On July 2, 2008, Kotachi, Shinji; Fukuda, Kazuyuki published a patent.Name: 2-Methyl-2-propylpropane-1,3-diol The title of the patent was Preparation and process for purifying acetal compounds in presence of antioxidants for perfumes. And the patent contained the following:
The present invention relates to (i) a process for purifying an acetal compound having a sweet floral scent and a process for producing the acetal compound, which are inhibited from generating off-odor even when subjecting the acetal compound to distillation under a low vacuum and at a high temperature; and (ii) a perfume composition containing the acetal compound In accordance with the present invention, there is provided a process for purifying an acetal compound represented by the general formula (I; R1 = H, Me, Et; R2 = Pr, iso-Pr; R3 = H, Pr, iso-Pr), the process including the step of subjecting a raw material containing the acetal compound to distillation at a temperature of 80 to 170° in the presence of an antioxidant. Thus, reaction of 396 g of 2-methyl-2-propyl-1,3-propanediol with 300 g of 2-methylpentanal in presence of 444 g of Et formate resulted in 636 g of a raw material containing 2-(1-methylbutyl)-5-methyl-5-propyl-1,3-dioxane. The raw material (100 g) was mixed with 0.1 g of 2,2′-methylenebis(4-ethyl-6-tert-butylphenol) as an antioxidant, and the mixture was subjected to distillation under such a condition that a main distillate was distilled off under a pressure of 5 to 7 kPa and at a temperature of 138 to 143°, thereby 97 g of a fraction composed of 2-(1-methylbutyl)-5-methyl-5-propyl-1,3-dioxane (purity 98.4%). As a result of analyzing the thus obtained fraction by gas chromatog., it was confirmed that no 2,2-dimethylpentyl-2-methylpentanoate as a byproduct was detected, and no fruity green off-odor was sensed. The experimental process involved the reaction of 2-Methyl-2-propylpropane-1,3-diol(cas: 78-26-2).Name: 2-Methyl-2-propylpropane-1,3-diol
The Article related to acetal compound preparation purification distillation antioxidant perfume, Essential Oils and Cosmetics: Fragrance Preparations and other aspects.Name: 2-Methyl-2-propylpropane-1,3-diol
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