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Phthalic anhydride = 2-Benzofuran-1,3-dione
CAS Number : 85-44-9
EC Number : 201-607-5
Phthalic anhydride is the organic compound with the formula C6H4(CO)2O.
Phthalic anhydride is the anhydride of phthalic acid. Phthalic anhydride is the principal commercial form of phthalic acid.
Phthalic anhydride was the first anhydride of a commercially available dicarboxylic acid.
This white solid is an important industrial chemical for large-scale production of plasticizers, especially for plastics.
In 2000, the worldwide production volume was estimated at around 3 million tons per year.
Synthesis and production
Phthalic anhydride was first reported by Auguste Laurent in 1836. Early procedures involved the liquid-phase mercury-catalyzed oxidation of naphthalene.
The modern industrial variant process of phthalic anhydride uses vanadium pentoxide (V2O5) as the catalyst in the gas phase reaction with naphthalene using molecular oxygen instead.
The general process of phthalic anhydride involves oxidative cleavage of one of the rings and loss of two of the carbon atoms as carbon dioxide.
An alternative process involves the oxidation of two methyl groups of o-xylene, which is a more atom-economic process.
This reaction is carried out at about 320–400 °C and has the following stoichiometry:
C6H4(CH3)2 + 3 O2 → C6H4(CO)2O + 3 H2O
The reaction proceeds with about 70% selectivity.
About 10% of maleic anhydride is also produced:
C6H4(CH3)2 + 7+1/2 O2 → C4H2O3 + 4 H2O + 4 CO2
Phthalic anhydride and maleic anhydride are recovered by distillation by a series of switched capacitors.
The phthalic anhydride naphthalene pathway (Gibbs phthalic anhydride process or Gibbs-Wohg naphthalene oxidation reaction) was decreased compared to the o-xylene pathway.
Proposed first steps in the vanadium-catalyzed oxidation of naphthalene to phthalic anhydride, where V2O5 is represented as a molecule versus its true expanded structure.
Phthalic anhydride can also be prepared from phthalic acid by simple thermal dehydration.
uses
phthalate esters plasticizers
Phthalic anhydride by alcohollysis reaction.
In the 1980s, about 6.5 million tons of these esters were produced annually, and the scale of production was increasing each year, all from phthalic anhydride.
The process begins with the reaction of phthalic anhydride with alcohols and yields monoesters:
C6H4(CO)2O + ROH → C6H4(CO2 H)CO 2R
Phthalic anhydride secondary esterification is more difficult and requires removal of water:
C6H4(CO2 H)CO 2R + ROH ⇌ C6H4(CO2R)2 + H2O
The most important diester of phthalic anhydride is bis(2-ethylhexyl) phthalate ("DEHP"), which is used in the production of polyvinyl chloride compounds.
Pioneer of dyestuffs
Quinoline Yellow SS is a popular dye obtained from the condensation of phthalic anhydride and 2-methylquinoline.
Phthalic anhydride is widely used in industry for the production of certain dyes.
A well-known application of this reactivity is the preparation of the anthraquinone dye quinizarin by reaction with para-chlorophenol followed by hydrolysis of chloride.
Phenolphthalein can be synthesized by condensing phthalic anhydride with two equivalents of phenol under acidic conditions (hence the name).
Phthalic anhydride was discovered by Adolf von Baeyer in 1871.
Phenolphthalein synthesis
Medicine
Phthalic anhydride treated with cellulose acetate yields cellulose acetate phthalate (CAP), a common enteric coating excipient shown to have antiviral activity.
Phthalic anhydride is a degradation product of CAP.
reactions
Phthalic anhydride is a versatile intermediate in organic chemistry, partly because it is bifunctional and is inexpensively available.
Hydrolysis, alcohollysis, ammonolysis
Hydrolysis with hot water forms ortho-phthalic acid:
C6H4(CO)2O + H2O → C6H4(CO2H)2
Hydrolysis of anhydrides is typically not a reversible process.
However, phthalic acid is easily dried to form phthalic anhydride.
Above 180 °C, phthalic anhydride regenerates.
Chiral alcohols form semi-esters (see above) and these derivatives are generally soluble as they form diastereomeric salts with chiral amines such as brucine.
A related ring-opening reaction involves peroxides to give the useful peroxy acid:
C6H4(CO)2O + H2O2 → C6H4(CO3 H)CO 2H
Phthalimide can be prepared in 95-97% yield by heating phthalic anhydride with aqueous ammonia.
Alternatively, it can be prepared by treating the anhydride with ammonium carbonate or urea.
Phthalic anhydride can also be produced by ammoxidation of o-xylene.
Potassium phthalimide is commercially available and is the potassium salt of phthalimide.
Phthalic anhydride can be prepared by adding a hot solution of phthalimide to a solution of potassium hydroxide; the desired product collapses.
Preparation of aliphatic nitroalkenes
Phthalic anhydride is used to dry short-chain nitro-alcohols to yield nitroalkenes, compounds with a high tendency to polymerize.
Safety
The most likely human exposure to phthalic anhydride is skin contact or inhalation during manufacture or use.
Studies show that exposure to phthalic anhydride can cause rhinitis, chronic bronchitis, and asthma.
The reaction of phthalic anhydride on human health is usually an asthma-rhinitis-conjunctivitis syndrome or a delayed reaction and flu-like symptoms and increased immunoglobulin (E and G) levels in the blood.
Names
Preferred IUPAC name
2-Benzofuran-1,3-dione
other names
Isobenzofuran-1,3-dione
phthalic anhydride
identifiers
CAS Number: 85-44-9
Beilstein Reference: 118515
CHEBI CHEBI:36605
CHEMBL :CHEMBL 1371297
ChemicalSpider:6552
ECHA Information Card: 100.001.461
EC Number: 201-607-5
Gmelin Reference :27200
PubChem Client ID : 6811
RTECS number : TI 3150000
UNII :UVL 263I5BJ
UN number: 2214
CompTox Control Panel (EPA ):TXSID 2021159
Features
Chemical formula: C8H4O3
Molar mass : 148.1 g/mol
Appearance : white flakes
Odor : characteristic , acrid[2]
Density : 1.53 g/cm3, solid; 1.20 g/mL, molten[ 2]
Melting point : 131.6 °C (268.9 °F; 404.8 K)
Boiling point : 295 °C (563 °F; 568 K) sublimes
Solubility in water: 0.62 g/100g (20—25 °C); 19.0 g/100g (100 °C); reacts slowly
Vapor pressure :0.0015 mmHg (20 ° C)[ 2]
Magnetic susceptibility (χ): −67.31×10−6 cm3/mol
Phthalic anhydride appears as a colorless to white glossy solid in the form of needles with a slightly distinctive odour.
