PARAFORMALDEHYDE
PARAFORMALDEHYDE
CAS Number: 30525-89-4
EC Number: 608-494-5
Chemical formula: OH(CH2O)nH (n = 8 – 100)
IUPAC name: Polyoxymethylene
Paraformaldehyde is a white, solid polymer of formaldehyde with the pungent, characteristic formaldehyde odor.
Paraformaldehyde is widely used by resin manufacturers seeking low water content or more favourable control of reaction rates when compared to aqueous formaldehyde solutions.
Paraformaldehyde (PFA) is the smallest polyoxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8–100 units.
Paraformaldehyde commonly has a slight odor of formaldehyde due to decomposition.
Paraformaldehyde is a poly-acetal.
Paraformaldehyde is the most commonly used fixative employed for fixation of tissues and cells in immunohistochemistry and immunocytochemistry protocols.
When dissolved in solution, Paraformaldehyde gets depolymerised to formaldehyde which fixes the tissues and cellulose antigens while retaining cellular and subcellular structure.
Paraformaldehyde is a mixture of polymethylene glycols containing 8 to 100 formaldehyde units per molecule.
Paraformaldehyde is commonly used in the hardener component of phenol-resorcinolformaldehyde (PRF) adhesives.
The reactivity of paraformaldehyde can vary considerably depending on how it was manufactured and the age of the material.
When hardener and resin components are mixed, the paraformaldehyde breaks down to release monomeric formaldehyde, which rapidly reacts with the PRF polymer to first cause gelation and ultimately resin cure.
The amount of paraformaldehyde present and its rate of decomposition have a major effect on PRF cure speed.
In addition, recent concerns about formaldehyde emissions make control of paraformaldehyde decomposition an important parameter during manufacture and use of glued-wood-products.
Uses of Paraformaldehyde:
For disinfecting sickrooms, clothing, linen, and sickroom utensils.
Paraformaldehyde is an active ingredient of contraceptive creams.
Paraformaldehyde is used as fumigant; in dentistry; in manufacture of synthetic resins and artificial horn or ivory.
Piroctone Olamine is an anti-dandruff agent used in shampoo formulations.
Paraformaldehyde is used as a agricultural chemical, fungicide, bactericide, and wood preservative.
Paraformaldehyde is the polymerized form of formaldehyde, used in root canal sealers that provide antimicrobial activity.
Paraformaldehyde is used as a fumigant, a disinfectant and in the manufacture of synthetic resins like melamine resin, phenol resin and polyacetal resin.
Paraformaldehyde is also used in cell culture.
Paraformaldehyde also serves as a fixative in electron microscopy.
Paraformaldehyde is also used in the preparation of formalin fixatives for tissues or cells.
Definition of Paraformaldehyde:
A macromolecule composed of repeating methyleneoxy units arising from polymerisation of formaldehyde.
General Description of Paraformaldehyde:
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.
Paraformaldehyde is used in fungicides, bactericides, and in the manufacture of adhesives.
Air & Water Reactions of Paraformaldehyde:
Flammable.
Forms aqueous solution of formaldehyde, often quite slowly.
Paraformaldehyde is a white solid low molecular weight polymer of formaldehyde available in the form of free flowing flakes.
Paraformaldehyde contains 89-91% of formaldehyde and 9-11% of water.
Like formaldehyde in aqueous solution, Paraformaldehyde is very reactive and depolimerizes readily under conventional processing conditions.
Paraformaldehyde is easy to obtain a formaldehyde solution by simply dissolving paraformaldehyde in hot water.
A pH adjustment consistent with the subsequent use of the solution may be made to speed up the process, as at the extreme values of pH the dissolving rate is increased.
The pH of a 37% solution obtained form ALDER paraformaldehyde without any addition is 3.5.
The solution rate is rather high, as working at 55°C with normal agitation and pH adjustment to 8, such solution is ready in only 20 minutes.
However, paraformaldehyde needs not to be previously dissolved in water in order to take part in a chemical reaction.
Easy to store and use, Paraformaldehyde can replace the formaldehyde solution in most reactions, offering outstanding advantages.
In the manufacture of resins the low water content allows for the shortening of reaction time, the increase of the charge size in a given reactor, and the complete or partial elimination of the dehydration stage.
For avoiding the pollution arising at the disposal of the distillate obtained in the thermosetting resin production which is contaminated with organic matter, it is advisable to substitute the aqueous formaldehyde with paraformaldehyde up to the quantity necessary to reach the desired product concentration without any distillation.
Paraformaldehyde storage is less expensive than the storage of formaldehyde solution, which requires expensive tanks and which may be stabilized or kept warm.
General description of Paraformaldehyde:
Paraformaldehyde is also referred as polyoxymethylene.
