High pressure distillation, tetrahydrofuran

Reppe s work also resulted in the high pressure route which was estabUshed by BASF at Ludwigshafen in 1956. In this process, acetylene, carbon monoxide, water, and a nickel catalyst react at about 200°C and 13.9 MPa (2016 psi) to give acryUc acid. Safety problems caused by handling of acetylene are alleviated by the use of tetrahydrofuran as an inert solvent. In this process, the catalyst is a mixture of nickel bromide with a cupric bromide promotor. The hquid reactor effluent is degassed and extracted. The acryUc acid is obtained by distillation of the extract and subsequendy esterified to the desked acryhc ester. The BASF process gives acryhc acid, whereas the Rohm and Haas process provides the esters dkecdy. 

Phenyl-7-azabicyclo[U,l,0]heptane 20G of phenyl azide and 20g of cyclohexene in 50ml of tetrahydrofuran were refluxed for 8 hours. Triazoline was obtained by distilling off the solvent and the unreacted components. 3G of triazoline was dissolved in 100ml of benzene and irradiated with a 100 watts high pressure mercury lamp for 5 hours. After irradiation, benzene was distilled off. 7-Phenyl-7-azabicyclo[U,l,0]heptane was obtained as the residue. 

Tetrahydrofuran (THF), either distilled reagent grade or high-pressure liquid chromatography (HPLC) grade (see Note 1)... 

The Geminox process oxidizes n-butane in air over a vanadium-phosphorous oxide catalyst in a fluid-bed reactor to maleic anhydride, which is then quenched to maleic acid by absorbing it into water. This highly acidic stream is then pumped to two high-pressure fixed-bed hydrogenation reactors containing carbon-supported catalysts to convert maleic acid to BDO. The major product of reaction, a mixture of 1,4-butanediol, tetrahydrofuran (THF), and y-butyrolactone, is then separated by fractional distillation. The yield of... 

A microporous polyethyleneterephthalate (PETP) membrane (30 pm thick, 0.2 pm micropores) was used in the experiments. The membrane was immersed into tetrahydrofurane (THE) and the pressure in the beaker was reduced in order to remove air from the micropores and to allow their filling with the solvent. The membrane was then dipped into a saturated solution of DPB in THE containing different amounts of poly(vinyl chloride) (PVC), (high molecular weight). After 2 hour soaking the membrane was dried at room temperature. Before the use, the membrane was kept overnight in distilled water. 

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