Ester synthesis using heterogeneous au/tio2 catalyst
A technology of catalysts and mixtures, applied in the fields of metal/metal oxide/metal hydroxide catalysts, physical/chemical process catalysts, preparation of organic compounds, etc., can solve the problems of complex separation
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example 1
[0037] Example 1: O 2 oxidizing agent for the reaction
[0038] 80g 2-ethylhexanal, 50g methanol, 3g 1 wt% Au / TiO 2 (grinding), 1 g of 50 wt% NaOH in water was added to a 300 mL nominal Hastelloy autoclave. The reaction temperature was maintained at at least 40°C. The back-pressure was maintained at 100 psig while flowing 8 vol% O at a flow rate of 2,000 sccm 2 Balance N 2 , while stirring at 1500 RPM.
[0039] o 2 existence (from N 2 8% O in 2 Oxygen atoms generated in the mixture of ) oxidize the aldehyde to the acid in the solution phase. However, for the side reaction to generate 2EH-methyl ester, which accepts the released H as an oxidant 2 , forming H 2 O, resulting in the reaction of a significant amount of 2-ethylhexanal to form 2-ethylhexanoic acid, with approximately 5% of the 2-ethylhexanal forming the desired methyl 2-ethylhexanoate product. Table 1 shows the level of methyl 2-ethylhexanoate formed as a function of reaction time as determined by gas ch...
example 2
[0042] Example 2: 2-Ethylhexylenal as an oxidizing agent for a reaction
[0043] 10g 2-ethylhexanal, 10g 2-ethylhexylenal, 50g methanol, 3g 1 wt% Au / TiO 2 (grinding), 0.65 g of 50% by weight NaOH in water was added to a 150 mL titanium autoclave. The reaction temperature was maintained at 150°C, and the reactor was filled with N 2 Purge, then auto pressurize to about 210 psig while stirring.
[0044] Half of the starting 2-ethylhexanal reacts to form the desired methyl 2-ethylhexanoate. Some 2-ethylhexanal was hydrogenated to 2-ethylhexanol. GC results are shown in Table 2, using elution times of known substances. Species formation was subsequently confirmed by GS / MS.
[0045] Table 2: Species % as a function of time
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[0047]
[0048] This example shows 2-ethylhexylenal as an oxidizing agent (H 2 receptors) to drive responses. With milder oxidizing agents, aldehydes are not oxidized to carboxylic acids and accept H 2 The enal becomes an aldehyde specie...
example 3
[0055] Example 3: Direct coupling between 2-ethylhexylenal, 2-ethylhexanal and triethylene glycol
[0056] 20.2g 2-ethylhexylenal, 20.5g 2-ethylhexanal, 6g triethylene glycol, 2g 1 wt% Au / TiO 2 (ground) and 0.38 g of 50% by weight aqueous NaOH were added to a 100 mL self-sealing autoclave. The reaction temperature was maintained at 185°C, and the reactor was filled with N 2 Purge, then auto pressurize to about 300 psig while stirring at 1000 rpm. Samples were taken after every 60 minutes for a total reaction time of 6 hours. Traces of triethylene glycol 2-ethylhexanoic acid monoester (0.4% by weight) were detected by gas chromatography (GC). 2-Ethylhexanol and 2-ethylhexanoic acid were also detected in the mixture. Triethylene glycol 2-ethylhexanoic acid diester was not detected.
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