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外観
白色～うすい褐色, 結晶～粉末
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溶解性
水に微溶。アルコール, アセトンに可溶。エーテル, ヘキサンに不溶。アセトン、酢酸エチルに可溶。エーテル、クロロホルム、リグロインに不溶。N,N-ジメチルホルムアミドに溶ける。
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解説
無水ピロメリト酸，白色の固体．融点287 ℃，沸点397～400 ℃．d"1.68．芳香族ジアミンと耐熱，耐薬品性のポリイミド樹脂をつくる．エステル化して塩化ビニル樹脂の可塑剤に使われる．
森北出版「化学辞典（第2版）
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用途
耐熱エポキシ樹脂の架橋剤。アルキド樹脂、合成潤滑油、防さび剤、低揮発可塑剤、アルカリ可溶ポリエステル等の原料。
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製造
無水ピロメリット酸ともいう．ベンゼン核に4個のカルボキシル基が1,2,4,5の位置についたものをピロメリト酸といい，このうち隣接したカルボキシル基から水を除去したものをいう．工業的製法には，1,2,4,5-テトラメチルベンゼン(ジュレン)を酸化する方法およびアントラセンを出発原料とする方法などがある無水ピロメリト酸．
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主な用途／役割
エポキシ樹脂の硬化剤として使用される。
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化学的特性
White powder. Soluble in some organic solvents; hydrolyzes to
the acid when exposed to moisture.
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使用
Pyromellitic dianhydride (PMDA) is employed as a curing agent for epoxy agent resins used for casting, laminating, the manufacture of moulding powders, adhesives and coatings.
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製造方法
Pyromellitic Dianhydride is prepared by gas-phase oxidation of 1,2,4,5-tetramethylbenzene (or related tetrasubstituted benzene derivatives). An idealized equation is:
C6H2(CH3)4 + 6 O2 → C6H2(C2O3)2 + 6 H2O
In the laboratory, it can be prepared by dehydration of pyromellitic acid using acetic anhydride.
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主な応用
Pyromellitic dianhydride (PMDA) has been used extensively as an important monomer in the preparation of a variety of thermoplastics such as polyesters, polycarbonates, polyethers polyethers, plasticizersplasticizers, expoxy resins, etc. Moreover, it is also useful in the preparation of high performance coatings that have been widely employed in many fields in our daily life beacuase of its excellent thermal, oxidative stability and excellent mechanical properties.
Pyromellitic dianhydride (PMDA) is one of several highly reactive acid anhydrides and used extensively in the production of thermoplastics and high-performance coatings. Anhydrides including PMDA are respiratory irritants and immediate-type sensitisers. Some anhydrides have been associated with occupational asthma. PMDA has also been related to occupational asthma.
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一般的な説明
Pyromellitic dianhydride (PMDA) is an acidic anhydride that can be used as a repair agent and as a chain extender in the formation of polyethylene terephthalate (PET) based chain extensions. It is mainly used in the production of thermoplastics and other coating applications.
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危険性
Skin irritant.
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純化方法
Crystallise the dianhydride from ethyl methyl ketone or dioxane. Dry, and sublime it in vacuo.[Beilstein 19 H 196, 19/5 V 407.]
