アセタール 化学特性,用途語,生産方法
外観
無色～わずかにうすい黄色, 澄明の液体
溶解性
水に可溶 (5.5g/100ml), エタノール, エーテルに可溶。エタノール及びアセトンに極めて溶けやすく、水に溶けにくい。
解説
アセタールは，同一炭素原子が2個のエーテル結合をしたような構造を含む化合物の総称．
"R1，R2 のうちの一つがHのものは，アルデヒドのアセタールで，アルデヒドとアルコールの混合物に塩化水素，塩化亜鉛などの酸触媒を加えて熱すると生じる．R1，R2 がいずれも炭化水素基のものは，ケトンのアセタール(ケタール)で，アルデヒドアセタールと同じようにして合成される．以前はアルデヒドのアセタールをアルデヒドアセタール，ケトンのアセタールをケタールと区別していたが，IUPAC命名規則ではアセタールに統一された．
"アセタールは，一般にアルカリに安定であるが，酸水溶液と温めると容易に加水分解されてカルボニル化合物になるので，合成化学的にはカルボニル基の保護に利用される．アセトアルデヒドジエチルアセタールCH3CH(OC2H5)2を単にアセタールとよぶ場合がある．
森北出版「化学辞典（第2版）
用途
糖類のエチリデン誘導体の合成原料として使われる。香料,溶剤
説明
Acetal is a clear, colourless, and extremely flammable liquid with an agreeable odour. The
vapour is susceptible to cause flash fire. Acetal is sensitive to light and, on storage, may form
peroxides. In fact, it has been reported to be susceptible to autoxidation and should, therefore,
be classified as peroxidisable. Acetal is incompatible with strong oxidising agents and acids.
化学的特性
Acetal is a clear, colorless, and extremely fl
ammable liquid with an agreeable odor. The
vapor may cause fl
ash fi
re. Acetal is sensitive to light and on storage may form peroxides.
In fact, it has been reported to be susceptible to autoxidation and should, therefore, be
classifi
ed as peroxidizable. Acetal is incompatible with strong oxidizing agents and acids.
天然物の起源
Present.in.some.liquors.(e.g.,.sake,.whiskey.and.cognac);.also.detected.and.quantitatively.assessed.in.rums.. Found.in.apple.juice,.orange.juice,.orange.peel.oil,.bitter.orange.juice,.strawberry.fruit,.raw.radish,.Chinese.quince.fruit,.Chinese. quince.flesh,.udo.(Aralia cordata Thunb.)
使用
Acetaldehyde diethyl acetal is used as a flavoring agent to provide fruit, nut, rum, and whiskey flavors.
製造方法
From.ethyl.alcohol.and.acetaldehyde.in.the.presence.of.anhydrous.calcium.chloride.or.small.amounts.of.mineral. acids.(HCl).
定義
A type of organic compound
formed by addition of an alcohol to
an aldehyde. Addition of one alcohol molecule
gives a hemiacetal. Further addition
yields the full acetal. Similar reactions
occur with ketones to produce hemiketals
and ketals.
一般的な説明
A clear colorless liquid with a pleasant odor. Boiling point 103-104°C. Flash point -5°F. Density 0.831 g / cm3. Slightly soluble in water. Vapors heavier than air. Moderately toxic and narcotc in high concentrations.
空気と水の反応
Highly flammable. Forms heat-sensitive explosive peroxides on contact with air. Slightly soluble in water.
反応プロフィール
Acetal can react vigorously with oxidizing agents. Stable in base but readily decomposed by dilute acids. Forms heat-sensitive explosive peroxides on contact with air. Old samples have been known to explode when heated due to peroxide formation [Sax, 9th ed., 1996, p. 5].
健康ハザード
Exposures to acetal cause irritation to the eyes, skin, gastrointestinal tract, nausea, vomit-
ing, and diarrhea. In high concentrations, acetal produces narcotic effects in workers.
火災危険
Highly flammable; flash point (closed cup)
-21°C (-6°F); vapor density 4.1 (air =
1), vapor heavier than air and can travel
some distance to a source of ignition and
flash back; autoignition temperature 230°C
(446°F); vapor forms explosive mixtures
with air, LEL and UEL values are 1.6% and
10.4% by volume in air, respectively (DOT
Label: Flammable Liquid, UN 1088).
.
工業用途
Acetal homopolymer resins have high tensilestrength, stiffness, resilience, fatigue endurance,and moderate toughness under repeatedimpact. Some tough grades can deliver up to 7times greater toughness than unmodified acetalin Izod impact tests and up to 30 times greatertoughness as measured by Gardner impact tests.
Automotive applications of acetal homopolymerresins include fuel-system and seat-beltcomponents, steering columns, window-supportbrackets, and handles. Typical plumbingapplications that have replaced brass or zinccomponents are showerheads, ball cocks, faucetcartridges, and various fittings. Consumer itemsinclude quality toys, garden sprayers, stereocassette parts, butane lighter bodies, zippers,and telephone components. Industrial applicationsof acetal homopolymer include couplings,pump impellers, conveyor plates, gears, sprockets,and springs.
安全性プロファイル
Moderately toxic by ingestion, inhalation, and intraperitoneal routes.A skin and eye irritant. A narcotic. Dangerous fire hazard when exposed to heat or flame; can react vigorously with oxidizing materials. Forms heat-sensitive explosive peroxides on contact with air. when heated to decomposition it emits acrid smoke and fumes. See also ETHERS and ALDEHYDES.
職業ばく露
Used as a solvent; in synthetic perfumes, such as jasmine, cosmetics, flavors; in organic synthesis.
代謝
When acetal was fed at a level of 5% in the diet for 6 days, availability of energy was 64% in chicks and 29% in rats (Yoshida et al. 1970 & 1971). Acetal is rapidly hydrolysed in the stomach(Knoefel, 1934). The resulting acetaldehyde is readily oxidized to acetic acid and eventually to carbon dioxide and water(Williams, 1959).
輸送方法
UN1088 Acetal, Hazard Class: 3; Labels: 3-Flammable liquid. UN1988 Aldehydes, flammable, toxic, n.o.s., Hazard Class: 3; Labels: 3-Flammable liquid, 6.1-Poisonous materials, Technical Name Required
純化方法
Dry acetal over Na to remove alcohols and H2O, and to polymerise aldehydes, then fractionally distil. Or, treat it with alkaline H2O2 at 40-45o to remove aldehydes, then saturate with NaCl, separate, dry with K2CO3 and distil it from Na [Vogel J Chem Soc 616 1948]. [Beilstein 1 IV 3103.]
不和合性
Aldehydes are frequently involved in self-condensation or polymerization reactions. These reactions are exothermic; they are often catalyzed by acid. Aldehydes are readily oxidized to give carboxylic acids. Flammable and/or toxic gases are generated by the combination of aldehydes with azo, diazo compounds, dithiocarbamates, nitrides, and strong reducing agents. Aldehydes can react with air to give first peroxo acids, and ultimately carboxylic acids. These autoxidation reactions are activated by light, catalyzed by salts of transition metals, and are autocatalytic (catalyzed by the products of the reaction). The addition of stabilizers (antioxidants) to shipments of aldehydes retards autoxidation. Presumed to form explosive peroxides on contact with air and light. May accumulate static electrical charges, and may cause ignition of its vapors.
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.
アセタール 上流と下流の製品情報
原材料
準備製品