Paraformaldehyde participates as an external CO source in the synthesis of aromatic aldehydes and esters.
Synthesis of Paraformaldehyde:
Paraformaldehyde forms slowly in aqueous formaldehyde solutions as a white precipitate, especially if stored in the cold.
Formalin actually contains very little monomeric formaldehyde; most of Paraformaldehyde forms short chains of polyformaldehyde.
A small amount of methanol is often added as a stabilizer to limit the extent of polymerization.
Reactions of Paraformaldehyde:
Paraformaldehyde can be depolymerized to formaldehyde gas by dry heating 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.
Use of paraformaldehyde in resin production offers many advantages as compared to aqueous formaldehyde:
-Higher productivity from existing equipment and less water to be removed from the resin product.
-Paraformaldehyde takes the form of prilled, is stable and very easy to store.
Paraformaldehyde storage is less expensive than the storage of formaldehyde solution, which requires expensive tanks and which may need stabilization or be kept warm.
-Use of paraformaldehyde is convenient and safe.
Paraformaldehyde avoids pollution arising from the disposal of the distillate obtained in the thermosetting resin production which is contaminated with organic matter.
-Paraformaldehyde does not need to be dissolved in water in order to take part in a chemical reaction.
-Paraformaldehyde eliminates the risk of transporting liquid formalin, which is notoriously dangerous.
Perfect for small uses straight from the bag.
Application Notes of Paraformaldehyde:
Paraformaldehyde has been used in the past for disinfecting sickrooms, clothing, linen and sickroom utensils.
Paraformaldehyde has been used as a fumigant and in manufacturing synthetic resins & as a fixative in electron microscopy.
Paraformaldehyde is used in the preparation of formalin fixatives for tissues or cells when the samples are to be used in florescence studies.
Usage Statement of Paraformaldehyde:
Unless specified otherwise, MP Biomedical’s products are for research or further manufacturing use only, not for direct human use.
For more information, please contact our customer service department.
Applications of Paraformaldehyde:
-Urea-Formaldehyde Resin
-Phenolic Resin
-Melamine Resin
-Fumigation
-Reagent for organic reactions
-Coating
-Pesticide
-Disinfectant
-Pharmaceuticals
Uses of Paraformaldehyde:
Once paraformaldehyde is depolymerized, the resulting formaldehyde may be used as a fumigant, disinfectant, fungicide, and fixative.
Longer chain-length (high molecular weight) polyoxymethylenes are used as a thermoplastic and are known as polyoxymethylene plastic (POM, Delrin).
Paraformaldehyde was used in the past in the discredited Sargenti method of root canal treatment.
Formaldehyde is CH2O, the simplest aldehyde.
Formalin is the name for saturated (37%) formaldehyde solution.
Thus, a protocol calling for 10% formalin is roughly equivalent to 4% formaldehyde.
Beware though, that some solutions have methanol in them to stop polymerization but this could have a negative effect on your sample.
Paraformaldehyde (PFA) is actually polymerized formaldehyde.
“Pure”, methanol-free formaldehyde can be made by heating the solid PFA.
This might be called paraformaldehyde, but it actually isn’t because it’s not the polymer form.
Paraformaldehyde is not a fixative; it must be depolymerized to formaldehyde in solution.
In cell culture, a typical formaldehyde fixing procedure would involve using a 4% formaldehyde solution in phosphate buffered saline (PBS) on ice for 10 minutes.
In histology and pathology specimens preparation, usually, the fixation step is performed using 10% Neutral Buffered Formalin (4% formaldehyde) for, at least, 24 hours.
Paraformaldehyde is also used to crosslink proteins to DNA, as used in ChIP (chromatin immunoprecipitation) which is a technique to determine which part of DNA certain proteins are binding to.
Paraformaldehyde can be used as a substitute of aqueous formaldehyde to produce the resinous binding material, which is commonly used together with melamine, phenol or other reactive agents in the manufacturing of particle board, medium density fiberboard and plywood.
Formaldehyde, formalin, and paraformaldehyde: what’s the difference?
Aldehyde fixatives act by chemically cross-linking free amine groups on proteins.
Formaldehyde is a commonly used fixative, but it is not stable in solution, because under exposure to light and oxygen it polymerizes and precipitates.
Formaldehyde solution is commonly stabilized by the addition of methanol.
The classic fixative used for pathology is 10% neutral buffered formalin, which is a solution of 10% formaldehyde in sodium phosphate buffer containing up to 1.5% methanol.
Many researchers prefer to use methanol-free formaldehyde for fixation, because methanol can permeabilize cell membranes and affect the morphology of cellular structures like the actin cytoskeleton.
To make formaldehyde solution, the polymerized paraformaldehyde solid must be heated in basic water to form reactive formaldehyde.
