Table of Contents
What are Aldehydes?
Aldehyde Group – Definition: Aldehydes are organic compounds with the general formula R-CHO, where R is a carbon chain. They are derivatives of ketones, where a hydrogen atom has been replaced by an aldehyde group (-CHO). Aldehydes are volatile, colorless, and flammable. They are soluble in water and have a pungent, irritating odor.
Aldehydes are general reactants in many organic reactions. They are commonly used to form carbon-carbon bonds, to produce esters, and to prepare Schiff bases. Aldehydes can also be used as precursors to amines.
Aldehydes are synthesized by the oxidation of alcohols. The most common method is the Wacker process, which uses palladium as a catalyst.
Naturally Occurring Aldehydes
- Aldehydes are organic molecules that contain a carbon-oxygen double bond adjacent to a hydrogen atom. The simplest aldehyde is formaldehyde, which has the molecular formula CH2O. Other aldehydes include acetaldehyde (CH3CHO) and benzaldehyde (C6H5CHO).
- Aldehydes are relatively stable, but they can be oxidized to carboxylic acids. This process is called oxidation. For example, the aldehyde formaldehyde can be oxidized to the carboxylic acid methyl formate.
- Aldehydes are widely used in industry. For example, acetaldehyde is used to produce ethanol, and formaldehyde is used to produce urea.
Physical State of Matter
There are three physical states of matter: solid, liquid, and gas.
In a solid, the particles (atoms or molecules) are closely packed together and held in place by strong forces. In a liquid, the particles are still close together, but they are able to move around one another. In a gas, the particles are far apart and move around freely.
Boiling Points
The boiling point of a liquid is the temperature at which the vapor pressure of the liquid is equal to the atmospheric pressure. At the boiling point, the liquid will change to a vapor. The boiling point is affected by the strength of the intermolecular forces in the liquid and the vapor pressure of the surrounding atmosphere.
Solubility Insoluble in water
- An aldehyde is a molecule containing a carbon-oxygen double bond and a terminal carbon-oxygen single bond. The carbon atom of the aldehyde is bonded to an hydrogen atom and to an oxygen atom. The aldehyde functional group is characterized by the presence of a carbonyl group, C=O, which is bonded to two carbon atoms.
- Aldehydes are soluble in organic solvents such as ethanol and acetone, but are insoluble in water. The reason for the lack of solubility in water is the strong polarity of the water molecule. The oxygen atom of the water molecule is more electronegative than the carbon atom, and therefore the water molecule is polar. The aldehyde molecule is also polar, due to the presence of the carbonyl group, C=O. The polarity of the aldehyde molecule and the water molecule causes them to repel each other, and this results in the aldehyde being insoluble in water.
Aldehydes and ketones are two classes of organic compounds.
Aldehydes are compounds that contain a carbon-oxygen double bond and a terminal carbon-oxygen single bond. The carbon atom in the double bond is called the carbonyl carbon. The simplest aldehyde is formaldehyde, which has the formula CH2O.
Ketones are compounds that contain a carbon-oxygen double bond and two carbon-carbon single bonds. The carbon atom in the double bond is called the ketone carbon. The simplest ketone is acetone, which has the formula CH3COCH3.
Reduction of greenhouse gases
- Greenhouse gases are emitted into the atmosphere as a result of human activities such as the burning of fossil fuels and deforestation. These gases form a “blanket” around Earth that trap energy from the sun. This trapped energy makes the Earth’s atmosphere warm, and disturbs the Earth’s climate.
- Reducing greenhouse gas emissions is important because it helps to prevent the Earth’s atmosphere from becoming too warm, which could lead to dangerous and harmful changes in the Earth’s climate. Some of the ways that we can reduce greenhouse gas emissions include using energy efficient appliances and vehicles, conserving energy, and reducing deforestation.
