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Molecular formaldehyde. A colorless gas with a characteristic pungent, irritating odor. It is stable at about 150 °C, but it polymerizes when condensed to a liquid. 1,3,5-Trioxane, with the formula (CH 2 O) 3. It is a white solid that dissolves without degradation in organic solvents. It is a trimer of molecular formaldehyde.
The solubility of gas obeys Henry's law, that is, the amount of a dissolved gas in a liquid is proportional to its partial pressure. Therefore, placing a solution under reduced pressure makes the dissolved gas less soluble. Sonication and stirring under reduced pressure can usually enhance the efficiency.
In his 1803 publication about the quantity of gases absorbed by water, [1] William Henry described the results of his experiments: … water takes up, of gas condensed by one, two, or more additional atmospheres, a quantity which, ordinarily compressed, would be equal to twice, thrice, &c. the volume absorbed under the common pressure of the atmosphere.
The compound is closely related and convertible to the industrially significant derivatives paraformaldehyde ((CH 2 O) n), formaldehyde (H 2 C=O), and 1,3,5-trioxane ((CH 2 O) 3). [3] Methanediol is a product of the hydration of formaldehyde. The equilibrium constant for hydration is estimated to be 10 3, [4] CH 2 (OH) 2 predominates in dilute ...
Paraformaldehyde can be depolymerized to formaldehyde gas by dry heating [2] and to formaldehyde solution by water in the presence of a base, an acid or heat. The high purity formaldehyde solutions obtained in this way are used as a fixative for microscopy and histology. The resulting formaldehyde gas from dry heating paraformaldehyde is flammable.
Despite genuine concerns, formaldehyde is a naturally occurring substance, of which human beings produce approximately 1.5 oz a day as a normal part of a healthy metabolism. Formaldehyde also occurs naturally in many fruits, such as bananas, apples, and carrots, and does not bioaccumulate in either plants or animals. [4]
The most commonly used fixative in histology is formaldehyde. It is usually used as a 10% neutral buffered formalin (NBF), that is approx. 3.7%–4.0% formaldehyde in phosphate buffer, pH 7. Since formaldehyde is a gas at room temperature, formalin – formaldehyde gas dissolved in water (~37% w/v) – is used when making the former fixative.
1,3,5-Trioxane, sometimes also called trioxane or trioxin, is a chemical compound with molecular formula C 3 H 6 O 3. It is a white, highly water-soluble solid with a chloroform -like odor. It is a stable cyclic trimer of formaldehyde , and one of the three trioxane isomers; its molecular backbone consists of a six-membered ring with three ...