Trioxane prodn. from form-aldehyde gas using vanadyl hydrogen phosphate

摘要

In the prodn. of trioxane (I) from HCHO in the gas phase, vanadyl hydrogen phosphate hemihydrate (II) is used as catalyst.Pref. (II) is in water-depleted form and is activated with steam (24 h to 14 days at 100-200 deg.C). Reaction is carried out with dry HCHO at 80-150, esp. 100-120 deg.C and 0.5-5, esp. 0.5-2 bar, opt. with addn. of a carrier gas (N2). In an example, the selectivity has 1 (no by-prods. formed) if 0.43 mole/h HCHO + 1.8 mole/h N2 were passed through a reactor contg. 82 g (II) pellets at 80 deg. C; the conversion was 22.1%, i.e. 62.8% of the equilibrium conversion, and throughput 35.3 kg/cu.m.h.