Thermolysis

The thermolysis is a chemical reaction in which a starting material by heating into a plurality of products is decomposed. In contrast to thermal decomposition (= pyrolysis ), thermolysis is used specifically to produce defined products or reactive intermediate stages.

In the case of rotary kiln ( pyrolysis ), however, very complex reactions take place that differ greatly depending on the process temperature. Here, too, new connections are formed, so that the rotary kiln (pyrolysis) below 1000 ° C is actually a rotary kiln thermolysis.

Examples

• If the salt ammonium chloride is heated , it decomposes, releasing the gases ammonia and hydrogen chloride .

NH ₄ Cl (s) → NH ₃ (g) + HCl (g)

• Mercury (II) oxide , a red, crystalline solid, breaks down into mercury (formation of silvery droplets) and oxygen when heated .

2 HgO (s) → 2 Hg (l) + O ₂ (g)

• Burning lime (chemical calcium carbonate ) releases the gas carbon dioxide. What remains is the white, crumbly "burnt lime" (chemical calcium oxide ).

CaCO ₃ (s) → CaO (s) + CO ₂ (g)

• Heated to dicumyl peroxide , the bond between the two oxygen atoms is homolytically cleaved and there are two Phenylalkyloxid - radicals . These are used industrially as free radical initiators during polymerization .

• Diacyl peroxides - e.g. B. Dibenzoyl peroxide - are split homolytically with the formation of two radicals.

• When azides are heated, nitrenes are formed with the elimination of nitrogen (N ₂ ) .

• When diazoalkanes are heated, nitrogen (N ₂ ) carbenes are formed .

Decarboxylation of the proteinogenic α- amino acid L - hydroxyproline .

• Thermal decarboxylation (splitting off of carbon dioxide ) of amino acids with the formation of amines .

Individual evidence

1. ^ Brockhaus ABC chemistry . VEB FA Brockhaus Verlag, Leipzig 1965, pp. 72-73.
2. ^ Brockhaus ABC chemistry . VEB FA Brockhaus Verlag, Leipzig 1965, p. 1160.
3. ↑ Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 1: A-Cl. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1979, ISBN 3-440-04511-0 , pp. 570-571.
4. ^ Siegfried Hauptmann : Organic Chemistry , 2nd edition, VEB Deutscher Verlag für Grundstoffindustrie, Leipzig 1985, ISBN 3-342-00280-8 , pp. 413-414.
5. ^ Siegfried Hauptmann: Organische Chemie , Verlag Harri Deutsch, 1985, ISBN 3-87144-902-4 , p. 537.
6. ^ Siegfried Hauptmann: Organic chemistry . Verlag Harri Deutsch, 1985, ISBN 3-87144-902-4 , p. 531.
7. ↑ ^{a b} Sabine Wallbaum, Thomas Mehler, Jürgen Martens : Decarboxylation of α-Amino Acids containing two and three Stereogenic Centers: A Simple One-Step Procedure to Prepare Two Opticall Active β-Amino Alcohols and a Bicyclic Pyrrolidine Derivative . In: Synth. Commun. 24, 1994, pp. 1381-1387, doi: 10.1080 / 00397919408011741 .