Magnesium formate

Magnesium formate decomposes (613—723 K) directly to the oxide [1024] and the barium salt melts prior to anion breakdown. 

The addition of nickel formate to magnesium formate significantly reduced the decomposition temperature [1151]. The acceleratory period characteristic of the decomposition of pure Mg(HC02)2 was eliminated and the value of E was substantially diminished. For the double (Zn,Ba) and (Cu,Ba) formates, the rate of decomposition [1152] of the less stable component (Zn or Cu) was slower and that of the more stable component (Ba) more rapid than the values characteristic of pure preparations of these substances. 

Fig. 6.46. Acylation of Grignard compounds with magnesium carboxylates usually impossible (with magnesium carboxylate A), but feasible with sterically favored magnesium formate (B) or electronically favored magnesium(tri-fluoracetate) (C). These reactions allow the construction of aldehydes and trifluoro-methylketones, respectively.

Formic acid salts can also be prepared by the reaction of CO2 and II2 with an alkali metal manganese pcntacarbonyK such as NaMn(CO). in an inert solvent [164]. Magnesium format was synthesized directly from CO2, II3 and Mg under mild conditions 165], The catalytic fixation of Hj and CO2 was carried out in the TiCU 2THF/Mg/THF system and the following mechanism has been proposed (Scheme 4). 

Figure 8.16. A. Experimental and simulated Mg MAS NMR spectrum of magnesium formate dihydrate (simulation based on data from the MQMAS spectrum). B. Two-dimensional Mg MQMAS spectrum of magnesium formate dihydrate showing the two inequivalent Mg sites resolved. From Sham and Wu (2000) by permission of the American Chemical Society.

The preparation of cyanohydrin was described in connection with the synthesis of acrylates (see Section 11.3.2.2). As for dehydration, this can be conducted in the liquid phase, around -200°C, in the presence of a soluble catalyst based on magnesium formate... 

The affinity for oxygen of the metal involved determines whether reactions of type I or type II occur. Nickel formate produces nickel, magnesium formate produces magnesium oxide. Of special interest to us, however, is the extent to which reactions of type a or b occur, and whether the Ia/Ib or the Ila/IIb ratio is in any way related to the selectivity of the catalytic decomposition of formic acid on the metals and oxides in question. Furthermore it is worth while to investigate whether the stability of the bulk formates (e.g., the decomposition temperature) bears a relation to the catalytic activity of the corresponding metals or oxides. 

Dollimore et al. (141) also investigated the effect of sample container composition on the DTA curve of magnesium formate 2-hydrate. Sample containers constructed from AI, Cu, and Pt metals were compared and discussed. 

Mg(HCOO)2 2 H2O MAGNESIUM FORMATE dil Molecular weight 150.388 lydrate ... 

Formic acid + dolomite calcium formate + magnesium formate + carbon dioxide + water... 

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