It is moderately toxic by inhalation or swallowing and is irritating to the skin.
Melting point 64°F Flash point 305°F. Forms a corrosive solution when mixed with water.
It is used in the manufacture of materials such as artificial resins.
Phthalic anhydride is cyclic dicarboxylic anhydride, which is the anhydride of phthalic acid.
Phthalic anhydride acts as an allergen.
Phthalic anhydride is a cyclic dicarboxylic anhydride and is a member of the 2-benzofurans.
Exposure to phthalic anhydride may occur during its use as a chemical intermediate in the plastics industry.
Phthalic anhydride Acute (short-term) effects in humans from exposure to phthalic anhydride consist of eye, respiratory tract and skin irritation, but no permanent injury.
Chronic (long-term) effects observed in workers exposed to phthalic anhydride include conjunctivitis, rhinitis, rhinoconjunctivitis, bronchitis, and irritation of the skin and mucous membranes of the respiratory tract.
No studies are available on the reproductive, developmental, or carcinogenic effects of phthalic anhydride in humans.
The EPA has not classified phthalic anhydride for carcinogenicity.
Empirical Formula (Hill Notation):C8H4O3
CAS Number: 85-44-9
Molecular Weight:148.12
Beilstein:118515
EC Number: 201-607-5
MDL number:MFCD 00005918
PubChem Item ID: 24859242
NAKRIS:NA.21
General description
Phthalic anhydride is an anhydride of phthalic acid and is an important intermediate in the production of plasticizers, dyes, polyester resins, rubber modifiers and polymers.
Application
Phthalic anhydride can be used as a reactant in the preparation of N-substituted phthalimides, poly(isothianaphthene) and methyl (S)-2-phthalimido-4-methylthiobutanoate.
Packaging
In 2.5 kg poly drum
In 25.500 g glass bottle
Quality Level: 200
class : ACS reagent
vapor density: 5.1 (vs. air)
vapor pressure: <0.01 mmHg ( 20 °C)
analysis : ≥99% / 99.0-100.2%
auto-ignition temperature: 1058 °F
explanation _ limit : 10.4%
sign . residue : ≤0.01%
bp : 284 °C (lit)
mp : 131-134 °C (lights up)
human exposure
Occupational exposure to phthalic anhydride may occur through dermal contact with this compound in workplaces where it is produced or used.
Monitoring data indicate that the general population may be exposed to phthalic anhydride through inhalation of ambient air, ingestion of food and drinking water, and skin contact with this compound and other products containing phthalic anhydride.
Environmental Exposure
As a result of the production and use of phthalic anhydride, it is released into the environment through various waste streams.
Phthalic anhydride has been detected in industrial wastes, diesel exhausts, polyurethane products and hazardous waste sites.
Phthalic anhydride is mostly produced by selective oxidation of o-xylene fed as gas.
Due to the highly exothermic reaction, multitube reactors cooled by molten salts are standard technology.
However, the hotspots associated with reduced selectivity and catalyst deactivation are detrimental in practical operation.
A more near-optimal temperature program can be achieved by changing the design with the addition of an adiabatic reactor to complete the conversion.
The monolith is attractive due to its low pressure drop and ease of integration into the heat exchanger chain commonly used in phthalic anhydride production plants.
The monolithic postreactor was installed and successfully operated in a factory in India with a capacity of 60,000 tons of phthalic anhydride per year.
The monolithic finish reactor is well suited for retrofit in existing plants.
Wacker/Lurgi's new phthalic anhydride plants are equipped with this final reactor system as standard parts of the design.
Phthalic anhydride is an important chemical intermediate in the plastics industry, from which a large number of phthalate esters are derived, which act as plasticizers in synthetic resins.
Phthalic anhydride itself is used as a monomer for synthetic resins such as gliptal, alkyd resins, and polyester resins.
Phthalic anhydride is also used as a precursor to anthraquinone, phthaline, rhodamine, phthalocyanine fluorescein, and xanthene dyes.
Phthalic anhydride is used in the synthesis of primary amines, agricultural fungicide phaltan and thalidomide.
Further reactions with phthalic anhydride yield phenolphthalein, benzoic acid, phthalylsulfathiazole (intestinal antimicrobial agent) and orthophthalic acid.
Sources and Potential Exposure Exposure to phthalic anhydride can occur during the manufacture of phthalate-derived products.
It has been suggested that exposure to phthalic anhydride may result from the use of plastics from which phthalate plasticizers leach, particularly certain medical plastics such as blood bags, plastic syringes and plastic tubing.
Phthalate esters have been identified as environmental pollutants.
Personal Exposure Assessment There is no known medical test to determine if a person has been exposed to phthalic anhydride.
Personal protection: chemical protective clothing with self-contained breathing apparatus.
Sweep up spilled material into closed containers.
If appropriate, moisten first to prevent dusting. Carefully collect the rest.
Then store and dispose of according to local regulations.
Physical description A needle-shaped colorless to white glossy solid with a faintly pronounced odour.
boiling point 563°F
molecular weight 148.12
freezing point/melting point 267.4 °F
Vapor pressure 0.0015 mmHg
flash point 305°F
Vapor density 5.1
Specific gravity 1.53 at 68°F
Ionization potential 10.00 eV
Lower explosion limit (LEL) 1.7%
Upper explosion limit (UEL) 10.5%
NFPA health grade 2
NFPA fire rating 1
Store the filters in the refrigerator and use within 1 month.
After this time, small interfering peaks begin to appear.
These media are prepared by SLTC as needed and are not ready to ship immediately.
Please allow time for SLTC to prepare these media before sampling.
Phthalic anhydride is used to make polymeric resins called alkyd resins, which are mainly used as coatings for household appliances and automobiles.
The para isomer terephthalic acid is also used to make polymers, namely polyesters (see below Derivatives of Carboxylic acids: Carboxylic esters).
Air and Water Reactions
Reacts slowly, usually with water, to form phthalic acid and heat [Merck 11th ed. 1989]. Phthalic acid is slightly soluble in water.
Fire danger
Excerpt from ERG Manual 156 [ Substances - Toxic and/or Corrosive (Flammable / Water Sensitive)]:
Combustible material: combustible but not easily ignited.
