Malonsäure

Gefahreninformationscode (GHS)

• Bildanzeige (GHS)

  

• Alarmwort

  Achtung

• Gefahrenhinweise

  H318：Verursacht schwere Augenschäden.

• Sicherheit

  P280：Schutzhandschuhe/Schutzkleidung/Augenschutz tragen.

  P305+P351+P338：BEI KONTAKT MIT DEN AUGEN: Einige Minuten lang behutsam mit Wasser spülen. Eventuell vorhandene Kontaktlinsen nach Möglichkeit entfernen. Weiter spülen.

Malonic acid Chemische Eigenschaften,Einsatz,Produktion Methoden

• ERSCHEINUNGSBILD

  WEISSE KRISTALLE.

• CHEMISCHE GEFAHREN

  Mittelstarke Säure in wässriger Lösung. Reagiert mit starken Oxidationsmitteln.

• ARBEITSPLATZGRENZWERTE

  TLV nicht festgelegt (ACGIH 2005).
  MAK nicht festgelegt (DFG 2005).
  

• AUFNAHMEWEGE

  Aufnahme in den Körper durch Inhalation und durch Verschlucken.

• INHALATIONSGEFAHREN

  Verdampfung bei 20°C vernachlässigbar; eine gesundheitsschädliche Partikelkonzentration in der Luft kann jedoch beim Dispergieren schnell erreicht werden.

• WIRKUNGEN BEI KURZZEITEXPOSITION

  WIRKUNGEN BEI KURZZEITEXPOSITION:
  Die Substanz reizt die Haut und reizt stark die Augen und die Atemwege.

• LECKAGE

  Verschüttetes Material in abgedeckten Behältern sammeln. Dann mit viel Wasser wegspülen.

• R-Sätze Betriebsanweisung:

  R20/22:Gesundheitsschädlich beim Einatmen und Verschlucken.
  R41:Gefahr ernster Augenschäden.
  R36/37/38:Reizt die Augen, die Atmungsorgane und die Haut.
  R22:Gesundheitsschädlich beim Verschlucken.

• S-Sätze Betriebsanweisung:

  S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
  S36/39:Bei der Arbeit geeignete Schutzkleidung und Schutzbrille/Gesichtsschutz tragen.
  S37/39:Bei der Arbeit geeignete Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
  S36:DE: Bei der Arbeit geeignete Schutzkleidung tragen.

• Aussehen Eigenschaften

  C3H4O4. Farbloses, feinkristallines Pulver, fast geruchlos. Hygroskopisch, feuchtigkeitsempfindlich und brennbar.

• Gefahren für Mensch und Umwelt

  Gesundheitsschädlich beim Verschlucken. Reizt die Augen, Haut und Schleimhäute.
  Zersetzung oberhalb 140鳦 unter Freisetzung von Essigsäure.
  LD50 (oral, Ratte) 1310 mg/kg
  Nicht ins Abwasser gelangen lassen.

• Schutzmaßnahmen und Verhaltensregeln

  Lagerung trocken unter 15鳦.
  Schutzhandschuhe als kurzzeitiger Staubschutz.

• Verhalten im Gefahrfall

  Staubentwicklung und Substanzkontakt vermeiden. Trocken aufnehmen. Der Entsorgung zuführen. Nachreinigen.
  Kohlendioxid, Wassernebel, Pulver, Schaum.
  Brennbar.

• Erste Hilfe

  Nach Hautkontakt: Mit reichlich Wasser abwaschen.
  Nach Augenkontakt: Mit reichlich Wasser bei geöffnetem Lidspalt mindestens 10 Minuten ausspülen. Augenarzt hinzuziehen.
  Nach Einatmen: Frischluft.
  Nach Verschlucken: Viel Wasser trinken lassen, Erbrechen auslösen. Arzt hinzuziehen.
  Nach Kleidungskontakt: Kontaminierte Kleidung entfernen.
  Ersthelfer: siehe gesonderten Anschlag

• Sachgerechte Entsorgung

  In Wasser lösen, neutralisieren, dann in wässrige Lösemittelabfälle.

• Beschreibung

  Malonic acid (MA), also known as propanedioic acid, is a dicarboxylic acid with structure CH2(COOH)2. It have three kinds of crystal forms, of which two are triclinic, and one is monoclinic. That crystallized from ethanol is white triclinic crystals.It decomposes to acetic acid and carbon dioxide at 140℃. It does not decompose at 1.067×103~1.333×103Pa vacuum, but directly sublimates. The ionised form of malonic acid, as well as its esters and salts, are known as malonates. For example, diethyl malonate is malonic acid's ethyl ester. The name originates from Latin malum, meaning apple.

• Chemische Eigenschaften

  Malonic acid is a white crystalline solid that decomposes at approximately 135°C. It has high solubility in water and oxygenated solvents and exhibits greater acidity than acetic acid, which has a pK value of 4.75. The pKa values for the loss of its first and second protons are 2.83 and 5.69, respectively. It is slightly soluble in pyridine. It can decompose to formic acid and carbon dioxide in case of potassium permanganate. Since that malonic acid generates carbon dioxide and water after heated without pollution problems, it can be directly used as aluminum surface treatment agent.

• Verwenden

  Malonic acid is used as an intermediate in the manufacture of barbiturates and other pharmaceuticals. It is a component used as a stabilizer in many high-end cosmetic and pharmaceutical products. Malonic acid is also used as building block in chemical synthesis, specifically to introduce the molecular group -CH2-COOH. It is used for the introduction of an acetic acid moiety under mild conditions by Knoevenagel condensation and subsequent decarboxylation.