Methanol-free fixative solutions prepared from paraformaldehyde solid are commonly referred to as paraformaldehyde solution or PFA.
While technically inaccurate, it serves to distinguish stabilizer-free formaldehyde solution from methanol-stabilized formaldehyde.
Paraformaldehyde solid and formaldehyde solution and vapor are toxic and carcinogenic, so preparing fresh fixative from paraformaldehyde solid is not only inconvenient, but also hazardous.
Biotium’s paraformaldehyde fixative is a convenient and safer alternative to preparing fixative from scratch.
Our paraformaldehyde fixative is stabilized by packaging under inert argon gas in amber glass bottles.
Unlike 16% paraformaldehyde in water that is sold in score-break glass ampoules, our fixative is supplied in easy-to-open, resealable 20 mL amber glass bottles, and is ready-to-use. Unopened bottles can be stored at room temperature for at least 5 years.
After opening, the solution can be stored in the original bottle for at least a month at 4°C, protected from light.
What is the difference between formaldehyde and paraformaldehyde?
Paraformaldehyde is the polymeric form of formaldehyde.
Paraformaldehyde is a solid. Formaldehyde is a gas which when dissolved in water gives a formaldehyde solution.
Commercially available formaldehyde solutions usually contain 10-15% methanol, which prevents the formaldehyde from forming the polymeric paraformaldehyde.
Paraformaldehydes typical properties are:
Appearance: free flowing, white solid flakes with pungent typical formaldehyde odour
Flammability: combustible, with flash point (tag open cup) of about 95°C
Vapour pressure: varies with air humidity, being between 1 and 3 mmHg at 30°C
Melting point: about 150°C in sealed tube; in the open it sublimes rapidly before melting at 130°C to 140°C
Bulk density: varies with degree of compactness: free flowing, about 0.7 kg/lt; packed about 0.75 kg/lt
Color: White
Appearance: Free Flowing Prilled
Molecular Formula: OH-(CH2O)n-H where n=8 to 100 units
Paraformaldehyde Content: 92% ± 1% / 96% ± 1%
Water Content: 8% ± 1% / 4% ± 1%
Reactivity: 2 – 8 min
Mean Particle Size: 250 – 350 µm
Ash: 0.01 – 0.05%
Bulk Density: 650 – 850 kg/m3
Melting Point: 120 – 175 ̊C
pH: 4 – 7
Flammability: combustible, with flash point (tag open cup) of about 93 ̊C
Vapour Pressure: varies with air humidity, being between 23 and 26 mmHg at 25 ̊C
Pellets containing paraformaldehyde (PFA) are sometimes placed behind spouts in tapped sugar maples to prolong sapflow and increase the yield of sap used to make maple syrup.
The practice is controversial because the chemical has been shown to promote decay and is reported to cause cambial dieback around tapholes.
This study reexamined the effects of PFA on tapped sugar maple and determined how these effects also are influenced by time of tapping and spout removal, and by taphole flushing.
A survey of sugarbushes in Wisconsin revealed no relationship between PFA use and cambial dieback and rate of taphole closure.
Other factors including poor tapping techniques and practices, drought, and old age affected these taphole attributes more than PFA.
General Description of Paraformaldehyde:
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.
Paraformaldehyde is used in fungicides, bactericides, and in the manufacture of adhesives.
MAJOR APPLICATIONS of Paraformaldehyde:
-Amino resins / glues for furniture industry (UF, MUF, MF Resins)
-Automotive, paint, oil, textile, paper, pharmaceutical, agrochemicals, adhesives
-Foundry, sanitary, poultry, disinfectant
-Phenolic resin manufacture
-Manufacture of surface coating resins
-Ion exchange resins
-Friction dust industry
-Formaldehyde substitute / formaldehyde donor
-Manufacture of dyestuffs and special plasticizers
Paraformaldehyde (PFA) is the smallest poloxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8–100 units.
MAIN USES of Paraformaldehyde:
-Manufacturing of resins for plastics (e.g. moulding powders) and for the wood industry
-Manufacturing of paints, vamishes, coatings, dyes and other specialty chemicals
-As a bactericide and fungicide
ChemSpider: none
ECHA InfoCard: 100.108.270
UNII: Y19UC83H8E
CompTox Dashboard (EPA): DTXSID8034798
Chemical formula: OH(CH2O)nH (n = 8 – 100)
Appearance: white crystalline solid
Density: 1.42 g·cm−3 (25 °C)
Melting point: 120 °C (248 °F; 393 K)
Solubility in water: low
Paraformaldehyde is an aldehyde.
Paraformaldehyde is the simplest aldehyde in the aldehyde series.
At room temperature and pressure, Paraformaldehyde is a gaseous compound.
Paraformaldehyde is a white solid with a light pungent odor.
Paraformaldehyde is a polymer formed from formaldehyde.
