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Org. Synth. 1923, 3, 65
DOI: 10.15227/orgsyn.003.0065
DI-p-TOLYLMERCURY
[Mercury, di-p-tolyl-]
Submitted by F. C. Whitmore, N. Thurman, and Frances H. Hamilton.
Checked by J. B. Conant and F. C. Whidden.
1. Procedure
In a 2-l. round-bottomed flask fitted with a reflux condenser and an efficient glass stirrer, are placed 700 cc. of 95 per cent ethyl alcohol, 100 g. (0.3 mole) of recrystallized p-tolylmercuric chloride (p. 519), and 160 g. (1.1 moles) of sodium iodide (Note 1) (75 per cent excess). The mixture is boiled with vigorous stirring (Note 2) for fifteen hours; the solid does not entirely enter into solution at any time. The mixture is then thoroughly cooled and filtered by suction and the solid washed with water until free of inorganic halide. It is then dried in an air oven at 40° and recrystallized from 500 cc. of boiling xylene (Note 3). In this way 45–50 g. (78–85 per cent of the theoretical amount) of a product melting at 238° is obtained.
2. Notes
1. Mercury compounds of the type RHgX can be changed to those of the type R2Hg, by almost any neutral or alkaline reagent which tends to change mercuric ions to metallic mercury or to a stable complex ion. Some of these reagents are inorganic iodides, thiocyanates, thiosulfates, sulfides, hydrosulfites, ferrous hydroxide, sodium amalgam, metallic sodium, and sodium stannite. Preliminary experiments indicated that potassium thiocyanate was a good reagent for preparing di-p-tolylmercury; but it was later found that the use of sodium iodide with vigorous stirring gave even better results.
2. Stirring decreases the time required for the reaction and increases the yield. Without stirring it is practically impossible to obtain a product which is free from halogen.
3. Since the di-p-tolylmercury has practically the same solubility in xylene as the tolylmercuric iodide and chloride, the latter will be present in the recrystallized product if the reaction has not gone to completion. A trace of unchanged product may readily be detected by the metallic sodium test for inorganic halides.
3. Discussion
Di-p-tolylmercury can be prepared from p-bromotoluene with sodium amalgam;1 from p-tolylmercuric chloride with copper in pyridine,2 or with hydrazine hydrate and sodium carbonate;3 from p-tolyllithium and mercuric chloride;4 and from the double salt of p-toluene-diazonium chloride and mercuric chloride with copper powder in cold acetone.5
This preparation is referenced from:

References and Notes
  1. Dreher and Otto, Ann. 154, 171 (1870); Wurtz, Compt. rend. 68, 1298 (1869); La Coste and Michaelis, Ann. 201, 246 (1880).
  2. Hein and Wagler, Ber. 58, 1499 (1925).
  3. Gilman and Barnett, Rec. trav. chim. 55, 565 (1936).
  4. Austin, J. Am. Chem. Soc. 54, 3726 (1932).
  5. Nesmejanov and Kahn, Ber. 62, 1018 (1929).

Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

mercuric ions

metallic mercury

inorganic iodides

thiocyanates

thiosulfates

sulfides

hydrosulfites

tolylmercuric iodide and chloride

double salt of p-toluene-diazonium chloride

ethyl alcohol (64-17-5)

sodium carbonate (497-19-8)

copper,
copper powder (7440-50-8)

acetone (67-64-1)

pyridine (110-86-1)

sodium,
metallic sodium (13966-32-0)

mercuric chloride (7487-94-7)

p-tolylmercuric chloride (539-43-5)

xylene (106-42-3)

sodium stannite

sodium iodide (7681-82-5)

ferrous hydroxide

potassium thiocyanate (333-20-0)

hydrazine hydrate (7803-57-8)

p-Bromotoluene (106-38-7)

DI-p-TOLYLMERCURY,
Mercury, di-p-tolyl- (537-64-4)

p-tolyllithium