• Application

  Malonic acid is acts as a building block in organic synthesis. It is also useful as a precursor for polyesters and alkyd resins, which is used in coating applications, thereby protecting against UV light, corrosion and oxidation. It acts as a cross linker in the coating industry and surgical adhesive. It finds application in the production of specialty chemicals, flavors and fragrances, polymer cross linkers and pharmaceuticals.

• Definition

  ChEBI: Malonic acid is an alpha,omega-dicarboxylic acid in which the two carboxy groups are separated by a single methylene group. It has a role as a human metabolite. It is a conjugate acid of a malonate(1-).

• synthetische

  Malonic acid is usually produced from chloroacetic acid.
  Reaction: The chloroacetic acid is added to the reaction kettle by adding sodium carbonate aqueous solution to generate sodium chloroacetate aqueous solution, and then 30% sodium cyanide solution is slowly added dropwise, and the reaction is carried out at a predetermined temperature to generate sodium cyanoacetate. After the cyanation reaction is completed, add sodium hydroxide for heating and hydrolysis to generate sodium malonate solution, concentrate, then dropwise add sulfuric acid for acidification to generate malonic acid, filter and dry to obtain the product.
  
  This method often does not produce a pure enough product or the pure product has an extremely low yield. Industrially, malonic acid is also produced by hydrolyzing dimethyl malonate or diethyl malonate. This manufacturing method is able to bring about a higher yield and purity, but the organic synthesis of malonic acid through these processes is extremely costly and environmentally hazardous.

• Reaktionen

  In a well - known reaction, malonic acid condenses with urea to form barbituric acid. Malonic acid is also frequently used as an enolate in Knoevenagel condensations or condensed with acetone to form Meldrum's acid. The esters of malonic acid are also used as a - CH2COOH synthon in the malonic ester synthesis.

• Biologische Funktion

  Malonic acid is the classic example of a competitive inhibitor of the enzyme succinate dehydrogenase (complex II), in the respiratory electron transport chain.It binds to the active site of the enzyme without reacting, competing with the usual substrate succinate but lacking the ?CH2CH2? group required for dehydrogenation. This observation was used to deduce the structure of the active site in succinate dehydrogenase.

• Allgemeine Beschreibung

  White crystals or crystalline powder. Sublimes in vacuum.

• Air & Water Reaktionen

  Water soluble.

• Reaktivität anzeigen

  Malonic acid is a carboxylic acid. Carboxylic acids donate hydrogen ions if a base is present to accept them. They react in this way with all bases, both organic (for example, the amines) and inorganic. Their reactions with bases, called "neutralizations", are accompanied by the evolution of substantial amounts of heat. Neutralization between an acid and a base produces water plus a salt. Carboxylic acids with six or fewer carbon atoms are freely or moderately soluble in water; those with more than six carbons are slightly soluble in water. Soluble carboxylic acid dissociate to an extent in water to yield hydrogen ions. The pH of solutions of carboxylic acids is therefore less than 7.0. Many insoluble carboxylic acids react rapidly with aqueous solutions containing a chemical base and dissolve as the neutralization generates a soluble salt. Carboxylic acids in aqueous solution and liquid or molten carboxylic acids can react with active metals to form gaseous hydrogen and a metal salt. Such reactions occur in principle for solid carboxylic acids as well, but are slow if the solid acid remains dry. Even "insoluble" carboxylic acids may absorb enough water from the air and dissolve sufficiently in Malonic acid to corrode or dissolve iron, steel, and aluminum parts and containers. Carboxylic acids, like other acids, react with cyanide salts to generate gaseous hydrogen cyanide. The reaction is slower for dry, solid carboxylic acids. Insoluble carboxylic acids react with solutions of cyanides to cause the release of gaseous hydrogen cyanide. Flammable and/or toxic gases and heat are generated by the reaction of carboxylic acids with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides. Carboxylic acids, especially in aqueous solution, also react with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), to generate flammable and/or toxic gases and heat. Their reaction with carbonates and bicarbonates generates a harmless gas (carbon dioxide) but still heat. Like other organic compounds, carboxylic acids can be oxidized by strong oxidizing agents and reduced by strong reducing agents. These reactions generate heat. A wide variety of products is possible. Like other acids, carboxylic acids may initiate polymerization reactions; like other acids, they often catalyze (increase the rate of) chemical reactions Malonic acid is incompatible with strong oxidizers. Malonic acid is also incompatible with bases and reducing agents.

• Hazard

  Strong irritant.

• Brandgefahr

  Flash point data for Malonic acid are not available; however, Malonic acid is probably combustible.

• Flammability and Explosibility

  Not classified

• Biotechnological Applications

  The calcium salt of malonic acid occurs in high concentrations in beetroot. It exists in its normal state as white crystals. Malonic acid is the classic example of a competitive inhibitor: It acts against succinate dehydrogenase (complex II) in the respiratory electron transport chain.

• läuterung methode

  Crystallise malonic acid from *benzene/diethyl ether (1:1) containing 5% of pet ether (b 60-80o), wash with diethyl ether, then recrystallise it from H2O or acetone. Dry it under vacuum over conc H2SO4. [Beilstein 2 IV 1874.]

Malonic acid Upstream-Materialien And Downstream Produkte

Malonsäure Anbieter Lieferant Produzent Hersteller Vertrieb Händler.

Global(827)Suppliers

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