Chlorendic acid

Last updated
Chlorendic acid
Chlorendic acid.png
Names
IUPAC name
1,4,5,6,7,7-hexachlorobicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid
Other names
Chlorendic acid, HET acid, hexachloroendomethylenetetrahydrophthalic acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.003.708 OOjs UI icon edit-ltr-progressive.svg
KEGG
PubChem CID
UNII
  • InChI=1S/C9H4Cl6O4/c10-3-4(11)8(13)2(6(18)19)1(5(16)17)7(3,12)9(8,14)15/h1-2H,(H,16,17)(H,18,19) X mark.svgN
    Key: DJKGDNKYTKCJKD-UHFFFAOYSA-N X mark.svgN
  • C1(C(C2(C(=C(C1(C2(Cl)Cl)Cl)Cl)Cl)Cl)C(=O)O)C(=O)O
Properties
C9H4Cl6O4
Molar mass 388.84366
Melting point 232 °C (450 °F; 505 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Chlorendic acid, or 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid, is a chlorinated hydrocarbon used in the synthesis of some flame retardants and polymers. [1] It is a common breakdown product of several organochlorine insecticides.

Contents

Properties and identification

Chlorendic acid is a white crystalline material with chemical formula C9H4Cl6O4. It is also called HET acid, hexachloroendomethylenetetrahydrophthalic acid, 1,4,5,6,7,7-hexachloro-5-norbornene-2,3-dicarboxylic acid, and 1,4,5,6,7,7 hexachlorobicyclo[2.2.1]-5-heptene-2,3-dicarboxylic acid. [1]

It is produced both as acid and as its anhydride. The anhydride has CAS number 115-27-5 .

Chlorendic acid is slightly soluble in water and nonpolar organic solvents (e.g. benzene, hexane, carbon tetrachloride). It is easily soluble in slightly polar organic solvents (ethanol, methanol, acetone). When heated, it loses water at 200 °C, forming an anhydride with melting point of 230–235 °C. When subject to pyrolysis, it decomposes to hydrochloric acid and various chlorinated compounds. It is resistant to hydrolytic dechlorination. It readily forms salts with metals, and esters.

Chemistry and uses

Chlorendic acid is industrially produced in high volumes by the Diels-Alder reaction. It is used as an intermediate in synthesis of unsaturated flame-retardant polyester resins and plasticizers, and as a finishing flame-retardant treatment for wool. A major use is in the production of fiberglass-reinforced resins for chemical-industry equipment. It can be used to make alkyd resins for use in special inks and paints. It is used as a hardening agent in epoxy resins used in the manufacture of printed circuit boards. When reacted with nonhalogenated glycols, it forms halogenated polyols that can be used as flame retardants in polyurethane foams. It is also used for producing dibutyl chlorendate and dimethyl chlorendate, which are used as reactive flame retardants in plastics. In limited amounts, it is used as an additive in acrylonitrile butadiene styrene copolymer.

Esters and amine salts of chlorendic acid are used as extreme pressure additives in synthetic lubricants.

When used in polymers, whether as a curing agent or as a flame retardant, it bonds covalently to the polymer matrix, which reduces its leaching to the environment. It may, however, be released when such materials are subjected to hydrolysis, and it can be formed by oxidation of chlorinated cyclodiene insecticides (e.g. endosulfan, chlordane, heptachlor, aldrin, dieldrin, endrin, and isodrin). Its half-life in soil is 140–280 days.

In Europe, 80% of chlorendic acid is used in the production of flame-resistant composites for building and transportation, while the rest is used in materials for corrosion-resistant fluid-storage equipment. In the USA, Latin America, and Asia, 20-30% is used in flame-retardant applications and the rest is used in corrosion-resistant plastics.

Related Research Articles

<span class="mw-page-title-main">Carboxylic acid</span> Organic compound containing a –C(=O)OH group

In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group attached to an R-group. The general formula of a carboxylic acid is R−COOH or R−CO2H, with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion.

<span class="mw-page-title-main">Polyethylene</span> The most common thermoplastic polymer

Polyethylene or polythene is the most commonly produced plastic. It is a polymer, primarily used for packaging. As of 2017, over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the total plastics market.

<span class="mw-page-title-main">Thermoplastic</span> Plastic that softens with heat and hardens on cooling

A thermoplastic, or thermosoft plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.

<span class="mw-page-title-main">Epoxy</span> Type of material

Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also collectively called epoxy. The IUPAC name for an epoxide group is an oxirane.

<span class="mw-page-title-main">Flux (metallurgy)</span> Chemical used in metallurgy for cleaning or purifying molten metal

In metallurgy, a flux is a chemical cleaning agent, flowing agent, or purifying agent. Fluxes may have more than one function at a time. They are used in both extractive metallurgy and metal joining.

<span class="mw-page-title-main">Malonic acid</span> Carboxylic acid with chemical formula CH2(COOH)2

Malonic acid (IUPAC systematic name: propanedioic acid) is a dicarboxylic acid with structure CH2(COOH)2. The ionized form of malonic acid, as well as its esters and salts, are known as malonates. For example, diethyl malonate is malonic acid's diethyl ester. The name originates from the Greek word μᾶλον (malon) meaning 'apple'.

<span class="mw-page-title-main">Imide</span>

In organic chemistry, an imide is a functional group consisting of two acyl groups bound to nitrogen. The compounds are structurally related to acid anhydrides, although imides are more resistant to hydrolysis. In terms of commercial applications, imides are best known as components of high-strength polymers, called polyimides. Inorganic imides are also known as solid state or gaseous compounds, and the imido group (=NH) can also act as a ligand.

