CO2 as a mild oxidant hydrocarbon dehydrogenation

An innovative technology is the use of CO2 as a mild oxidant under controlled conditions. This CO2-based process operates at much lower temperature than those thermal processes currently in use, while also being more selective. Such an approach can be applied to great environmental benefit

The fixation of CO2 into natural minerals rich in basic oxides such as CaO or MgO is a methodology for perennial disposal of CO2 (see Chapter 16). Basic minerals are very abundant as components of the Earth's crust, and can be extracted, milled and used for fixing CO2 (Zevenhoven and Kavaliauskaite, 2003). In order for this process to have an appreciable rate, it must be carried out in an aqueous medium. The overall process implies the mining, milling, dissolution and reaction of the minerals with a total energy and chemical

Table 7.2. Energy of formation of some chemicals relevant to C02 chemistry.

Compound

-110.53

-393.51

-413.26

-675.23

-634.92

-241.83 -1207.6 (calcite) -1207.8 (aragonite) -219.1 89 116.6 108.9 135.1 -108.6

197.7

213.8

-1129.1 1128.2

38.1

91.7

Compound

CHqCNO -92

(l)methylisocyanate

HOCH2CH2OH (I) -455.3 163.2

(g) -47.5 36.3 283.8 CH2CH-CH (g)cyclopropene 2 77.1 C3H6(I) 1.7 propene (g) 20 CH2CH2CH2 (g)cyclopropane 53.3

ethenecarbonate 586.30

CH3CHCH20 (I) -122.6

C4H402 (I) diketene -233.1

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CO CO

CO CO O CO

CO CN CN CO

CO LO

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cost that is too high for any practical application, unless some other benefits come in support of the technique such as when car-bonation is used for the remediation of sites.

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