504-64-3 tricarbon dioxide

THERMAL DECOMPOSITION OF MALONIC ACID IN THE PRESENCE OF P2O5 

Flask a of the apparatus illustrated in Fig. 209 is charged with 20 g. of malonic acid, 40 g. of calcined sand and 200 g. of fresh, xmcaked and well mixed PsOg, The system is evacuated to 0.1 mm.. 

Separation of the CgOg-COg mixture (COg is a product of the side reaction CgH O = CHgCCX)H + COg) is difficult. Therefore, when the solid phase (COg) has disappeared, it is advisable to reduce the bath temperature to —125°C or —130°C for completion of the separation. Fractionation takes about 15 hours (A. Klemenc, loc. cit.). 

The yield of C3O2 is 2.94 g. (22%). Determination of yield C3O3 (alone or mixed with other gases) is passed through a solution of aniline in xylene. The malonanilide formed is virtually Insoluble in xylene and precipitates as colorless crystals, m.p. 223°C. 

Additional preparative method. Thermal decomposition of di-acetyltartaric anhydride (Klemenc et al.). The yield is better, but the C3O3 contains ketene, which cannot be completely separated. 

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Tricarbon dioxide, C3O2, often called carbon suboxide and ponderously referred to in Chemical Abstracts as l,2-propadiene-l,3-dione, is a foul-smelling gas obtained by dehydrating malonic acid, CH2(C02H)2, at... 

The dehydration of malonic acid, H02C-CH2-C02H, produces C302 (known as tricarbon dioxide or carbon suboxide). Draw the structure for C302 and describe the bonding in terms of resonance structures. 

The chromium oxapropadienylidene complex affords dimethyl malonate when oxidized in methanol (77), and the diester is assumed to be produced by addition of the alcohol to the first-formed tricarbon dioxide ... 

Carbon suboxide, C302, contains carbon in the formal oxidation state of +4/3. Because this is lower than its oxidation state in CO or C02, the oxide is called carbon suboxide. It could also be named as tricarbon dioxide. The linear structure of the molecule is... 

Fig. 209. Preparation of tricarbon dioxide from malonic acid, a) one-liter reaction flask b) rubber stoppers, lightly greased o) connectii tube, 10 mm. I.D. d, and 1) traps e) drying tower containing pea-sized, freshly calcined pieces of CaCO 800-mm.-long manometer tube.

Carbon C3 Carbon suboxide —> Tricarbon dioxide C—c 1.277 linear uv... 

When carbon is burned in a sufficiency of air or oxygen, CO2 results but if the supply of oxygen is limited, highly toxic CO is the major combustion product. Other, higher oxides of carbon can be formed by indirect methods for example, C3O2, carbon suboxide (tricarbon dioxide), results from the dehydration of malonic acid, a three-carbon dicarboxylic acid. The Lewis structures of these three oxides indicate the presence of multiple bonds ... 

Carbon oxides. Write the balanced equation for the complete oxidation of carbon suboxide (tricarbon dioxide). 

Carbon C Carbon suboxide Tricarbon dioxide c—c 1.277 linear UV... 

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