Thermal decomposition of calcium propionate
There is a paper (1) where TG-GLC-MS with subsequent XRD analysis of solid products has been utilized for the analysis of evolved gases during the decomposition of calcium propionate at various heating rates. Detected products were $\ce{H2O}$, $\ce{CO2}$, $\ce{C2H5CHO}$, $\ce{C2H5COCH3}$, $\ce{C2H5COC2H5}$, $\ce{CaCO3}$.

The Discussion section of the paper suggests the following mechanism of formation:


  Following the free radical mechanism of Hites and Biemann (2), proposed for 
  the decomposition of the calcium salts of monocarboxylic acids we suggest that the initial stage in the decomposition of calcium propanoate can be represented as: 
  
  $$\ce{Ca(C2H5COO)2 -&gt; CaCO3 + C2H^.5 + C2H5C^.=O,}$$
  
  Combination of the two free radicals results in the formation of the major product, 3-pentanone: 
  
  $$\ce{C2H5C=O + C2H^.5 -&gt; C2H5 - CO - C2H5}$$
  
  The other trace products observed, 2-butanone and propanal, can be accounted for by disproportionation reactions involving the ethyl radical:
  
  $$\ce{C2H^.5 + C2H^.5 -&gt; C3H^.7 + CH^.3}$$
  
  and
  
  $$\ce{C2H^.5 -&gt; C2H5 + H^.}$$
  
  The methyl and hydrogen radicals so produced may react with the large excess of the original propanoyl radicals to give 2-butanone and propanal respectively.
  
  $$\ce{C2H^.5=O + CH^.3 -&gt; C2H5COCH3}$$
  
  and
  
  $$\ce{C2H5C=O + H -&gt; C2H5CHO}$$
  
  The $\ce{C3H7}$ may combine with any of the other radicals or may disproportionate. In any event there was no evidence for compounds larger than 3-propanone. However on close examination of the GC curves there were indications of a very small peak before that due to $\ce{CO2}$ which could be attributed to low molecular weight alkanes and alkenes. 


(1) Barnes, P. A.; Stephenson, G.; Warrington, S. B. Journal of Thermal Analysis 1982, 25 (2), 299–311. DOI: 10.1007/BF01912955

(2) Hites, R. A.; Biemann, K. J. Am. Chem. Soc. 1972, 94 (16), 5772–5777. DOI: 10.1021/ja00771a039