The substance reacts with water (some violently) releasing flammable, toxic or corrosive gases and streams.
Vapors can form explosive mixtures with air when heated: explosion hazards indoors, outdoors and in sewers.
Most vapors are heavier than air.
They will spread along the floor and collect in low or confined areas (sewers, basements, tanks).
Vapors may travel to the ignition source and flash back.
Contact with metals may develop flammable hydrogen gas.
Containers may explode when heated or contaminated with water. (ERG, 2016)
health hazard
The solid irritates the skin and eyes, causing coughing and sneezing. The liquid causes severe thermal burns. (USCG, 1999)
Reactivity Profile
Phthalic anhydride reacts exothermically with water.
Reactions are sometimes slow, but can be violent when local heating accelerates their rate.
Acids accelerate the reaction with water. Incompatible with acids, strong oxidizing agents, alcohols, amines and bases.
It undergoes exothermic nitration with fuming nitric acid-sulfuric acid and may yield potentially explosive phthaloyl nitrates or nitrites or mixtures of nitro derivatives thereof.
Phthalic anhydride reacts violently with CuO at high temperatures.
Mixtures of phthalic anhydride and anhydrous CO2 explode violently when heated
The Reagents Below Belongs to the Group(s)
anhydrides
Potentially Incompatible Absorbents
Use with caution: Liquids with this reactive group classification are known to react with the absorbents listed below.
Learn more about absorbents, including what to watch out for...
Cellulose Based Absorbent
Mineral Based and Clay Based Absorbent
dirt/soil
Answer Suggestions
Chemical formula:
C8H4O3
Flash Point: 305°F (NTP, 1992)
Lower Explosive Limit (LEL): 1.7% (NTP, 1992)
Upper Explosive Limit (UEL): 10.4% (NTP, 1992)
Auto-Ignition Temperature: 1058°F (USCG, 1999)
Melting Point: 267.4°F (NTP, 1992)
Vapor Pressure: 0.0002 mm Hg at 68°F; 0.001 mm Hg at 86° F (NTP, 1992)
Vapor Density (By Air): 5.1 (NTP, 1992)
Specific Gravity: 1.2 at 275°F, 1.53 (solid) at 20°C (USCG, 1999)
Boiling Point: 563°F (sublimation) at 760 mm Hg (NTP, 1992)
Molecular Weight: 148.12 (NTP, 1992)
Solubility in Water: Decomposes (NTP, 1992)
Ionization Potential: 10.00 eV (NIOSH, 2016)
IDLH: 60 mg/m3 (NIOSH, 2016)
Phthalic anhydride is a white crystalline solid that is the commercial form of phthalic acid.
The largest markets for phthalic anhydride are phthalate plasticizers, unsaturated polyester resins and alkyd resins for surface coatings.
Commercial phthalic anhydride is 99.8-99.9% pure (generally guaranteed 99.5%) and is available in two forms – flake and molten.
Most of the worldwide consumption of phthalic anhydride is in molten form.
Demand for most of the downstream markets for phthalic anhydride is heavily influenced by general economic conditions.
As a result, phthalic anhydride consumption largely follows the patterns of the leading world economies.
Phthalic anhydride consumption is highly dependent on the construction/remodeling activity (residential and non-residential), automobile manufacturing and original equipment manufacturing.
Phthalic anhydride consumption for unsaturated polyester resin production is expected to increase in 2020–25, but growth will vary by region.
Asian markets, particularly in mainland China, India and Southeast Asia, are expected to see growth in demand, while consumption of unsaturated polyester resins in Japan will decline.
Phthalic Anhydride is an important intermediate used in the production of unsaturated polyester resins and alkyd resins used in the coating industry.
Phthalic anhydride is also widely used as a raw material for phthalate PVC plasticizers such as Perstorp's Emoltene™ 100.
Boiling point 285 °C (1013 hPa)
Density 1.53 g/cm3 (20 °C)
Explosion limit 1.7 - 10.5 %(V)
Flash point 152 °C
Ignition temperature 580 °C
Melting Point 131.6 °C
pH value 2 (6 g/l, H₂O, 20 °C)
Vapor pressure 0.001 hPa ( 26.6 °C)
Bulk density 500 - 700 kg/m3
Resolution 6 g/l (slow degradation
Clear molten liquid used in the manufacture of alkyd resin coatings, unsaturated polyester resins and plasticizers. This product is 99.7% pure.
Although a significant number of chemicals are capable of covalently binding to proteins and thus inducing a sensitization state at sufficient exposure, only a small minority can cause allergic hypersensitivity in the respiratory tract; the vast majority are skin sensitizers only.
The key mechanical drivers for the distinction between phthalic anhydride, skin and respiratory sensitization are already well characterized at the cellular/cytokine level.
However, matters are much less clear, both at the chemical level and in terms of predictive toxicology.
In this article, phthalic anhydride is used as an example because it exhibits a particularly different profile as a chemical allergen.
While most respiratory sensitizers are also known to cause delayed skin reactions, evidence for phthalic anhydride suggests that it only causes immediate allergies.
Chemically, it can be assumed that phthalic anhydride reacts similarly to other respiratory sensitizing anhydrides; Phthalic anhydride is clearly positive in tests predicting skin sensitization and has something in common with all other respiratory chemical allergens.
Thus, in the context of interpretation of predictive toxicology tests for skin sensitization, it is inferred that negative results indicate an absence of both skin and respiratory sensitization capacity.
Phthalic anhydride, it is now clear that chemical allergens exhibit heterogeneity mainly according to the form of allergic disease with which they are associated.
Although there are hundreds of chemicals known to cause skin sensitization associated with the development of allergic contact dermatitis, most of them have never been considered respiratory allergens.
In contrast, other far less numerous chemical allergens are mainly (but not limited to) associated with respiratory sensitization and occupational asthma.
The second group includes diisocyanates, acid anhydrides, chloroplatinate salts and some reactive dyes.
Despite this at least partial dichotomy between chemical allergens in terms of the quality of induced immune responses and the type of allergic reactions they elicit, animal (guinea pig and mouse) models have tested positive for both contact and respiratory chemical allergens. used to identify skin sensitizing chemicals.
In fact, all confirmed chemical allergens that preferentially cause respiratory sensitization elicit positive responses in either or both of the mouse (local lymph node test; LLNA) and guinea pig (maximization test or occluded patch test; GPMT) predictive testing methods.
