尿素 化学特性,用途語,生産方法
外観
白色の結晶
定義
本品は、次の化学式で表される有機化合物である。
溶解性
水及びエタノールにやや溶けやすく、ジエチルエーテルにほとんど溶けない。
解説
尿素,弱い塩味をもつ無色の柱状晶．融点132 ℃．d420"1.335．nD20"1.484．エタノールや水に易溶，エーテルに難溶．弱塩基性で，酸とは塩を形成する尿素.徐々に熱すると，融点以上でシアヌル酸に，150～170 ℃ でビウレットとアンモニアに，200 ℃ でシアヌル酸トリウレイドに分解する．水溶液は酸やアルカリとの加熱，酵素ウレアーゼの作用によりアンモニアと二酸化炭素に加水分解し，亜硝酸を作用させると窒素を発生する．アルカリ性水溶液中で次亜臭素酸を作用させると窒素を生じるが，この反応はウレアーゼによる反応とともに尿素の定量に用いられる． CO(NH2)2 ＋ 3NaOBr ＋ 2NaOH → N2 ＋ Na2CO3 ＋ 3NaBr ＋ 3H2O 尿素に酸塩化物を作用させるとウレイド(アシル尿素)を生成する．尿素は直鎖状炭化水素，脂肪酸，アルコール類と結晶性の付加物をつくるので，これらの分離精製にも利用される．尿素肥料，尿素樹脂原料として大量に使われるほか，利尿剤や分析用試薬にも用いられる．
森北出版「化学辞典（第2版）
用途
汎用試薬、有機合成原料。
用途
尿素樹脂の原料、接着剤
用途
タンパク質・核酸の変性剤。
用途
有機合成原料、調製液原料。
化粧品の成分用途
保湿.湿潤剤、保水剤、緩衝剤
効能
利尿薬, 皮膚軟化薬, 角質溶解薬
製法
炭酸のジアミド，カルバミン酸のアミドに相当する．ヒトやほかの動物の体内でタンパク質が分解する際に生成し，尿中に排出される(成人では30 g d－1)．植物にもわずかに存在する．クロロギ酸エステル，塩化カルバモイル，炭酸エステル，ホスゲンなどにアンモニアを作用させると生成する．工業的には，液体アンモニアと二酸化炭素を高圧(15.2～25.3 MPa)，高温(180～200 ℃)で反応させると得られる尿素．
主な用途／役割
カゼイン系接着剤に可塑効果、老化防止効果、粘度調整効果がある。
商品名
ウレパール (大塚製薬工場); ウレパール (大塚製薬工場); ケラチナミン (興和); パスタロン (佐藤製薬); パスタロン (佐藤製薬); 尿素 (小堺製薬)
使用上の注意
やや潮解性がある。
説明
Urea is a stable highly water-soluble compound
of high nitrogen content (47%), with good storage
properties that make it the most commonly used nitrogen
fertilizer. The synthesis process has remained essentially
unchanged since it was first developed by the BASF
Corporation in 1922. In this process, liquid ammonia
is reacted with carbon dioxide to produce ammonium
carbamate, which is then dehydrated to form urea. The
reactions are:
2NH3 + CO2 ===? NH2·CO2·NH4
NH2·CO2·NH4 ===? (NH2)2CO + H2O
化学的特性
Urea,CO(HN2)2, also known as carbamide, is a white crystalline powder that has a melting point of l32.7 °C (270 °F). It is a natural product of animal protein metabolism and is the chief nitrogen constituent of urine. Commercially, urea is produced by the reaction of ammonia and carbon dioxide. It is soluble in water, alcohol, and benzene.
天然物の起源
The compound was discovered by Hilaire Rouelle in 1773 as a constituent of urine.
来歴
Urea has the distinction of being the first synthesized organic compound. Until the mid-18th century, scientists believed organic compounds came only from live plants and animals. The first serious blow to the theory of vitalism, which marked the beginning of modern organic chemistry, occurred when Friedrich W?hler (1800 1882) synthesized urea from the two inorganic substances, lead cyanate and ammonium hydroxide: Pb(OCN)2 + 2NH4OH→2(NH2)2CO + Pb(OH)2. W?hler's discoveries on urea occurred while he was studying cyanates; he was attempting to synthesize ammonium cyanate when he discovered crystals of urea in his samples. He first prepared urea in 1824, but he did not identify this product and report his findings until 1828. W?hler's synthesis of urea signaled the birth of organic chemistry.
使用
Urea is a physiological regulator of nitrogen excretion in mammals; synthesized in the liver as an end-product of protein catabolism and excreted in urine. Also occurs normally in skin. Emollient; diu
retic.
調製方法
Urea is an important industrial compound. The synthesis of urea was discovered in 1870.Commercial production of urea involves the reaction of carbon dioxide and ammonia at highpressure and temperature to produce ammonium carbamate. Ammonium carbamate is thendehydrated to produce urea (Figure 96.1). The reaction uses a molar ratio of ammonia tocarbon dioxide that is approximately 3:1 and is carried out at pressures of approximately 150atmospheres and temperatures of approximately 180°C.
