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外観
白色, 結晶性粉末又は塊
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定義
本品は、次の化学式で表される不飽和有機酸である。
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溶解性
水及びエタノールに溶けやすい。
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解説
マレイン酸，不飽和の二塩基酸．五酸化バナジウムを触媒としてベンゼンやブテンを気相酸化して得る．このとき，無水マレイン酸とともに得られるが，反応物を水に吸収させるとマレイン酸のみが得られる．無色の結晶．融点130～131 ℃，沸点138 ℃．pK1 1.94，pK2 6.22．水，エタノール，エーテルに易溶．フマル酸と幾何異性の関係にある．マレイン酸は160 ℃ で容易に無水マレイン酸にかわり，また種々の条件下でフマル酸に異性化する．有機合成上重要なリンゴ酸，コハク酸，酒石酸などの原料となる．アルキド樹脂や不飽和ポリエステル樹脂などの原料にもなる．強い刺激性を有する化合物．
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用途
ポリエステル樹脂原料,医薬原料 、接着剤原料、フマール酸、アルキッド樹脂、合成潤滑油原料
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用途
有機合成原料、酸の一次標準(アルカリ標準液の標定)。
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用途
リンゴ酸やコハク酸の合成原料、アルキド樹脂の原料となるほか、油脂の防腐剤や、羊毛・木綿の染色仕上げ剤、薬剤のマレイン酸塩調製などの用途がある。生体内での役割は少なく、ある種の細菌でフマル酸への異性化酵素がみいだされている。
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化粧品の成分用途
pH調整剤、香料
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説明
Maleic acid is an organic compound that is a dicarboxylic acid, a molecule with two carboxyl groups. Its chemical formula is HO2CCHCHCO2H. Maleic acid is the cis-isomer of butenedioic acid, where as fumaric acid is the trans-isomer. It is mainly used as a precursor to fumaric acid, and relative to its parent maleic anhydride, maleic acid has few applications.
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化学的特性
Maleic acid, also known as maleinic acid and toxilic acid, is a white crystalline (monoclinic) powder and possesses a faint acidulous odor and an astringent taste. It is soluble in water and alcohol. Maleic acid and fumaric acid are the simplest unsaturated carboxylic diacids. These acids experience two-step dissociation in aqueous solutions.They have the same structural formula but different spatial configurations. Fumaric acid is the trans and maleic acid the cis isomer. The physical properties of maleic acid and fumaric acid are very different. The cis isomer is less stable. Maleic acid is used in the preparation of fumaric acid by catalytic isomerization.
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物理的性質
Maleic acid is a less stable molecule than fumaric acid. The difference in heat of combustion is 22.7 kJ·mol?1. The heat of combustion is -1355 kJ / mole. Maleic acid is more soluble in water than fumaric acid. The melting point of maleic acid (135 °C) is also much lower than that of fumaric acid (287 °C). Both properties of maleic acid can be explained on account of the intramolecular hydrogen bonding that takes place in maleic acid at the expense of intermolecular interactions, and that are not possible in fumaric acid for geometric reasons.
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調製方法
Maleic anhydride is the main source of maleic acid produced by
hydration. Maleic anhydride is prepared commercially by the
oxidation of benzene or by the reaction of butane with oxygen in the
presence of a vanadium catalyst.
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定義
ChEBI: Maleic acid is a butenedioic acid in which the double bond has cis- (Z)-configuration. It has a role as a plant metabolite, an algal metabolite and a mouse metabolite. It is a conjugate acid of a maleate(1-) and a maleate.
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主な応用
Maleic acid is an industrial raw material for the production of glyoxylic acid by ozonolysis. It may be used to form acid addition salts with drugs to make them more stable, such as indacaterol maleate. Maleic acid is also used in manufacturing synthetic resins; in textile processing; in preserving oils and fats; to retard rancidity of fats and oils in 1:10,000 (these are said to keep 3 times longer than those without the acid); dyeing and finishing wool, cotton, and silk; preparing the maleate salts of antihistamines and similar drugs.
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反応性
Although not practised commercially, maleic acid can be converted into maleic anhydride by dehydration, to malic acid by hydration, and to succinic acid by hydrogenation (ethanol / palladium on carbon). It reacts with thionyl chloride or phosphorus pentachloride to give the maleic acid chloride (it is not possible to isolate the mono acid chloride). Maleic acid, being electrophilic, participates as a dienophile in many Diels - Alder reactions.