<span class="mw-page-title-main">Polyimide</span> Class of polymers

Polyimide is a polymer containing imide groups belonging to the class of high-performance plastics. With their high heat-resistance, polyimides enjoy diverse applications in roles demanding rugged organic materials, e.g. high temperature fuel cells, displays, and various military roles. A classic polyimide is Kapton, which is produced by condensation of pyromellitic dianhydride and 4,4'-oxydianiline.

<span class="mw-page-title-main">Bisphenol A</span> Chemical compound used in plastics manufacturing

Bisphenol A (BPA) is a chemical compound primarily used in the manufacturing of various plastics. It is a colourless solid which is soluble in most common organic solvents, but has very poor solubility in water. BPA is produced on an industrial scale by the condensation of phenol and acetone, and has a global production scale which is expected to reach 10 million tonnes in 2022.

In organic chemistry, a dicarboxylic acid is an organic compound containing two carboxyl groups. The general molecular formula for dicarboxylic acids can be written as HO2C−R−CO2H, where R can be aliphatic or aromatic. In general, dicarboxylic acids show similar chemical behavior and reactivity to monocarboxylic acids.

<span class="mw-page-title-main">Maleic anhydride</span> Chemical compound

Maleic anhydride is an organic compound with the formula C2H2(CO)2O. It is the acid anhydride of maleic acid. It is a colorless or white solid with an acrid odor. It is produced industrially on a large scale for applications in coatings and polymers.

<span class="mw-page-title-main">Triethyl phosphate</span> Chemical compound

Triethyl phosphate is an organic chemical compound with the formula (C2H5)3PO4 or OP(OEt)3. It is a colorless liquid. It is the triester of ethanol and phosphoric acid and can be called "phosphoric acid, triethyl ester".

<span class="mw-page-title-main">Extreme pressure additive</span>

Extreme pressure additives, or EP additives, are additives for lubricants with a role to decrease wear of the parts of the gears exposed to very high pressures. They are also added to cutting fluids for machining of metals.

Polysulfones are a family of high performance thermoplastics. These polymers are known for their toughness and stability at high temperatures. Technically used polysulfones contain an aryl-SO2-aryl subunit. Due to the high cost of raw materials and processing, polysulfones are used in specialty applications and often are a superior replacement for polycarbonates.

<span class="mw-page-title-main">Polyester</span> Category of polymers, in which the monomers are joined together by ester links.

Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include naturally occurring chemicals, such as in plants and insects, as well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. Synthetic polyesters are used extensively in clothing.

Polyester resins are synthetic resins formed by the reaction of dibasic organic acids and polyhydric alcohols. Maleic anhydride is a commonly used raw material with diacid functionality in unsaturated polyester resins. Unsaturated polyester resins are used in sheet moulding compound, bulk moulding compound and the toner of laser printers. Wall panels fabricated from polyester resins reinforced with fiberglass—so-called fiberglass reinforced plastic (FRP)—are typically used in restaurants, kitchens, restrooms and other areas that require washable low-maintenance walls. They are also used extensively in cured-in-place pipe applications. Departments of Transportation in the USA also specify them for use as overlays on roads and bridges. In this application they are known AS Polyester Concrete Overlays (PCO). These are usually based on isophthalic acid and cut with styrene at high levels—usually up to 50%. Polyesters are also used in anchor bolt adhesives though epoxy based materials are also used. Many companies have and continue to introduce styrene free systems mainly due to odor issues, but also over concerns that styrene is a potential carcinogen. Potable water applications also prefer styrene free. Most polyester resins are viscous, pale coloured liquids consisting of a solution of a polyester in a reactive diluent which is usually styrene, but can also include vinyl toluene and various acrylates.

<span class="mw-page-title-main">Ammonium polyphosphate</span> Chemical compound

Ammonium polyphosphate is an inorganic salt of polyphosphoric acid and ammonia containing both chains and possibly branching. Its chemical formula is [NH4 PO3]n(OH)2 showing that each monomer consists of an orthophosphate radical of a phosphorus atom with three oxygens and one negative charge neutralized by an ammonium cation leaving two bonds free to polymerize. In the branched cases some monomers are missing the ammonium anion and instead link to three other monomers.

A thermoset polymer matrix is a synthetic polymer reinforcement where polymers act as binder or matrix to secure in place incorporated particulates, fibres or other reinforcements. They were first developed for structural applications, such as glass-reinforced plastic radar domes on aircraft and graphite-epoxy payload bay doors on the Space Shuttle.

Fire-safe polymers are polymers that are resistant to degradation at high temperatures. There is need for fire-resistant polymers in the construction of small, enclosed spaces such as skyscrapers, boats, and airplane cabins. In these tight spaces, ability to escape in the event of a fire is compromised, increasing fire risk. In fact, some studies report that about 20% of victims of airplane crashes are killed not by the crash itself but by ensuing fires. Fire-safe polymers also find application as adhesives in aerospace materials, insulation for electronics, and in military materials such as canvas tenting.

<span class="mw-page-title-main">Alkenylsuccinic anhydrides</span>

Alkenyl succinic anhydrides (ASA) are modified five-membered succinic anhydrides bearing a branched iso-alkenyl chain (C14 to C22). They are colorless, and usually viscous liquids. They are widely used, especially in surface sizing of paper, paperboard, and cardboard, as well as in the hydrophobicization of cellulose fibers. Products treated with it show reduced penetration of aqueous media, such as inks or drinks (like milk or fruit juices).

References

  1. 1 2 PubChem. "Chlorendic acid". pubchem.ncbi.nlm.nih.gov. Retrieved 2022-11-25.