Indeed, it could be argued that the tests simply identified the sensitizing chemicals and used the dermal exposure route for practical purposes.
Against this background, the purpose of this article is to explore more:
(a) the selectivity of chemical allergens with respect to the form that allergic reactions will take in humans, and
(b) the clear conundrum that different classes of chemicals induce qualitatively different immune responses and cause different types of allergic reactions, both testing positive in animal models to predict skin sensitivity.
This will be investigated with reference to phthalic anhydride, a single and well-known chemical respiratory allergen.
In a recent publication1, some research was noted on the rate of esterification of dibasic acid anhydrides with primary alcohols at room temperature. From the results of titration of cold-soluble acid anhydrides in primary alcohols using potassium hydroxide solution in alcohol as titration agent, it was concluded that mono-ester formation was instantaneous and quantitative; reaction was impossible.
TCC's phthalic anhydride is a toxic, white crystalline compound used in the manufacture of phthalins and other paints, resins, plasticizers and insecticides.
Phthalic anhydride is the anhydride of phthalic acid.
This colorless solid is an important industrial chemical for large-scale production of plasticizers, especially for plastics.
Phthalic anhydride is currently obtained by the catalytic oxidation of ortho-xylene or naphthalene. Phthalic anhydride can also be prepared from phthalic acid.
Phthalic anhydride is a versatile intermediate in organic chemistry, in part because it is bifunctional and readily available.
The primary use of phthalic anhydride (PA) is as a chemical intermediate in the manufacture of plasticizers from polyvinyl chloride (PVC).
Applications
The primary use of TCC's phthalic anhydride (PA) is as a chemical intermediate in the manufacture of plastics from vinyl chloride.
Phthalate esters, which act as plasticizers, are derived from phthalic anhydride.
There is another major use of phthalic anhydride in the manufacture of polyester resins and other minor uses in the manufacture of alkyd resins used in paints and lacquers, some insect repellents and urethane polyester polyols.
Phthalic anhydride has also been used as a rubber anti-scorch and retarder.
The second largest outlet for phthalic anhydride PA is unsaturated polyester resins (UPR), which are often mixed with fiberglass to produce glass fiber reinforced plastic. The main markets are construction, shipping and transportation.
Phthalic anhydride third largest output is PA-based alkyd resins used in solvent-based coatings for architectural, machinery, furniture and fixture applications.
Small-volume uses for PA include the manufacture of dyes and pigments, detergents, herbicides and pesticides, fire retardants, saccharin and polyester resin crosslinking agents.
Features
Phthalic Anhydride Spec TCC – Click to Download
Shipping Information
TCC's Phthalic Anhydride is available for shipping throughout the continental United States with a one (1) week lead time.
Please call (401) 360-2800 for details.
Phthalic Anhydride is available in 1MT net super sacks and 25kg bags palletized with shrinkwrap.
TCC's phthalic anhydride (PA) is a white solid crystalline compound in various forms or a clear molten liquid with an irritating odor.
Phthalic anhydride is slightly soluble in hot water and hydrolyzes to Phthalic Acid. PA is soluble in alcohol and carbon disulfide.
Phthalic anhydride reacts with strong oxidizers and reacts violently when heated with copper oxide or sodium nitrite causing an explosion hazard.
Phthalic anhydride is currently obtained by the catalytic oxidation of ortho-xylene or naphthalene.
When separating phthalic anhydride from the production of by-products such as o-xylene or maleic anhydride in water, a set of "switch capacitors" is required.
Phthalic anhydride can also be prepared from phthalic acid.
Phthalic anhydride is the precursor of various reagents useful in organic synthesis. Important derivatives include phthalimide and many of its derivatives.
Phthalic anhydride is widely used in industry for the production of certain dyes. A well-known application of this reactivity is the preparation of the anthraquinone dye quinizarin by reaction with para-chlorophenol followed by hydrolysis of chloride.
One of the main uses of phthalic anhydride is in the production of “phthalate” plasticizers such as Vestinol 9 DINP (DiIsoNonyl Phthalate), which is used to manufacture flexible PVC (Vinyl) products.
These include, but are not limited to, Wire and Cable applications, coated fabrics, roofing membranes, and swimming pool coatings.
CAS No.: 85-44-9
Synonyms: Isobenzofuran-1,3-dione, 2-benzofuran-1,3-dione
Phthalic anhydride is mainly used as a chemical intermediate in the manufacture of plastics from vinyl chloride.
Geographical distribution
Acid anhydrides are a group of highly reactive chemicals widely used in the formulation of paints and plastics.
These chemicals are used in the synthesis of plasticizers and in the manufacture of epoxy and alkyd resins, as well as a variety of other products, including paints, insecticides, polyester resins and pharmaceuticals. Epoxy and alkyd resins, respectively, are used as components of paints, varnishes, surface coatings, adhesives, encapsulated materials and sealants.
Phthalic anhydride (PA) is a compound with a wide variety of industrial uses.
environment
Phthalic anhydride and Trimelitic anhydride (TMA) are two of the most widely used acid anhydrides in industry.
Phthalic anhydride is an important raw material in Phthalate Ester Plasticizers and polyester formulations for boat hulls and other 'glass reinforced plastic' applications as well as alkyd resins for paints.
The two most common ways of exposure to acid anhydrides in the workplace are inhalation and skin contact.
OVERVIEW
The Phthalic anhydride page contains the latest commercial data for Phthalic anhydride.
Phthalic anhydride trade represents 0.0045% of the total world trade.
Phthalic anhydride is part of Polycarboxylic Acids.
EXPORT
The largest exporters of Phthalic anhydride in 2019 were South Korea ($164M), Belgium ($105M), Chinese Taipei ($85.2M), Russia ($50.1M) and Italy ($45.3M).
IMPORTS
The largest importers of Phthalic anhydride in 2019 were India ($146M), the Netherlands ($66.7M), Germany ($66.1M), the United States ($39.7M) and Indonesia ($36.8M).
TARIFFS
The average tariff for Phthalic anhydride in 2018 was 5.24%, making it the 4085th lowest tariff using the HS6 product classification.
The countries with the highest import tariffs for phthalic anhydride are the Bahamas (40.2%), Bermuda (25%), the Cayman Islands (22%) and the Comoros (18.9%). The countries with the lowest tariffs are Angola (0%), Kenya (0%), Mauritius (0%), Rwanda (0%) and Tanzania (0%).
