- Method for preparing ligustral
-
The invention provides a method for preparing ligustral. The method comprises the following steps: preparing 2,4,4,6-tetramethyl-1,3-dioxane, preparing 2-methyl-1,3-pentadiene, and synthesizing the ligustral. The whole reaction process is gentle in condition, nearly free of side effect, short in time and low in energy consumption, the total yield of the ligustral of the three steps of reaction is greater than 87%; the 2,4,4,6-tetramethyl-1,3-dioxane is prepared in a first step, and the yield is greater than 98%; the 2-methyl-1,3-pentadiene is prepared in a second step, and the yield is greater than 96%; the ligustral is synthesized in a third step, and the yield is greater than 94%; small molecules such as isobutene and acetaldehyde which are low in price and easy to obtain are adopted as raw materials, a process route for preparing the 2-methyl-1,3-pentadiene is innovated, steps such as condensation and dehydration which are high in cost and low in yield in a conventional process are avoided, and the cost of the method is reduced by about 40% when being compared with that of a conventional process.
- -
-
Paragraph 0008; 0028; 0032; 0038; 0041; 0045; 0047
(2017/08/29)
-
- Production process of ligustral
-
The invention discloses a production process of ligustral which is widely applied to detergents, fabric softeners, body wash and other daily chemical blending perfume in American Procter and Gamble Company, International Flavors and Fragrances and European Givaudan Company. The process comprises procedures described in brief as follows: (1) a dehydration reaction; (2) a primary addition reaction.
- -
-
Paragraph 0008
(2017/07/19)
-
- Method for preparing female loyal aldehyde
-
The invention discloses a ligustral preparation method, which comprises the following steps: 1) adding acrolein to a reaction container filled with 2-methyl-1,3-pentadiene, wherein a reaction temperature is controlled to 45-75 DEG C and a pressure in the reaction container is controlled to 0.10-0.50 MPa during addition; 2) after completing the material adding, aging for 2-6 h at a temperature of 70-100 DEG C; 3) after completing the aging, cooling to a temperature of 30-40 DEG C, slowly heating to a temperature of 85-100 DEG C under -0.070 to -0.085 MPa, and distilling to obtain a heavy distillate ligustral crude product; 4) washing the ligustral crude product with an alkaline solution, and carrying out water washing to achieve a neutral state; and 5) finally carrying out rectification under the protection of inert gas, and collecting a distillate with a boiling point of 78-83 DEG C/10 mmHg to obtain the ligustral finished product. The ligustral preparation method has characteristics of simple preparation process, high product yield, low production cost, and easy industrial production.
- -
-
Sheet 0023-0029
(2017/02/09)
-
- Preparation of imidazolidin-4-ones and their evaluation as hydrolytically cleavable precursors for the slow release of bioactive volatile carbonyl derivatives
-
Imidazolidin-4-ones are suitable in practical applications as hydrolytically cleavable precursors for the controlled release of fragrant aldehydes and ketones. The corresponding profragrances were prepared by treating aliphatic carbonyl compounds with commercially available amino acid amines in the presence of a base to yield mixtures of diastereomers. The two diastereomers isolated from the reaction of glycinamide hydrochloride with (-)-menthone were separated by column chromatography. The absolute stereochemistry of the isomers was determined by NMR spectroscopy and confirmed by X-ray single crystal structure analysis. Under acidic conditions and in protic solvents, the two diastereomers slowly isomerized without releasing the ketone. The hydrolysis of the precursors was investigated by solvent extraction from buffered aqueous solutions and a cationic surfactant emulsion, as well as by dynamic headspace analysis after deposition onto a cotton surface. Generally, ketones were shown to be more readily released than aldehydes. Increasing the size of the substituents at C-5 decreased the rate of hydrolysis in solution and on the cotton surface. Glycinamide-based imidazolidin-4-ones were more efficient than the corresponding oxazolidin-4-ones or oxazolidines. Neither the release rates in solution, nor the hydrophobicity of the precursor structure (which influences deposition), nor the combination of these two parameters allowed easily predicting the performance of the delivery systems in application. Copyright
- Trachsel, Alain,Buchs, Barbara,Godin, Guillaume,Crochet, Aurelien,Fromm, Katharina M.,Herrmann, Andreas
-
supporting information; experimental part
p. 2837 - 2854
(2012/07/03)
-
- Controlled light-induced release of volatile aldehydes and ketones by photofragmentation of 2-oxo-(2-phenyl)acetates
-
The light-induced controlled release of fragrances from photolabile 2-oxo-(2-phenyl)acetates via Norrish Type II photofragmentation was evaluated by irradiation of the precursors in different solvents and on cotton in a typical fabric softener application. The desired photooxidation was found to work efficiently in water-based systems, and it tolerates the presence of oxygen. The formation of a certain amount of alcohol besides the desired aldehyde or ketone was attributed to further reaction of the photochemically released carbonyl compound, rather than to ester hydrolysis in an aqueous environment. Schweizerische Chemische Gesellschaft.
- Levrand, Barbara,Herrmann, Andreas
-
p. 661 - 664
(2008/03/11)
-
- Precursors for fragrant ketones and fragrant aldehydes
-
The present invention refers to fragrance precursors of formula I for a fragrant ketone of formula II and one or more fragrant aldehydes or ketones of formula III and IV, These fragrance precursors are useful in perfumery, especially in the fine and functional perfumery.
- -
-
-