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一般的な説明
Maleic acid is a colorless crystalline solid having a faint odor. Maleic acid is combustible though Maleic acid may take some effort to ignite. Maleic acid is soluble in water. Maleic acid is used to make other chemicals and for dyeing and finishing naturally occurring fibers.
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空気と水の反応
Soluble in water.
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反応プロフィール
Maleic acid is a colorless to white crystalline solid. Moderately toxic. When heated to decomposition Maleic acid emits irritating fumes and acrid smoke [Lewis, 3rd ed., 1993, p. 790].
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危険性
Toxic by ingestion.
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健康ハザード
Inhalation causes irritation of nose and throat. Contact with eyes or skin causes irritation.
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火災危険
Special Hazards of Combustion Products: Irritating smoke containing maleic anhydride may form in fire.
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特徴と使用用途
マレイン酸は、食品添加物用途から工業用途に至るまで、幅広い分野の原料として使用されています。 製薬業界では、pH調整剤および緩衝剤の酸成分として使用されています。医薬品製造においては、塩基性化合物のカウンターイオン種として使用されています。工業用としては、オゾン分解によるの製造のための工業原料として、その他、合成樹脂（不飽和ポリエステル）、塗料、樹脂改質剤、塩ビ安定剤、界面活性剤などのような素材の原料として広く使用されています。
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溶媒溶解性
水、エーテル、アルコールに可溶であり、に難溶。
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応用例（製薬）
Maleic acid is used in the pharmaceutical industry as a pH modifier
and a buffering agent.It is also used to prevent rancidity of oils
and fats; a ratio of 1 : 10 000 is usually sufficient to retard rancidity.
Maleic acid is commonly used as a pharmaceutical intermediate to
form the maleate salts of several categories of therapeutic agents,
such as salts of antihistamines and other drug substances.
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安全性プロファイル
Moderately toxic by
ingestion and skin contact. Passes through
intact skin. A skin and severe eye irritant and
a corrosive. Believed to be more toxic than
its isomer, fumeric acid. Combustible when
exposed to heat or flame. When heated to
decomposition it emits acrid smoke and
irritating fumes.
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安全性
Maleic acid is generally regarded as a nontoxic and nonirritant
material when used at low levels as an excipient. Maleic acid is used
in oral, topical, and parenteral pharmaceutical formulations in
addition to food products.
LD50 (mouse, oral): 2.40g/kg(7)
LD50 (rabbit, skin): 1.56g/kg
LD50 (rat, oral): 0.708g/kg
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職業ばく露
Maleic acid is used to make artificial
resins, antihistamines, and to preserve (retard rancidity) of
fats and oils
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発がん性
In chronic feeding studies, 12
Osborne–Mendel rats per group were fed 0.5, 1.0, or 1.5%
maleic acid in their diets for 2 years. Concentrations of 1.0
and 1.5% maleic acid retarded the growth rate of rats, and
all concentrations of maleic acid increased mortality rate;
no tumorigenesis was reported. Toxicological differences
from controls were not marked, and the pathology was
nonspecific.
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貯蔵
Maleic acid converts into the much higher-melting fumaric acid
(mp: 287°C) when heated to a temperature slightly above its melting
point.
Maleic acid is combustible when exposed to heat or flame. The
bulk material should be stored in airtight glass containers and
protected from light. It is recommended not to store it above 25°C.
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輸送方法
UN2215 Maleic acid, Hazard class: 8; Labels:
8-Corrosive material.
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合成方法
酸化パナジウム（V）触媒存在下でベンゼンを気相酸化する事で無水マレイン酸を調製し、これを加水分解する事でマレイン酸が得られます。
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純化方法
Crystallise the acid from acetone/pet ether (b 60-80o) or hot water. Dry it at 100o. [Beilstein 2 H 748, 2 I 303, 2 II 641, 2 III 1911, 2 IV 2199.]
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不和合性
Maleic acid can react with oxidizing materials. Aqueous solutions
are corrosive to carbon steels.
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廃棄物の処理
Dissolve or mix the material
with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal,
state, and local environmental regulations must be
observed. Liquid: incinerate after mixing with a flammable
solvent. Use afterburner for complete combustion. Solid:
dissolve in a flammable solvent or package in paper and
burn. See above
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規制状況(Regulatory Status)
Included in the FDA Inactive Ingredients Database (IM and IV
injections; oral tablets and capsules; topical applications). Included
in nonparenteral and parenteral medicines licensed in the UK.
