Method for preparing ethyl caproate by continuous esterification

Abstract

The invention discloses a method for preparing ethyl caproate by continuous esterification, which comprises the following steps of: mixing caproic acid and ethanol in the mol ratio of 1: (1-1.5), then preheating, esterifying by a fixed bed catalyst layer, then entering an ethanol fractionating tower, extracting 95%(V / V) alcohol obtained at the tower top, using the 95%(V / V) alcohol as a mixture and recycling; discharging the caproic acid and water from the tower bottom, separating out the caproic acid and recycling again; and leading out the total liquid phase from the position above a feed opening in the middle of the tower and naturally layering, wherein the upper layer is the water which reflows into the tower, and the lower layer is an ethyl caproate crude product which is extracted and refined separately. The method has the advantages that the method can operate within a wider esterification range without considering the conversion rate of the caproic acid; the unreacted caproic acid is separated from the water, thereby avoiding the defects of influencing the flavor of the ethyl caproate and reducing the yield caused by blackening and coking of the caproic acid due to heating when in conventional production and recovery; a neutralization washing work procedure is saved, and no neutralizing waste water exists; and the production efficiency is high.

Description

technical field [0001] The invention relates to a method for preparing ethyl caproate through continuous esterification, in particular to a method for continuously and efficiently preparing ethyl caproate. Background technique [0002] Ethyl caproate is the main aroma component of Luzhou-flavor liquor, and its content directly affects the quality of liquor. Because the traditional solid-state brewing method produces liquor, its liquor yield is low, and fragrance substance is few. In recent years, the method commonly used in the production process of new-type liquor is: reduce the alcohol content of edible alcohol, add a part of solid-state distilled liquor, and then blend with the essence containing ethyl caproate. This makes ethyl caproate an indispensable raw material for the production of liquor. The annual use of ethyl caproate in the country is more than 5,000 tons. Therefore, to innovate the production method of ethyl caproate, choose a simple, pollution-free, fast an...

AI Technical Summary

Problems solved by technology

[0004] The above process has the following defects: the esterification rate is low, sulfuric acid produces side reactions, it consumes a lot of energy to separate the reaction water into the vapor phase, the evaporated alcohol is not a finished product and cannot be directly recycled, and the waste water produced by neutralization needs to consume more alkali. Equipment production efficiency is low

[0009] These methods all generally go to focus on improving the rate of esterification, and there are following defects in the use process: increase the molar number of raw material ethanol, the rate of esterification is not much higher if it is improved, and the more the amount of recovery is increased the more Larger, the greater the energy consumption, the greater the loss; changing the catalyst can only increase the esterification rate by a few percentage points, but cannot achieve full conversion, and there is still a separation problem; adding water-absorbing agents to dehydrate in the reaction is time-consuming, energy-consuming, and high-cost