Sodium amalgam

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Surname	Sodium amalgam
CAS number	11110-52-4
H and P phrases	H: 260-314-331-360D-372-410
	P: 201-231 + 232-280-308 + 313-370 + 378-402 + 404

Sodium amalgam is an alloy of sodium and mercury . It is a technically important reducing agent in inorganic chemistry .

Extraction and presentation

It is manufactured on a large scale and is an intermediate product in chlor-alkali electrolysis . Sodium amalgam is decomposed with water to form caustic soda , hydrogen and mercury, which is reused in the circuit for electrolysis .

It can also be made directly by dissolving sodium in mercury.

properties

Sodium amalgam is a gray, brittle solid. The melting point depends on the composition; 20% Na he is 61 ° C . With up to 3% sodium, sodium amalgam is not too sensitive to air, but it must be carefully ensured that it is not exposed to air when it is stored.

If the sodium content is low, the alloy is liquid.
Proportions of sodium	Liquidus temperatures
0.5%	0 °
1.0%	50 °
1.5%	100 °
2.0%	130 °
2.5%	156 °
3.0%	250 °
4.0%	320 °

use

In organic chemistry , sodium amalgam is used for the reduction of nitro compounds , for the hydrogenation of multiple bonds and disulfides , for the reductive dehalogenation of haloparaffins and for splitting off sulfo groups.

It is also used for the production of amalgams of other metals, such as. B. barium, strontium and chromium amalgam by reacting an aqueous solution of the corresponding salt with sodium amalgam. By dissolving the chlorides in ethanol and then reacting them, the amalgams of the rare earths are also easily accessible:

{\ displaystyle {\ ce {3 NaHg_ {x} {} + NdCl3 -> [C_2H_5OH] 3 NaCl (v) + NdHg_ {x} {}}}}

Individual evidence

↑ ^a ^b Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 2061.
↑ ^a ^b ^c Sodium mercury amalgam data sheet from Sigma-Aldrich , accessed on May 23, 2017 ( PDF ).

^ Hans-Dieter Barke, Al Hazari, Sileshi Yitbarek: Misconceptions in Chemistry: Addressing Perceptions in Chemical Education . 1st edition. Springer, 2009, ISBN 978-3-540-70988-6 , pp. 133 ff .

↑ Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 4: M-Pk. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1985, ISBN 3-440-04514-5 , pp. 2727-2728.

↑ LF Audrieth: Preparation of the amalgam . In: Harold Simmons Booth (Ed.): Inorganic Syntheses . tape 1 . McGraw-Hill, Inc., 1939, p. 5-10 (English).

[brauer-1] Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 2061.

[Sigma-2] Sodium mercury amalgam data sheet from Sigma-Aldrich , accessed on May 23, 2017 ( PDF ).

[3] Hans-Dieter Barke, Al Hazari, Sileshi Yitbarek: Misconceptions in Chemistry: Addressing Perceptions in Chemical Education . 1st edition. Springer, 2009, ISBN 978-3-540-70988-6 , pp. 133 ff .

[Römpp-4] Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 4: M-Pk. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1985, ISBN 3-440-04514-5 , pp. 2727-2728.

[IS1-5] LF Audrieth: Preparation of the amalgam . In: Harold Simmons Booth (Ed.): Inorganic Syntheses . tape 1 . McGraw-Hill, Inc., 1939, p. 5-10 (English).