定義
A
white crystalline compound made from
ammonia and carbon dioxide. It is used in
the manufacture of urea–formaldehyde
(methanal) resins. Urea is the end product
of metabolism in many animals and is present in urine.
適応症
Urea-containing preparations have a softening and moisturizing effect on the stratum
corneum and, at times, may provide good therapy for dry skin and the pruritus
associated with it. They appear to have an antipruritic effect apart from their hydrating
qualities. Urea compounds disrupt the normal hydrogen bonds of epidermal
proteins; therefore, their effect in dry hyperkeratotic diseases such as ichthyosis
vulgaris and psoriasis is not only to make the skin more pliable but also to help
remove adherent scales. Lactic acid also has a softening and moisturizing effect on
the stratum corneum.
Urea 40% ointment may be useful in removing hypertrophic or dystrophic
psoriatic nails. Subsequent topical therapy to the denuded nail bed and proximal
nail fold may result in regrowth of ‘‘normal’’ nails in half of those treated.
生物学の機能
The use of urea (Ureaphil, Urevert) has declined in
recent years owing both to its disagreeable taste and to
the increasing use of mannitol for the same purposes.
When used to reduce cerebrospinal fluid pressure, urea
is generally given by intravenous drip. Because of its potential
to expand the extracellular fluid volume, urea is
contraindicated in patients with severe impairment of
renal, hepatic, or cardiac function or active intracranial
bleeding.
一般的な説明
Solid odorless white crystals or pellets. Density 1.335 g /cc. Noncombustible.
空気と水の反応
Water soluble.
反応プロフィール
Urea is a weak base. Reacts with hypochlorites to form nitrogen trichloride which explodes spontaneously in air [J. Am. Chem. Soc. 63:3530-32]. Same is true for phosphorus pentachloride. Urea reacts with azo and diazo compounds to generate toxic gases. Reacts with strong reducing agents to form flammable gases (hydrogen). The heating of improper stoichiometric amounts of Urea and sodium nitrite lead to an explosion. Heated mixtures of oxalic acid and Urea yielded rapid evolution of gases, carbon dioxide, carbon monoxide and ammonia (if hot, can be explosive). Titanium tetrachloride and Urea slowly formed a complex during 6 weeks at 80°C., decomposed violently at 90°C., [Chem. Abs., 1966, 64, 9219b]. Urea ignites spontaneously on stirring with nitrosyl perchlorate, (due to the formation of the diazonium perchlorate). Oxalic acid and Urea react at high temperatures to form toxic and flammable ammonia and carbon monoxide gasses, and inert CO2 gas [Von Bentzinger, R. et al., Praxis Naturwiss. Chem., 1987, 36(8), 41-42].
健康ハザード
May irritate eyes.
火災危険
Behavior in Fire: Melts and decomposes, generating ammonia.
农业用途
Fertilizer, Fungicide: Used in fertilizers and animal feeds, as a fungicide,
in the manufacture of resins and plastics, as a stabilizer
in explosives and in medicines, and others. Urea is used
to protect against frost and is used in some pesticides as
an inert ingredient as a stabilizer, as an inhibitor and as an
intensifier for herbicides. Registered for use in EU countries
. Registered for use in the U.S.
製品名
PRESPERSION, 75 UREA®; SUPERCEL
3000®; UREAPHIL®; UREOPHIL®; UREVERT®;
VARIOFORM II®
安全性プロファイル
Moderately toxic by
intravenous and subcutaneous routes.
Human reproductive effects by
intraplacental route: ferthty effects.
Experimental reproductive effects. Human
mutation data reported. A human skin
irritant. Questionable carcinogen with
experimental carcinogenic and
neoplastigenic data. Reacts with sodium
hypochlorite or calcium hypochlorite to
form the explosive nitrogen trichloride.
Incompatible with NaNO2, P2Cl5, nitrosyl
perchlorate. Preparation of the 15N-labeled
urea is hazardous. When heated to
decomposition it emits toxic fumes of NOx.
職業ばく露
Urea is used in ceramics, cosmetics,
paper processing; resins, adhesives, in animal feeds; in the
manufacture of isocyanurates; resins, and plastics; as a stabilizer
in explosives; in medicines; anticholelithogenic, and
others.
環境運命予測
Terrestrial Fate
Urea is expected to have very high mobility in soil. Urea is not
expected to volatilize from dry soil surfaces based on its vapor
pressure. Various field and laboratory studies have demonstrated
that urea degrades rapidly in most soils. Urea is rapidly hydrolyzed
to ammonium ions through soil urease activity, which
produces volatile gases, that is, ammonia and carbon dioxide.
However, the rate of hydrolysis can be much slower, depending
on the soil type, moisture content, and urea formulation.
