6O. It represents the chemical composition of crotonic aldehyde, indicating that it consists of four carbon atoms, six hydrogen atoms, and one oxygen atom. The formula provides a concise representation of the atoms and their arrangement within the crotonic aldehyde molecule.
Crotonaldehyde Molar Mass
The molar mass of crotonic aldehyde is the sum of the atomic masses of its constituent elements. Crotonic aldehyde has a molar mass of approximately 70.09 grams per mole (g/mol). This value is obtained by adding the atomic masses of four carbon atoms (12.01 g/mol each), six hydrogen atoms (1.01 g/mol each), and one oxygen atom (16.00 g/mol).
Crotonaldehyde Boiling Point
Crotonic aldehyde has a boiling point of around 104.2 degrees Celsius (°C). This is the temperature at which crotonic aldehyde transitions from a liquid to a gaseous state under standard atmospheric pressure. The boiling point provides important information regarding the volatility and physical properties of crotonic aldehyde.
Crotonaldehyde Melting Point
The melting point of crotonic aldehyde is approximately -76.5°C. This is the temperature at which crotonic aldehyde changes from a solid to a liquid state. The melting point is a crucial characteristic for understanding the behavior of crotonic aldehyde in various processes such as manufacturing, storage, and handling.
Crotonaldehyde Density g/mL
The density of crotonic aldehyde is typically around 0.846 grams per milliliter (g/mL). Density is a measure of mass per unit volume, and it indicates the compactness of a substance. The density of crotonic aldehyde provides insights into its physical properties and behavior when interacting with other substances.
Crotonaldehyde Molecular Weight
The molecular weight of crotonic aldehyde is approximately 70.09 g/mol. It is the sum of the atomic weights of all the atoms in a crotonic aldehyde molecule. Molecular weight is a key factor in various calculations and conversions involving crotonic aldehyde, including determining the amount of substance in moles and establishing stoichiometric relationships in chemical reactions.
Crotonaldehyde Structure
Crotonic aldehyde has a chemical structure consisting of a four-carbon chain with a double bond between the second and third carbon atoms. The terminal carbon bears an aldehyde functional group (―CHO). This structural arrangement imparts crotonic aldehyde with its unique properties and reactivity.
Crotonaldehyde Solubility
Crotonic aldehyde exhibits limited solubility in water, with only about 1.3 grams of crotonic aldehyde dissolving in 100 milliliters (mL) of water at room temperature. However, it is more soluble in organic solvents like ethanol and acetone. The solubility of crotonic aldehyde impacts its behavior and interactions in different chemical processes and applications.
| Appearance | Colorless liquid |
| Specific Gravity | 0.846 g/mL |
| Color | Colorless |
| Odor | Pungent, fruity |
| Molar Mass | 70.09 g/mol |
| Density | 0.846 g/mL |
| Melting Point | -76.5°C |
| Boiling Point | 104.2°C |
| Flash Point | -2.8°C |
| Water Solubility | 1.3 g/100 mL at 25°C |
| Solubility | Soluble in organic solvents like ethanol and acetone |
| Vapour Pressure | 45.3 mmHg at 25°C |
| Vapour Density | 2.42 (air = 1) |
| pKa | 13.0 |
| pH | Approximately 6.4-7.4 |
Crotonaldehyde Safety and Hazards
Crotonic aldehyde poses potential safety hazards and should be handled with caution. It is considered flammable and may ignite if exposed to a flame or heat source. Direct contact with crotonic aldehyde can cause skin and eye irritation, and inhalation of its vapors may irritate the respiratory system. Proper ventilation and personal protective equipment, such as gloves and goggles, should be used when working with crotonic aldehyde. Additionally, it is important to store and handle crotonic aldehyde in a well-ventilated area away from incompatible substances. In case of ingestion or prolonged exposure, medical attention should be sought immediately. Following safety protocols and guidelines is crucial to minimize risks associated with crotonic aldehyde.
| Hazard Symbols | Flammable (F), Irritant (Xi) |
| Safety Description | Keep away from heat and ignition sources. Use in a well-ventilated area. Wear protective gloves and goggles. Avoid contact with skin and eyes. |
| UN IDs | UN 1148 |
| HS Code | 2912.19.0000 |
| Hazard Class | Class 3 – Flammable Liquids |
| Packing Group | PG II |
| Toxicity | Moderately toxic upon ingestion |
Crotonaldehyde Synthesis Methods
Various methods enable the synthesis of crotonic aldehyde. One common method is the Aldol condensation reaction. In this process, acetaldehyde undergoes self-condensation in the presence of a base catalyst, such as sodium hydroxide or potassium hydroxide. The base facilitates the removal of an alpha-hydrogen from one acetaldehyde molecule, forming an enolate ion. The enolate ion then reacts with another molecule of acetaldehyde, resulting in the formation of crotonic aldehyde.
