Question

Difference in state—How does the compound’s use change in a different physical state or when mixed with other compounds at different concentrations?

The compound is formaldehyde, CH2O.

Answer 1

1-. Difference in state: formaldehyde( CH₂O) at normal conditions is in a gaseous state. At temperatures under -20ºC is a clear an colorless liquid.

Due to its physical condition and normal conditions such as gas, which prevents easy handling for subsequent commercialization, it is marketed mainly in the from of an aqueous solution (usually with 30-55% by weight) and a solid hydrated polymer, for formaldehyde (CH₂O)n.H₂O.

2.- Formaldehyde when mixed with other compounds:

formaldehyde is a extremely reactive compound whwn mixed with other compounds; it polymerizes very easily, evcen in cold, giving insoluble polymers that cloud aqueous solutions. to avoid this disadvantage, stabilizers, particularly methyl alcohol, are added.

However, the oxidants react strongly with formaldehyde, most oxidation reactions lead to the formation of formic acid, and complete oxidation results in carbon dioxide and water.

Gaseous formaldehyde: dissolves easily in water, with which it reacts to form an equilibrium mixture of the dissolved monohydrate, methanediol and a series of low molecular weight polymer hydrates, having a formula of the HO(CH₂O)nH type. The gas is easily soluble in alcohols, glycols, amidas and other polar solvents, thereby forming solvates. At low temperates they condensen in a transparent and mobile liquid, which over time becomes a reversible solid polymer.

Polar solvents: such as certain alcohols, amines or acids, catalyze the polymerization of formaldehyde or react with it to form glycols and their derivatives.

Formaldehyde solution: the properties of aqueous formaldehyde depend on whether it is polymerized and hydrated in the dissolved state. Since the composition and properties of the formaldehyde- water system are usually handled as a solution, it is especially important.

Concentrated solutions (more than 30% CH₂O) must be kept warm if precipitation is to be avoided. Alcohols, such as methanol, increase the stability of the solution, due to the formationof hemiacetals. The partial pressure of formaldehyde in equilibrium with the solution is low and is a function of the glycol concentration of the methylenic glycol concentration rather than the total formaldehyde content. It is important to mention that the equilibrium state depends on the concentration and the temperature.