Aquatic Fate
Urea is not expected to adsorb to suspended solids and sediments.
Volatilization from water surfaces is not expected. Urea
is rapidly hydrolyzed to ammonia and carbon dioxide in
environmental systems by the extracellular enzyme urease,
which originates from microorganisms and plant roots.
Atmospheric Fate
According to a model of gas/particle partitioning of semivolatile
organic compounds in the atmosphere, urea, which has
a vapor pressure of 1.2×10
-5mm Hg at 251°C, will exist in
both the vapor and particulate phases in the ambient atmosphere.
Vapor-phase urea is degraded in the atmosphere by
reaction with photochemically produced hydroxyl radicals; the
half-life for this reaction in air is estimated to be 9.6 days.
代謝
The high analysis and good handling properties of urea
have made it the leading nitrogen fertilizer, both as
a source of nitrogen alone or when compounded with
other materials in mixed fertilizers. Although an excellent
source of nitrogen, urea can present problems unless
properly managed; due to its rapid hydrolysis to ammonia,
significant volatilization loss of this may occur if prilled
or granular urea is applied to and left on the soil
surface without timely incorporation. Mixtures of urea
and ammonium nitrate for use in mixed fertilizers are also
more highly hygroscopic than ammonium nitrate itself.
純化方法
Crystallise urea twice from conductivity water using centrifugal drainage and keeping the temperature below 60o. The crystals are dried under vacuum at 55o for 6hours. Levy and Margouls [J Am Chem Soc 84 1345 1962] prepared a 9M solution in conductivity water (keeping the temperature below 25o) and, after filtering through a medium-porosity glass sinter, added an equal volume of absolute EtOH. The mixture was set aside at -27o for 2-3 days and filtered cold. The precipitate was washed with a small amount of EtOH and dried in air. Crystallisation from 70% EtOH between 40o and -9o has also been used. Ionic impurities such as ammonium isocyanate have been removed by treating the concentrated aqueous solution at 50o with Amberlite MB-1 cation-and anion-exchange resin, and allowing it to crystallise on evaporation. [Benesch et al. J Biol Chem 216 663 1955.] It can also be crystallised from MeOH or EtOH, and is dried under vacuum at room temperature. [Beilstein 3 H 42, 3 I 19, 3 II 35, 3 III 80.]
不和合性
Violent reaction with strong oxidizers,
chlorine, permanganates, dichromates, nitrites, inorganic
chlorides; chlorites, and perchlorates. Contact with hypochlorites
can result in the formation of explosive compounds.
廃棄物の処理
Controlled incineration in
equipment containing a scrubber or thermal unit to reduce
nitrogen oxide emissions.
尿素 上流と下流の製品情報
原材料
準備製品
Reactive Black KN-BN
ureaformaldelyde resin UF
1,2,3,4-テトラヒドロ-2,4-ジオキソ-5-ピリミジンカルボン酸エチル
2,4-DICHLOROTHIENO[3,2-D]PYRIMIDINE
5,6-ジヒドロ-5-メチルウラシル
ニトロフラゾン
Tanning agent for white leather
synthetic carbamider ring tanning agent No.1
1-(2-アミノエチル)-2-イミダゾリジノン
DIRECT FAST BLACK G
カルバミルコリンクロリド
ヘキサヒドロピリミジン-2,4-ジオン
2-[(4-メトキシ-2-ニトロフェニル)アゾ]-N-(2-メトキシフェニル)-3-オキソブタンアミド
6-アミノウラシル (4-)
flame retardane ZR-01
2,4-ジクロロチエノ[3,2-d]ピリミジン
2,6-ジクロロ-4,8-ジピペリジノピリミド[5,4-d]ピリミジン
biodegrddable finishing agent for fabric
ビ尿素
1-(1,3-DIHYDRO-1-OXOISOBENZOFURAN-3-YL)UREA
1,1'-イソブチリデンビス尿素
1,3,5-トリアザペンタン-2,5-ジオン
1,3-ビス(ヒドロキシメチル)-4,5-ジヒドロキシイミダゾリジン-2-オン
1,2-ジヒドロ-1-フェニル-3H-1,2,4-トリアゾール-3-オン
トロクロセン
シモキサニル
ピリミド[5,4-d]ピリミジン-2,4,6,8-テトラオール
尿素·過酸化水素
5-(1-メチルブチル)バルビツル酸
Amino moulding plastic
Tableware cleaner
synthetic tanning agent PNC
rubber latex 104T/C
ビュウレット
ETHYL 2-HYDROXYPYRIMIDINE-5-CARBOXYLATE
1-フェニルセミカルバジド
アリル尿素
Water flush fertilizer
2-HYDROXY-4-PHENYLPYRIMIDINE-5-CARBOXYLIC ACID
2,4-DIHYDROXYTHIENO[3,2-D]PYRIMIDINE