Another method involves the dehydrogenation of crotonic acid. A suitable catalyst, such as copper, zinc, or nickel, facilitates the dehydrogenation of crotonic acid, which can be derived from acrylic acid. The dehydrogenation process eliminates two hydrogen atoms from crotonic acid, resulting in the formation of crotonic aldehyde.
One can synthesize crotonic aldehyde by oxidizing n-butanol. To perform the oxidation reaction, one typically utilizes an oxidizing agent, such as chromium trioxide or potassium dichromate, in the presence of sulfuric acid. The oxidation of n-butanol produces crotonic aldehyde as one of the major products.
These synthesis methods offer different routes to obtain crotonic aldehyde, allowing for its production on an industrial scale. The selection of the synthesis method relies on factors such as the availability and cost of starting materials, desired reaction conditions, and the overall efficiency of the process.
Crotonaldehyde Uses
Crotonic aldehyde finds several uses in various industries and applications. Here are some notable uses:
- Chemical Intermediary: Crotonic aldehyde plays a crucial role in synthesizing various chemicals, including pharmaceuticals, fragrances, and agricultural products.
- Resins and Plastics: It contributes to the structural integrity and performance properties of resins and plastics, enhancing their overall quality.
- Rubber Industry: The rubber industry utilizes crotonic aldehyde as a co-monomer in producing synthetic rubbers, such as nitrile rubber, to improve elasticity and resilience.
- Adhesives: Crotonic aldehyde is an essential component in formulating adhesives that provide strong and durable bonds in woodworking, packaging, and construction applications.
- Flavor and Fragrance Industry: Crotonic aldehyde adds unique flavors and aromas to food products, beverages, and perfumes, enhancing their sensory appeal.
- Agricultural Applications: It serves as an intermediate in synthesizing compounds used for controlling pests and protecting crops, contributing to agricultural applications as a pesticide.
- Polymerization Reactions: Crotonic aldehyde actively participates in polymerization reactions, forming polymeric compounds with diverse properties that find application in coatings, paints, and adhesives.
- Research and Chemical Analysis: It serves as a reference compound in analytical chemistry, enabling the identification and quantification of crotonic aldehyde in various samples.
- Surface Treatment: Crotonic aldehyde modifies material surfaces, imparting desirable characteristics like water repellency and corrosion resistance.
- Pharmaceuticals: It acts as a precursor in synthesizing pharmaceutical compounds, playing a significant role in developing medications for various therapeutic applications.
Crotonic aldehyde’s versatility renders it invaluable in various industries, as it empowers the creation of a diverse array of products that play a crucial role in our daily lives.
Questions:
Q: How many sigma bonds does crotonaldehyde have?
A: Crotonic aldehyde has 9 sigma bonds in its structure.
Q: What is the formula mass of crotonaldehyde, C4H6O?
A: The formula mass of crotonic aldehyde is approximately 70.09 grams per mole (g/mol).
Q: How can you distinguish valeraldehyde and crotonaldehyde?
A: Valeraldehyde has a straight-chain structure with five carbon atoms, while crotonic aldehyde has a four-carbon chain with a double bond between the second and third carbon atoms.
Q: What has crotonaldehyde?
A: Crotonic aldehyde is used in the production of plastics, resins, pharmaceuticals, fragrances, rubber, adhesives, and as a flavor and fragrance component.
Q: Lewis’s structure of crotonaldehyde?
A: The Lewis structure of crotonic aldehyde consists of a four-carbon chain with a double bond between the second and third carbon atoms, and a terminal carbon atom with an aldehyde functional group (―CHO).
Q: Crotonaldehyde NMR?
A: The NMR spectrum of crotonic aldehyde shows characteristic peaks for the different carbon and hydrogen environments in its structure, aiding in its identification and analysis.
Q: Crotonaldehyde hydrogenation of Au and Pt?
A: Both gold (Au) and platinum (Pt) catalysts can be used for the hydrogenation of crotonic aldehyde, leading to the conversion of the double bond to a single bond and the formation of crotonalcohol.