Typically, Paraformaldehyde is composed of 8-100 formaldehyde units.
Paraformaldehyde has chemical and physical properties that are different from formaldehyde.
The main difference between paraformaldehyde and formaldehyde is that paraformaldehyde is in the solid phase at room temperature and pressure whereas formaldehyde is a gas.
Melting point: 120-170 °C (lit.)
Boiling point: 107.25°C (rough estimate)
Density: 0.88 g/mL at 25 °C (lit.)
vapor density: 1.03 (vs air)
vapor pressure: <1.45 mm Hg ( 25 °C)
refractive index: 1.4540 (estimate)
Flash point: 158 °F
storage temp.: 2-8°C
Paraformaldehyde has documented uses as a disinfectant, fungicide, fixation reagent and in the preparation of formaldehyde.
In fluorescence studies, paraformaldehyde has been used as as a formalin fixative to fix cells and tissues.
To use the chemical as a fixative, Paraformaldehyde must be converted to the monomer formaldehyde by heating as formaldehyde is the active chemical in fixation.
The room temperature curing capabilities of PRF adhesives make them the adhesive of choice for bonding timber laminates of large dimension.
With these adhesives, gelation time at moderate temperatures provides a reliable indicator of system reactivity because this test condition closely parallels conditions used during bond formation.
However, gelation evaluations can be timeconsuming and require the use of a test resin system that exhibits a characteristic, time-dependent curing property.
This property is determined primarily by the manner in which the resin was synthesized.
A more universal indication of hardener reactivity should result from a direct measure of paraformaldehyde decomposition to formaldehyde in aqueous solution.
Since cleavage of the formaldehyde polymer is believed to occur primarily at the end of the paraformaldehyde polymer chain, depolymerization will depend upon the number and accessibility of end groups.
Consequently, paraformaldehyde materials of similar molecular weight may release formaldehyde at significantly different rates, depending upon whether the polymer chain end groups are exposed outside or inside the polymer chain bundles.
The rate of formaldehyde release should also be dependent upon molecular weight, particle size, temperature, and pH.
Formaldehyde acts by crosslinking the proteins, primarily the residues of the basic amino acid, lysine resulting in formation of methylene bridges.
Paraformaldehyde is especially effective at preserving secondary structure of proteins as well as tertiary structure.
The purpose of fixation is to preserve the biological sample (tissues or cells) as close to its natural form as possible.
Fixation is usually the first step in the procedure of immunohistochemistry and immunocytochemistry.
TCL119 is a 4% solution of Paraformaldehyde in Phosphate buffered saline.
Method: Prepared in 18.2 megohms-cm ± 1 water.
Storage: 2-8°C
pH: 7.4 ± 0.15
Notes: Expiration 6 months at 2-8°C and 2 years if stored at -20°C
pH Tolerance: 0.15
Paraformaldehyde is the solid form of liquid formaldehyde, formed by the polymerization of formaldehyde with a typical degree of polymerization of 8-100 units.
Since paraformaldehyde is basically a condensed form of formaldehyde, Paraformaldehyde possesses the same characteristics but with a wider range of applications.
Paraformaldehyde (PFA) is the polymerization product of formaldehyde with a typical degree of polymerization of 8–100 units.
Paraformaldehyde is not a fixative itself; it must be depolymerized to formaldehyde in solution.
In cell culture, typical formaldehyde fixing procedure would involve using a 4% formaldehyde solution in phosphate buffered saline (PBS) on ice for 10 minutes.
Fixing ensures that sample cell structures stay intact and that antigens are immobilized, while ideally still permitting unfettered access of antibodies to target antigens.
Our 4% Paraformaldehyde is the most preferred fixative agent as Paraformaldehyde builds covalent cross-links between molecules.
This glues them together hence effectively preserving cells and tissue components.
Use of this 4% paraformaldehyde can guarantee consistency in the physical and chemical properties of the cell, hence no change in chemical and morphology characteristics of the cells and tissues.
Quality Level: 200
vapor density: 1.03 (vs air)
vapor pressure: <1.45 mmHg ( 25 °C)
assay: 95%
form: powder
autoignition temp.: 572 °F
expl. lim.: 73 %
mp: 120-170 °C (lit.)
density: 0.88 g/mL at 25 °C (lit.)
storage temp.: 2-8°C
InChI: 1S/CH2O/c1-2/h1H2
Inchi Key: WSFSSNUMVMOOMR-UHFFFAOYSA-N
SYNONYMS:
Paraform
Paraformaldehyde
Paraformic aldehyde
Polyformaldehyde
Polyoxymethylene
Polyoxymethylene glycol
Flo-mor
aldacide
PARAFORM
Formagen
88.0%(T)
Formagene
Granuform
POLYACETAL
30525-89-4
ACETAL RESIN