Action of Carbon Dioxide on an Organo-magnesium Halide Grignard

Either acid or alkali can be used to hydrolyse the intermediate compound. The yields in most cases are good, but the reaction can sometimes take another course. (B., 40,1584.) 

Before the following three preparations are attempted, the methods for each should be studied and compared. 

All vessels used in this experiment must be absolutely dry. 12 gms. (1 mol.) of dry bright magnesium turnings (see Preparation 19) are dis- 

The yield increases with aryl-compounds, as may be seen from the two following preparations. 

2-6 gms. (1 mol.) of clean magnesium powder (or thin shavings or ribbon about 2 trims, in width, each piece about 1 cm. long, cleaned with fine emery paper and then with filter paper) are dried in an air oven at 110° for 20 minutes and placed in a dry flask fitted with a reflux. A mixture of 40 c.cs. of dry ether (see p. 216) and 20-4 gms. (1 mol.) of dry iodobenzene of constant boiling point, and a crystal of iodine are then added. The flask is dipped in hot water or heated on a water bath so that the ether boils gently. 

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