Dioxolane Acetate Route to Chromatography-Free Diacetoxyundecane
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Solution Overview
Problem
The existing process for preparing 2,7-diacetoxyundecane is inefficient, with low yield and high environmental impact due to the use of carcinogenic materials and the difficulty in scaling up silica gel column chromatography, and produces multiple diols that complicate purification.
Innovation Solution
The use of 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate as a novel synthetic intermediate, prepared through a nucleophilic addition reaction with propylene oxide and acetylation, allows for the efficient production of 2,7-diacetoxyundecane via distillation without the need for column chromatography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If silica gel column chromatography is used to separate the three types of diols, then purification precision is improved, but device complexity and ease of manufacture deteriorate due to difficulty in scaling up to industrial scale
Solution Approach 1:
The patent extracts the problematic purification step (silica gel column chromatography) by designing a synthesis route that produces a single diol isomer (2,7-undecanediol) with high selectivity, eliminating the need for separation. This is achieved by using a specifically designed Grignard reagent and reaction conditions that favor the formation of the desired isomer exclusively.
Solution Approach 2:
The patent segments the synthesis process into controlled stages where the first step (Grignard reaction) is optimized to produce only the desired diol isomer, separating the synthesis function from the purification function. This segmentation allows the purification step to be eliminated entirely, resolving the contradiction between precision and manufacturability.
2Productivity
If acetaldehyde is used in the first step, then the synthesis process can proceed, but object-affected harmful factors worsen due to carcinogenicity and sick building syndrome
Solution Approach 1:
The patent replaces the harmful acetaldehyde reagent with a safer alternative that achieves the same synthetic objective. The new reagent system maintains productivity while eliminating the carcinogenic and sick building syndrome-causing properties of acetaldehyde, effectively converting a harmful process into a beneficial one.
3Adaptability or versatility
If three types of diols are produced in the first step, then the reaction is more robust, but manufacturing precision deteriorates due to the need for separation
Solution Approach 1:
The patent applies local quality by designing the reaction conditions and reagent structure to achieve high selectivity for a specific diol isomer at the molecular level. The Grignard reagent and reaction parameters are optimized to ensure that only the desired 2,7-undecanediol is formed, giving the reaction mixture uniform quality that eliminates the need for separation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method achieves a high yield of 2,7-diacetoxyundecane with a lower environmental impact, enabling economic and scalable production by eliminating the need for complex purification steps.
Implementation Method 1
nucleophilic addition reaction with propylene oxide
Implementation Method 2
acetylation
Implementation Method 3
eliminating a ketal from 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate
Implementation Method 4
subjecting the aforesaid 10-acetoxy-5-undecanone (5) to a reduction reaction
Implementation Method 5
subjecting the aforesaid 10-acetoxy-5-undecanol (6) to an acetylation reaction
Data Source
AI summary
The present invention provides 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate of the following formula (1). The present invention further provides the aforesaid 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate (1), the process comprising the step of subjecting an organic magnesium compound (2) of the following general formula (2), wherein X1 represents a halogen atom or a 3-(2-butyl-1,3-dioxolan-2-yl)propyl group, to a nucleophilic addition reaction with propylene oxide of the following formula (3) and then reacting with an acetylating agent of the following general formula (4), wherein X2 represents a halogen atom, an acetoxy group, a methoxy group, or an ethoxy group, to form 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate (1).