ARRANGEMENT
Phthalic anhydride is ranked 1353 on the Product Complexity Index (PCI).
DEFINITION
Phthalic anhydride can be used to make polyesters, which are plastics used in the textile, packaging, and other industries.
It is also used in the production of some pesticides such as DDT.
PAN is the principal commercial form of phthalic acid, discovered in 1836.
Phthalic anhydride was the first anhydride of a commercially available dicarboxylic acid, and its importance is comparable to acetic acid.
The most important reaction of PAN is to give esters or polyesters with alcohols or diols.
PAN is a versatile intermediate in organic chemistry. PAN is a precursor to several reagents useful in organic synthesis.
A colorless solid, it is an important industrial chemical for large-scale production of plasticizers, especially for plastics.
PAN is widely used in industry for the production of certain dyes.
A well-known application of this reactivity is in the preparation of the anthraquinone dye quinizarin.
The primary use of PAN is as a chemical intermediate in the manufacture of plastics from vinyl chloride.
Phthalate esters that act as plasticizers are derived from PAN. PAN has another major use in the manufacture of polyester resins and other minor uses in the manufacture of alkyd resins used in paints and lacquers, certain paints, insect repellents and urethane polyester polyols.
Phthalic anhydride has also been used as a rubber scorch inhibitor and retardant (HSDB, 1995; National Cancer Institute (NCI), 1979).
PAN is a chemical intermediate that reacts easily and is easily processed, producing a wide range of products that give a wide range of performance properties at low cost.
IGPL operates its plant based on the processes of its licensor M/s Wacker Chemie GmbH, Germany. The process is Wacker's Von-Heyden's Low Energy Process and the plant was engineered by M/s Lurgi GmbH, Germany. The current capacity of Phthalic Anydrid is 2,22,100 MTPA.
Phthalic anhydride is a white solid obtained from partial oxidation with o-xylene air on a solid bed.
Phthalic anhydride is used in solid or molten form in 500 kg FIBCs.
PA is used as an ingredient in making unsaturated polyester resins and fiber-reinforced plastics used in plasticizers, paints, paints and automobile components.
At room temperature: pure white flaky solid
• Heated: colorless and transparent liquid
The liquid/vapor is flammable.
main ingredient of phthalate
plasticizers, the content of FRP,
paints and spandex
Explanation
Phthalic anhydride is the organic compound with the formula C6H4(CO)2O.
Phthalic anhydride is the anhydride of phthalic acid.
This colorless solid is an important industrial chemical for large-scale production of plasticizers, especially for plastics.
phthalic anhydride
Phthalic anhydride is an important chemical intermediate in the plastics industry, from which a large number of phthalate esters are derived, which act as plasticizers in synthetic resins.
Phthalic anhydride itself is used as a monomer for synthetic resins such as gliptal, alkyd resins, and polyester resins.
Phthalic anhydride is also used as a precursor to anthraquinone, phthaline, rhodamine, phthalocyanine, fluorescein, and xanthene dyes.
Phthalic anhydride is used in the synthesis of primary amines, agricultural fungicide phaltan and thalidomide.
Further reactions with phthalic anhydride yield phenolphthalein, benzoic acid, phthalylsulfathiazole (intestinal antimicrobial agent) and orthophthalic acid.
Chemical properties
Phthalic Anhydride is a moderately flammable, white solid (flake) or a clear, colorless, mobile liquid (molten) Characteristic, pungent, suffocating odour.
Chemical properties
Phthalic anhydride is sparingly soluble in H2O, soluble in alcohol, and sparingly soluble in ether.
physical properties
Colorless to pale cream crystals with a characteristic suffocating odour. Moisture sensitive.
The odor threshold concentration is 53 ppb (cited, Amoore and Hautala, 1983).
uses
The compound is a high-tonnage chemical and is widely used in various industrial organic syntheses.
uses
Phthalic anhydride is used in the manufacture of unsaturated polyesters and as a curing agent for epoxy resins.
When used as a pigment, it may be responsible for sensitivity in ceramic workers.
uses
Phthalic Anhydride is an organic compound and anhydride of phthalic acid (P384480).
Phthalic Anhydride is an important industrial chemical widely used in the large-scale production of plasticizers for plastics.
Recent research has also evaluated Phthalic Anhydride as a potential antibacterial agent.
production of phthalines, phthalates, benzoic acid, synthetic indigo, artificial resins (glyptal).
Intermediate for Plasticizers, Dyes, Dyes and Pigments, Polyester Resins.
Definition
ChEBI: Cyclic dicarboxylic anhydride, which is the anhydride of phthalic acid.
General description
Needle-shaped colorless to white glossy solid with a faintly pronounced odour.
It is moderately toxic by inhalation or swallowing and is irritating to the skin. Melting point 64°F Flash point 305°F.
Forms a corrosive solution when mixed with water. It is used in the manufacture of materials such as artificial resins.
Air and Water Reactions
Reacts slowly, usually with water, to form phthalic acid and heat [Merck 11th ed. 1989].
Phthalic acid is slightly soluble in water.
Reactivity Profile
Phthalic anhydride reacts exothermically with water.
Reactions are sometimes slow, but can be violent when local heating accelerates their rate.
Acids accelerate the reaction with water. Incompatible with acids, strong oxidizing agents, alcohols, amines and bases.
It undergoes exothermic nitration with fuming nitric acid-sulfuric acid and may yield potentially explosive phthaloyl nitrates or nitrites or mixtures of nitro derivatives thereof.
Phthalic anhydride reacts violently with CuO at high temperatures.
Mixtures of phthalic anhydride and anhydrous CO2 explode violently when heated.
health hazard
The solid irritates the skin and eyes, causing coughing and sneezing.
The liquid causes severe thermal burns.
Fire danger
Combustible material: combustible but not easily ignited.
The substance reacts with water (some violently) releasing flammable, toxic or corrosive gases and streams.
Vapors can form explosive mixtures with air when heated: explosion hazards indoors, outdoors and in sewers.
Most vapors are heavier than air.
They will spread along the floor and collect in low or confined areas (sewers, basements, tanks).
Vapors may travel to the ignition source and flash back. Contact with metals may develop flammable hydrogen gas.
Containers may explode when heated or contaminated with water.
Pharmaceutical Applications
Phthalic anhydride reacts with cellulose acetate to form cellulose acetate phthalate (CAP), a common enteric coating excipient shown to have antiviral activity.
