Semiconductor TiO2 photocatalyst of surface modified cocatalyst, preparing method and uses thereof

Abstract

The invention relates to the technical field of selective photocatalytic oxidation synthesis, which more particularly relates to a semiconductor TiO2 photocatalyst modified with promoter on the surface and the corresponding preparation method, as well as the catalyst application on the selective oxidation of primary alcohol or secondary alcohol to Aldehyde or Ketone. The invention is designed to perform chemical treatment on the TiO2 surface to convert the TiO2 into organic nitro-oxy radical which can highly selectively react with the primary or secondary alcohol to obtain the corresponding aldehyde or ketone as for the selectivity of stereo-hindrance, through an in-situ conversion of photo-excited holes. The selective conversion rate to any hydrin by the catalyst in the invention can achieve up to 99%, while commonly the conversion rate is over 90%, particular to the aromatic alcohol e.g. benzyl alcohol of over 99% of selectivity; both the catalyst and promoter can be reused for times through simple filtration, have long life without carbon deposition; the conditions of both preparation and reaction are mild.

Description

Technical field [0001] The invention relates to the technical field of photocatalytic selective oxidation synthesis, in particular to semiconductor TiO with a surface modification promoter 2 Photocatalyst and preparation method thereof, as well as using the catalyst to selectively oxidize primary and secondary alcohols to prepare aldehydes or ketones. Background technique [0002] Energy and environment have become the biggest focus of today's sustainable development. How to use renewable energy such as clean solar energy to replace fossil energy has always been the highest state and biggest problem in theoretical research and industrialization. As a traditional industrialized project-the reaction of alcohol oxidation to aldehyde, due to the requirements of selectivity and product separation, the industry has always used halogen-containing oxidants such as hypochlorous acid, iodooxybenzene and other polluting by-product oxidants, or use high manganese Heavy metal oxyacids such as...

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Problems solved by technology

However, the selective oxidation of organic matter is seldom used, because the combined action of hydroxyl radicals and molecular oxygen in the aqueous phase leads to the mineralization of most of the organic matter into CO 2 and H 2 O, but can not get the target product of main aldehyde or ketone

"Journal of the American Chemical Society" on page 8304 of volume 127 in 2005 "Titanium-silicon molecular sieves with size-effect-related catalytic conversion" (Yasuhiro Shiraishi, * NaoyaSaito, and Takayuki Hirai Titanosilicate Molecular Sieve for Size-Screening Photocatalytic Conversion. J.AM.CHEM.SOC.2005, 127, 8304~8306) have reported that TiO 2 Structural modification, adding TiO in the cavity of the molecular sieve 2 , capable of hydroxylating phenolic compounds with the help of channel selectivity, also reported on bare TiO 2 On, by controlling the reaction time period, the reactant is converted into CO 2 and H 2 O to intercept the target product before, such as the article published in "Chemical Bulletin" on page 2804 in 2006 "Using TiO 2 Synthesis of a coumarin compound from phenanthrene by a photocatalytic reaction" (Suguru Higashida, Aiko Harada, Rikako Kawakatsu, Noriko Fujiwara and Michio Matsumura Synthesis of a coumarin compound from phenanthrene by a TiO 2 -photocatalyzedreaction.Chem.Commun.2006, 2804~2806), these reactions can use clean solar energy, and air oxygen is the oxidant to quickly start the photocatalytic reaction, but the defects are also obvious, the former is due to the great limitation of the channel mass transfer , especially at low temperature, the space velocity of the reaction is too low, and the latter has poor selectivity due to uncontrollable simultaneous side reactions

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