- Method for preparing ethyl maltol from corn cobs with furfuryl alcohol process
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The invention discloses a method for preparing ethyl maltol from corn cobs with a furfuryl alcohol process in the technical field of chemical synthesis. The method comprises the steps as follows: preparing furfural from the corn cobs with a two-step method; generating of furfuryl alcohol from furfural through a reaction: furfural and a platinum-loaded nitrogen-doped graphene material are placed in a reaction device, distilled water is added, hydrogen is introduced, and the mixture reacts at 90-160 DEG C for 4-8 h and furfuryl alcohol is prepared; preparing pyromeconic acid from furfuryl alcohol through chlorination and isomerization reactions; preparing hydroxyethyl maltol through condensation; finally, preparing ethyl maltol through reduction: heating is performed continuously after reaction for distilling off an ethanol aqueous solution, the temperature is increased for distilling off crude ethyl maltol, chloroform is added to the crude ethyl maltol for dissolving the crude ethyl maltol, the solution is cooled to 0 DEG C for recrystallization, crystals are dried, and finished maltol is obtained. Pollution-free, green, environment-friendly and pure food-grade ethyl maltol which is high in yield and produces no wastewater basically is prepared with the preparation method; as the structure of the maltol is similar to that of the ethyl maltol, the preparation method can be general, and all that is required is to adjust other raw materials in the reactions.
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Paragraph 0011; 0012; 0013
(2017/08/28)
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- Maltol and homolog preparation method by means of molecular oxygen oxidation
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The invention provides a maltol and homolog preparation method by means of molecular oxygen oxidation. The method comprises the following steps of charging, a first-stage oxidation reaction, a second-stage oxidation reaction and hydrolysis. According to the first-stage oxidation reaction, alpha-furyl alcohol is used as a raw material, gas with an oxygen content of 15%-85% is used as an oxidizing agent, a heteroatom molecular sieve and basic resin are used as a composite catalyst in a solvent, and an oxidizing ring opening rearrangement reaction is conducted at the temperature of 50-160 DEG C; according to the second-stage oxidation reaction, the temperature drops to 10-40 DEG C, gas with an oxygen content of 90% or above is pumped in, an epoxidation reaction is conducted, and the temperature of the reaction is kept for 0.5-3 h. According to the method, the production yield reaches 50% or above, and the production yield reaches 67% or above in the condition of optimization; the oxidation reaction conducted by using molecular oxygen has the advantages of energy conservation, low cost and environmental protection, and recycling and application of the catalysts are easier to achieve by means of the composite catalyst made from the heteroatom molecular sieve and the basic resin.
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Paragraph 0023-0027; 0053-0057
(2017/09/26)
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- A novel heterocyclic atom exchange reaction with Lawesson's reagent: A one-pot synthesis of dithiomaltol
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A one-pot reaction of maltol with Lawesson's reagent generates dithiomaltol, a thiopyran-4-thione, via an unusual heterocyclic atom exchange (HCAE) reaction; only pyrones with proton or aliphatic substituents undergo the HCAE substitution. The Royal Society of Chemistry 2006.
- Brayton, Daniel,Jacobsen, Faith E.,Cohen, Seth M.,Farmer, Patrick J.
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p. 206 - 208
(2008/02/07)
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- Method of synthesizing gamma pyrones
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Maltol and ethyl maltol can be produced from a haloenone intermediate by reacting the intermediate with acid in a reaction medium comprising an aprotic solvent.
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- Process for the production of isosolanone and solanone, intermediates useful in said process and organoleptic uses of said intermediates
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Described is a novel genus of compounds defined according to the structure: STR1 wherein Z represents hydrogen, MgX and the moiety having the structure: STR2 and X represents chlor, bromo, or iodo; as well as 5-isopropyl-8-methyl-5,8-nonadien-2-one; uses of same as intermediates in a process for producing isosolanone and solanone; and organoleptic uses of 5-isopropyl-8-methyl-5,8-nonadien-2-one and 2,6-dimethyl-5-methylene-1-hepten-4-ol. The novel process of our invention involved the steps of: (i) formation of the compound having the structure: STR3 by means of reacting 3-methyl-2-methylenebutanal with the compound having the structure: STR4 (ii) acid hydrolysis of the resulting compound in order to form 2,6-dimethyl-5-methylene-1-heptene-4-ol; (iii) reaction of 2,6-dimethyl-5-methylene-1-hepten-4-ol with methyl aceto acetate in order to form 2,6-dimethyl-5-methylene-1-hepten-4-yl aceto acetate or, directly, 5-isopropyl-8-methyl-5,8-nonadiene-2-one; (iv) reacting 2,6-dimethyl-5-methylene-1-hepten-4-yl aceto acetate in the presence of an appropriate catalyst to form the 5-isopropyl-8-methyl-5,8-nonadiene-2-one; and (v) isomerizing the 5-isopropyl-8-methyl-5,8-nonadien-2-one in order to form a mixture of solanone and the isosolanone or 5-isopropyl-8-methyl-5,8-nonadiene-2-one.
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- Conversion of Secondary Furfuryl Alcohols and Isomaltol to Maltol and Related γ-Pyrones
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A one-pot synthesis of maltol and ethylmaltol is reported.Treatment of methylfurfuryl alcohol with 2 equiv of halogen affords good yields of 4-halo-6-hydroxy-2-methyl-2H-pyran-3(6H)-ones (8), which need not be isolated and can be converted to maltol by aqueous hydrolysis in the same vessel.A similar sequence employing ethylfurfuryl alcohol yields ethylmaltol.By a related series of reactions, isomaltol (9) can be converted to maltol.
- Weeks, Paul D.,Brennan, Thomas M.,Brannegan, Daniel P.,Kuhla, Donald E.,Elliot, Mark L.,et al.
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p. 1109 - 1113
(2007/10/02)
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- Process for preparing 3-oxy-4H-pyran-4-one derivatives
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A process for preparing a 3-oxy-4H-pyran-4-one derivative which comprises the steps of: 1. epoxidizing a 3-oxo-3,6-dihydro-2H-pyran derivative with a peroxide to obtain a 4,5-epoxy-3-oxotetrahydropyran derivative, and 2. heating the 4,5-epoxy-3-oxotetrahydropyran derivative.
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