Phthalic anhydride is a degradation product of CAP.
contact with allergens
Phthalic anhydride is used in the manufacture of unsaturated polyesters and as a curing agent for epoxy resins.
When used as a pigment, it may be responsible for sensitivity in ceramic workers.
Phthalic anhydride is not in itself responsible for sensitization of the resin used in nail polishes to the phthalic anhydride/trimelitic anhydride/glycol copolymer.
Security profile
Toxic by ingestion. Experimental teratogenic effects. A corrosive eye, skin and mucous membrane irritant.
A common air pollutant. It is flammable when exposed to heat or flame; May react with oxidizing agents.
Moderate explosion hazard in the form of dust when exposed to flame.
The production of this material caused many industrial explosions.
Mixtures containing copper oxide or sodium nitrite explode when heated.
℃ Violent reaction with nitric acid + sulfuric acid on it .
Use CO2, dry chemical to fight fire.
It is used in plasticizers, polyester resins and alkyd resins, paints and pharmaceuticals. See also ANHYDRIDES.
chemical synthesis
Phthalic anhydride is the precursor of various reagents useful in organic synthesis.
Important derivatives include phthalimide and many of its derivatives.
Chiral alcohols form semi-esters (see above) and these derivatives are generally soluble as they form diastereomeric salts with chiral amines such as brucine.
A related ring-opening reaction involves peroxides to give the useful peroxy acid:
C6H4(CO)2O + H2O2 → C6H4(CO3 H)CO 2H.
potential exposure
Phthalic anhydride is used in plasticizers; in the manufacture of phthalins; benzoic acid; alkyd and polyester resins; synthetic indigo; and phthalic acid used as a plasticizer for vinyl resins.
In less alizarin, dye, anthranilic acid production; anthraquinone, diethyl phthalate; dimethyl phthalate; erythrosine, isophthalic acid; methylaniline, phenolphthalein, phthalamide, sulfatalidine and terephthalic acid.
It has also found uses as a pesticide intermediate.
environmental destiny
Chemical/Physical. Reacts with water to form O-phthalic acid.
The hydrolysis half-life is 88 seconds, based on an observed rate constant of 7.9 x 10-9/s.
Pyrolysis of phthalic anhydride in the presence of polyvinyl chloride for 10 minutes at 600 °C gave the following compounds: biphenyl, fluorene, benzophenone, 9-fluorenone, o-terphenyl, 9-phenylfluorene and three unidentified compounds.
Transport
UN2214 Phthalic anhydride with ＞ 0.05% maleic anhydride, Hazard class: 8; Tags: 8-Abrasive material.
Treatment Methods
Distill the anhydrite under reduced pressure.
Deacidify by extraction with hot CHCl3, filtration and evaporation.
The residue is crystallized or sublimated from CHCl3, CC14 or benzene.
Crystallize fractionally from the melt.
Dry under vacuum at 100o.
Pioneer of dyestuffs
Phthalic anhydride is widely used in industry for the production of certain dyes.
A well-known application of this reactivity is the preparation of the anthraquinone dye quinizarin by reaction with parachlorophenol followed by hydrolysis of chloride.
Preparation of phthalate esters
As with other anhydrides, the alcohollysis reaction is the basis for the production of phthalate esters, which are widely used (and controversial - see endocrine disruptor) plasticizers.
In the 1980s, about 6.5×109 kg of these esters were produced per year, and the scale of production was increasing from phthalic anhydride each year.
The process begins with the reaction of phthalic anhydride with alcohols to give monoesters:
C6H4(CO)2O + ROH → C6H4(CO2 H)CO 2R
second esterification is more difficult and requires removal of water :
C6H4(CO2 H)CO 2R + ROHC6H4(CO2R)2 + H2O
The most important diester is bis (2-ethyl hexyl) phthalate ("DEHP"), which is used in the production of polyvinyl chloride.
Toxicity assessment
Phthalic anhydride modulates lipid mediator release and cytokine formation and has sensitizing effects on the respiratory tract.
irritant effect, especially on mucous membranes, is probably due to its hydrolysis to phthalic acid.
inconsistencies
Dust forms an explosive mixture with air. Phthalic anhydride reacts exothermically with water.
Reactions are sometimes slow, but can be violent when local heating accelerates their rate.
Acids accelerate the reaction with water.
Incompatible with acids, strong oxidizing agents, alcohols, amines and bases.
It is converted to phthalic acid in hot water.
Incompatible with oxidants (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fire or explosion.
Keep away from alkaline substances, strong bases, strong acids, oxoacids, epoxides. caustics, ammonia, amines, water. Reacts violently with the heat of copper oxide or sodium nitrite 1.
Waste Disposal
Use a licensed professional waste disposal service to dispose of this material.
Dissolve or mix the material with a flammable solvent and incinerate in a chemical incinerator equipped with an afterburner and scrubber.
All federal, state and local environmental regulations must be followed.
Consult environmental regulatory agencies for guidance on acceptable disposal practices.
Producers of waste containing this pollutant (≥100 kg/month) must comply with EPA regulations governing storage, transportation, treatment and waste disposal.
Phthalic anhydride is the anhydride of phthalic acid.
Phthalic anhydride is soluble in alcohol and some other organic solvents.
Phthalic anhydride is obtained by the catalytic oxidation of ortho-xylene with O2 (oxygen) or by the catalytic oxidation of naphthalene.
By-products of the naphthalene reaction are carbon dioxide and water.
Phthalic anhydride is hydrolyzed with hot water to form ortho-phthalic acid.
Phthalic anhydride, paint (rhodamine, anthraquinone derivatives), insecticides, plasticizers, pharmaceuticals, analytical chemistry, etc. in industry. widely used in production.
Copyright Text available under Creative Commons Attribution/Share Alike
A chemical that can cause allergy symptoms in susceptible individuals.
Acid anhydrides are a group of highly reactive chemicals widely used in the formulation of paints and plastics.
These chemicals are used in the synthesis of plasticizers and in the manufacture of epoxy and alkyd resins, as well as a variety of other products, including paints, insecticides, polyester resins and pharmaceuticals.
Epoxy and alkyd resins are used as components of paints, varnishes, surface coatings, adhesives, encapsulated materials and sealants, respectively).
Phthalic anhydride (PA) is a compound with a wide variety of industrial uses.
