Formaldehyde

Paraformaldehyde is a polymerized form of formaldehyde (CHO) and is a stable white crystalline powder with the odor of monomeric formaldehyde. Because pure formaldehyde is unstable at ambient conditions, paraformaldehyde is used as a readily-usable form of formaldehyde at use sites. Then,formaldehyde gas is generated during heating. Paraformaldehyde is used for different applications as a source of either gaseousformaldehyde or solution formaldehyde.

개요파라 포름 알데히드는 페놀을 주성분으로하는 다양한 수지 제조에 널리 사용됩니다. 이것은 포름 알데히드의 중합에 의해 형성된 백색 결정 성 고체이다. 파라 포름 알데히드는 합판 및 파티클 보드에서 바인더로 사용되는 수지를 생산하기 위해 페놀, 우레아, 멜라민 또는 레조 르시 놀과 반응합니다.

용도파라 포름 알데히드는 는 페놀 요소 및 멜라민 수지, 페놀 및 각종 접착제 생산에 사용됩니다.

용도Paraformaldehyde is used as a fumigant, a disinfectant and in the manufacture of synthetic resins like melamine resin, phenol resin and polyacetal resin. It is also used in cell culture. It also serves as a fixative in electron microscopy. It is also used in the preparation of formalin fixatives for tissues or cells. To use the chemical as a fixative, it must be converted to the monomer formaldehyde by heating as formaldehyde is the active chemical in fixation.

일반 설명Paraformaldehyde appears as a white solid with a light pungent odor. A linear polymer of formaldehyde of formula HO(CH2-O)xH where x averages about 30. Soluble in water when x is less than 12; higher polymers are not immediately soluble. Slow dissolution in water proceeds by means of hydrolysis to give fragments of lower x. Flammable, although may take some effort to ignite. Flash point 158 °F. Used in fungicides, bactericides, and in the manufacture of adhesives. A hazard to the environment. Immediate steps should be taken to limit spread to the environment.

Paraformaldehyde [30525-89-4] was first produced in 1859. This polymer, at first mistakenly called dioxymethylene and trioxymethylene, consists of a mixture of poly(oxymethylene) glycols HO-(CH2O)n-H with n=8-100. The formaldehyde content varies between 90 and 99 % depending on the degree of polymerization n (the remainder is bound or free water). It is an industrially important linear polyoxymethylene.Paraformaldehyde is prepared industrially in continuously operated plants by concentrating aqueous formaldehyde solutions under vacuum conditions. At first, colloidal, waxy gels are obtained, which later become brittle. The use of a fractionating column through which gases were passed dates from about 1925.Paraformaldehyde is currently produced in several steps which are carried out at low pressure and various temperatures. Highly reactive formaldehyde is produced under vacuum conditions starting with solutions that contain 50-100 ppm of formic acid and also 1-15 ppm of metal formates where the metals have an atomic number of 23-30 (e.g., Mn, Co, and Cu). The solutions are processed in thin-layer evaporators and spray dryers.