Example 1 Preparation of 2,3-pentanedione on a Laboratory Scale Preparation of the metering:
100 g and 84 g of hydroxyacetone paraldehyde are mixed. Carrying • guidance of the reaction:
27 g of concentrated hydrochloric acid, 33 g of water and 2.5 g of tetrabutylammonium bromide solution., 50 wt .-% in water, are combined and heated to 50 ° C. At this temperature the metering mixture (temperature metering mixture: 19-21 ° C) were added within 7 hours.
Then a further 38 g water are added to the reaction mixture and a mixture which consists of water and 2,3-pentanedione substantially distilled off at atmospheric pressure. Subsequently, the phases are separated. This gives 125 g • old 2,3-pentanedione, 92 wt .-% pure according to gas chromatogram. This corresponds to a yield of 85% of the starting material used in deficit.
Example 2 Preparation of 2,3-pentanedione on the industrial scale production of the metering:
150 kg and 126 kg hydroxyacetone paraldehyde are mixed. Carrying • guidance of the reaction:
40 kg of concentrated hydrochloric acid, 50 kg of water and 4 kg of tetrabutylammonium bromide solution., 50 wt .-% in water, are successively in the reactor GEF • filled and heated to 50 ° C. At this temperature the metering mixture (temperature metering mixture: 10 ° C.) is metered within 10 hours.
A further 60 kg of water are added to the reaction mixture and a water / 2,3-pentanedione mixture is distilled off at atmospheric pressure. Subsequently, the phases are separated. This gives old • 174 kg of 2,3-pentanedione, 94 wt .-% pure according to gas chromatogram. This corresponds to a yield of 81% of the starting material used in deficit，

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2樓: Originally posted by John126 at 2015-12-15 09:33:45
Example 1 Preparation of 2,3-pentanedione on a Laboratory Scale Preparation of the metering:
100 g and 84 g of hydroxyacetone paraldehyde are mixed. Carrying • guidance of the reaction:
27 g  ...

are combined and heated to 50 ° C. At this temperature the metering mixture (temperature metering mixture: 19-21 ° C) were added within 7 hours.
大師--是在50 ° C保溫反應(yīng)7小時(shí)吧？計(jì)量混合時(shí)候19-21 ° C?是這意思吧？

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3樓: Originally posted by wu_bing at 2015-12-15 09:58:40
are combined and heated to 50 ° C. At this temperature the metering mixture (temperature metering mixture: 19-21 ° C) were added within 7 hours.
大師--是在50 ° C保溫反應(yīng)7小時(shí)吧？計(jì)量混合時(shí)候19-2 ...

上文中"the metering mixture"應(yīng)該是指100 g and 84 g of hydroxyacetone paraldehyde are mixed，這兩個(gè)物質(zhì)在19-21℃混合。將此混合物慢慢加到預(yù)先加熱至50℃的混合物中（27 g of concentrated hydrochloric acid, 33 g of water and 2.5 g of tetrabutylammonium bromide solution., 50 wt .-% in water, are combined ），滴加時(shí)間7小時(shí)

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4樓: Originally posted by John126 at 2015-12-17 09:59:37
上文中"the metering mixture"應(yīng)該是指100 g and 84 g of hydroxyacetone paraldehyde are mixed，這兩個(gè)物質(zhì)在19-21℃混合。將此混合物慢慢加到預(yù)先加熱至50℃的混合物中（27 g of concentrated hydroc ...