Acid anhydrides are potent respiratory irritants known to cause hypersensitivity lung disease, which begins as hypersensitivity pneumonia, commonly known as Epoxy Resin Lung.
Hypersensitivity pneumonia can be triggered by acute or chronic exposure to acid anhydrides.
Acute hypersensitivity pneumonia may be characterized by fever, chills, unproductive cough, chest pains, and dyspnea.
Symptoms associated with chronic hypersensitivity include fever, cough, fatigue, weight loss, and shortness of breath.
It is an organic compound obtained by converting orthoxylin (derived from oil) using catalysts (catalytic oxidation process).
Phthalic anhydride is used for the production of plasticizers and for different types of unsaturated polyester resins and alkyds.
Phthalic Anhydride (PA) is produced through partial oxidation of orth-xylene.
It forms white crystal-like flakes at room temperature.
Phthalic acid is formed when it comes into contact with water. Phthalic Anhydride is widely used to make phthalate esters plasticizers for PVC processing.
History
NIOSH recommends collection with cellulose ester membrane filters, extraction with dilute aqueous ammonia, and analysis by HPLC to determine workplace air exposure to phthalic anhydride (Ref. 5.1.).
Others collected phthalic anhydride on glass fiber filters and extracted with dilute aqueous sodium hydroxide (Ref. 5.2).
Since both of these methods convert the collected phthalic anhydride to phthalic acid and are converted to phthalic acid, they are susceptible to positive interference from any phthalic acid originally present in the air.
Also, filters are not effective at holding vapor and smoke.
Steam as well as aerosol are typically produced in industrial phthalic anhydride processes that take place at high temperatures.
Pfaeffli used a Tenax tube connected downstream in series with a membrane filter to collect any vapor entering the filter (Ref. 5.3.).
Desorbed the filter and adsorbent with methyl t-butyl ether and analyzed directly by GC/ECD for anhydride to eliminate interference from phthalic acid present during sampling.
However, the possibility of the collected anhydrite partially hydrolyzed to phthalic acid before analysis still remains.
OSHA collects phthalic anhydride in isopropanol multipliers and analyzes the resulting half-ester by HPLC.
Phthalic anhydride not only eliminates interference from initially airborne phthalic acid, but also prevents the loss of anhydride through hydrolysis after collection.
However, the sampling technique is cumbersome and potentially inefficient.
The method presented here overcomes the above difficulties by using coated filters for collection.
Phthalic anhydride is collected by veratrylamine-coated glass fiber filters, where the anhydride is derivatized in situ to form an acid-amide (phthalmic acid).
The reaction is rapid and quantitative.
Although cyclic anhydrides are readily converted to cyclic imides with amines via intermediate semiamides (Ref. 5.4.), in this case the product is not a cyclic imide but a semiamide (PHVA).
Phthalic anhydride was confirmed by the independent synthesis of the cyclic imide and by comparing the two infrared spectra (Section 4.13.). Since phthalic acid does not form this derivative, it does not mix.
The phthalic anhydride derivative is stable and has high UV absorption, the latter contributing to the high sensitivity of the analytical procedure.
Phthalic anhydride in the form of vapor, smoke or powder is irritating to the eyes.
Phthalic anhydride is both an irritant and sensitizer to the skin and respiratory tract and may cause asthma upon repeated exposure.
Cats exposed to 3700 mg/m3 phthalic anhydride repeatedly became drowsy, lost their appetite, and vomited.
Liver and kidney damage occurred. Air concentrations of 30 mg/m3 caused conjunctivitis in workers.
At 25 mg/m3, there were signs of mucous membrane irritation.
Workers exposed to indeterminate concentrations of mixed vapors of phthalic acid and phthalic anhydride developed conjunctivitis, bloody nasal discharge, nasal mucosa atrophy, hoarseness, cough, occasional bloody sputum, and bronchitis.
A few cases of bronchial asthma have resulted.
There was skin tenderness with occasional urticaria and an eczematous response.
Phthalic anhydride is a direct but delayed irritant to the skin.
Phthalic anhydride is a more severe irritant in the presence of water due to the pronounced effects of phthalic acid formed.
Prolonged or repeated exposure can also cause dermatitis. (Ref. 5.5.)
workplace exposure
The following list includes some common processes where exposure to phthalic anhydride can occur (Ref. 5.5.):
(1) use in the manufacture of plasticizers for use in polyvinyl chloride, polyvinyl acetate, copolymer resins, cellulosic plastics, alkyd resins and non-drying oils or natural resins to improve properties; manufacture of unsaturated polyester resins for use in structural components, swimming pools, automotive components and luggage
(2) use in the synthesis of dyes; Use in the manufacture of chemicals and chemical intermediates for the manufacture of insecticides, insect repellents, chemical reagents, urethane polymers, perfumes and herbicides
(3) use in the manufacture of pharmaceuticals and pharmaceutical intermediates; manufacture of metallic and acid salts; manufacture of epoxy resins as curing and curing agents
(4) use in the manufacture of fire retardants for use as components of polyester resins
Limit definition parameters
Detection limit of analytical procedure
The detection limit of the analytical procedure is 2.5 ng per injection (injection of 5 µL of 0.5 µg/mL solution).
This is the amount of analyte that gives a peak whose height is approximately 5 times the height of the baseline noise. (Section 4.1.)
Detection limit of the general procedure
the anhydride detection limit is 2.34 µg per sample (0.005 ppm, 0.031 mg/m3).
Phthalic anhydride is the amount of analyte added to the sampler that, after analysis, produces a peak of similar size to the detection limit of the analytical procedure. (Section 4.2.)
Reliable quantification limit
The reliable limit of quantitation (RQL) for phthalic anhydride is 3.59 µg per sample (0.008 ppm, 0.048 mg/m3).
Phthalic anhydride is the smallest amount of analyte added to the sampler that can be measured within the requirements of at least 75% recovery and accuracy of ±25% or better (±1.96 SD). (Section 4.3.)
Unlike the naphthalene-based process, crude phthalic anhydride produced by catalytic air oxidation of o-xylene does not contain polymerizable components that must be eliminated by a polymerization and separation pretreatment prior to the distillation step.
However, the crude product produced from o-xylene contains, in addition to phthalic anhydride, varying amounts of phthalic acid, benzoic acid, maleic acid, maleic anhydride, otoluic acid, phthalide, higher boiling components and a nondistillable residue.
For economic and technical reasons, it is desirable to convert the acids to their anhydrides with separation of water and to completely or partially remove other low-boiling components before entering a distillation plant.
It is customary to carry out this dehydration step with phthalic anhydride such that the entire crude product is heated to temperatures between 190 and 280°C in an agitated vessel or cascade of agitated vessels.
This process can be performed intermittently or continuously, but requires significant investment for a large industrial scale pretreatment plant.
Additionally, residence times of around 5 to 100 hours are common, further increasing the investment capital for existing inventory.
Heating under pressure is carried out to a temperature sufficient to evaporate the more volatile components during the expansion step.
When crude oil is highly contaminated with volatile components, it is not necessary to raise the temperature above 330°C, which corresponds to an absolute pressure of about 8.6 atmospheres.
The temperature is adjusted according to the content of the more volatile impurities, so that, through expansion to the pressure p in the expansion chamber, a temperature is obtained at which the more volatile components evaporate, but with as little phthalic as possible. the anhydride is evaporated. Consequently, the temperature after expansion must be below the boiling temperature of phthalic anhydride at expansion pressure p. In any case, the pressure p is usually about 1.5 to 3.6 atmospheres absolute, p is about 0.1 to 1.0 atmospheres absolute,
and the temperature after expansion is about 180 to 285°C, preferably 220 to 270°C.
With this pretreatment, an unexpectedly high degree of pre-purification is achieved using residence times of the crude phthalic anhydride of less than minutes, preferably only between 1 and 40 minutes.
According to a preferred embodiment of the present invention, phthalic anhydride heated under a pressure p is cooled to below 285 °C by expanding into a chamber under atmospheric pressure.
In this case, since the expansion chamber is under atmospheric pressure (p 1 atmosphere absolute), there is no need for any vacuum equipment or the like. In general, heating the crude phthalic anhydride to a temperature of about 290 to 310°C, preferably 300°C, at a pressure p of about 3.5 to 6.5, preferably 5.5 atmospheres, is sufficient to obtain satisfactory priming after expansion to normal pressure. Purification of phthalic anhydride in less than 60 minutes.
In the first stage, by heating under pressure at high temperatures, the rate of heat transmission to the raw liquid mass is increased, while in the second stage, more liquid is removed by expansion. Components that are easily volatile from the raw liquid are especially improved if expansion is carried out into the expansion chamber by means of a spray nozzle.
Preferably, the gases withdrawn from the expansion step are withdrawn by means of a deflagmator whose surface temperature is maintained at about 180240 C on the gas side.
In this way, excess amounts of any phthalic anhydride that may accidentally evaporate during the expansion step are condensed in the deflegmator.
The temperature range that should be kept in the deflagmator is determined by taking into account that, on the one hand, no phthalic acid should be formed from condensed phthalic anhydride and water, and on the other hand, the waste gas should remove very little phthalic. as much as possible with anhydride.
According to the preferred embodiment, the liquid, crude phthalic anhydride is pumped continuously at C, for example, to a heat exchanger.
Phthalic anhydride, as it flows through the heat exchanger pipes, is heated to the desired temperature, for example, 300 C.
In this way, a continuous heating is made possible, which can then be combined with the continuous operation of the expansion vessel, thus resulting in an overall continuous pretreatment.
Phthalic anhydride is of course also possible to intermittently heat phthalic anhydride in a heated autoclave.
In this case, the phthalic anhydride is properly agitated to improve heat transfer.
Batch -based operation of two autoclaves can be combined with a continuous expansion process by filling and heating a batch of crude phthalic anhydride while the contents of one pressure vessel are emptied into the expansion tank.
Another preferred technique is to finely disperse heated liquid phthalic anhydride in the gas phase of the expansion chamber.
In this way, the more volatile components can glow from the resulting droplets of phthalic anhydride without significant evaporation of the phthalic anhydride.
The phthalic anhydride obtained in the liquid phase after expansion is continuously withdrawn from the expansion chamber.
The phthalic anhydride can be fed directly to a continuously operating distillation plant, or it is also possible to collect the prepurified phthalic anhydride in the expansion tank and feed it in batches into the distillation vessel of a batch still.
Scope of application: Phthalic anhydride is intended for the manufacture of plasticizers, alkyd resins, paints, medical preparations and the rubber industry.
Phthalic anhydride is produced from ortho-xylene as class A, top and first class.
Synonyms
1,2-Benzenedicarboxylic acid anhydride
1,3-Dioxofalan
1,3-Isobenzofurandione
phthalanthione
phthalic acid anhydride
phthalic anhydride
PSA
1,3-Isobenzofurandione [ACD/Directory Name]
118515 [Beilstein]
201-607-5 [EINECS]
2-Benzofuran-1,3-dione [German] [ACD/IUPAC Name]
2-Benzofuran-1,3-dione [ACD/IUPAC Name]
2-Benzofurane-1,3-dione [French] [ACD/IUPAC Name]
85-44-9 [RN]
Anhydrous kyseliny ftalove [Czech]
anhydrite phthalic
Anhydrite phtalique [French]
isobenzofuran-1,3-dione
MFCD00005918 [MDL number]
phthalic acid anhydride
Phthalic anhydride [Wiki]
Phthalsaeureanhydrid [German]
1,2-benzenedicarboxylic acid anhydride
1,2- BENZENDICARBOXYLIC ANHYDRIDE
1,2-benzenedicarboxylicanhydride
1,3-dihydro-1,3-dioxoisobenzofuran
1,3-dihydro-2-benzofuran-1,3-dione
1,3-dioxophthalene
1,3-phthalanion
116369-23-4 [RN]
2,5-Isobenzofurandione
201-607-5MFCD00005918
2-Benzofuran-1,3-dione, Benzo[c]furan-1,3-dione, Isobenzofuran-1,3-dione
75935-32-9 [RN]
anidrid phthalica
Anidrid phtalica [Italian]
Araldite HT 901
Benzene-1,2-dicarboxylic anhydride
ESEN
Phtaalzuuranhydride [Dutch]
Phthalanhydride [Czech]
Ftalowy bezwodnik [Polish]
https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:36605
Isobenzo [b]furan-1,3-dione
Isobenzofuran , 1,3-dihydro-1,3-dioxo-
isobenzofuran-1,3-quinone
o -phthalic acid anhydride
ortho-phthalic acid anhydride
PAN
phthalic anhydride
phthalanion
phthalanhydride
Phthalic Acid Anhydride-d4
Phthalic anhydride, ACS grade
phthalanhydride
