Journal of the Korean Industrial and Engineering Chemistry, Vol.6, No.2, 243-249, April, 1995
5-Methyl-4-Imidazolecarboxylic Acid Ester 연속합성 반응의 특성 및 공정개발 연구
A Study on the Development of Continuous Process for the Production of 5-Methyl-4-Imidazole-Carboxylic Acid Ester
초록
Ethylacetoacetate 로부터 중간 생성물인 α-acetyl-α-hydroxy iminoacetic acid, α, β-dioxobutylic acid를 거쳐 생성되는 5-methyl-4-imidazolecarboxylic acid ester의 연속반응공정 개발을 위하여 세 경우의 연속 반응기 schemes : 1) Annular Flow Reactor 2) Continuous Flow Stirred Tank Reactor (CFSTR) 3) Heat Exchange Loop/plug Flow Reactor에 따른 반응수율특성, 공정변수 영향 등을 연구하였다. 율속 단계인 uα,β-dioxobutylic acid 생성 반응의 수율을 최대로 높일 수 있는 반응기 scheme은 연속적으로 배열된 2중 열교환 루프를 거쳐 냉각조에 잠겨있는 플러그흐름 반응기를 통과시키는 배열이었으며 이때의 수율은 HCI의 농도에 따라 (6.6∼8.3M) 70∼75%이었다. 또한 반응 체류시간은 1∼1.5hr이었으며 발열반응으로 인한 α,β-dioxobutylic acid의 decomposition이 일어나는 온도범위는 12∼15℃ 이었다. 2중 열교환 루프에서의 총괄 전열 계수는 25Btu/hr-ft2-。F이었고 막(film) 전열계수는 약 40Btu/hr-ft2-。F로 추정되었다. 이러한 연속 반응기 scheme은 반응수율의 감소없이 2중 열교환 루프에 허용될 수 있는 최적의 공정변수 (온도, HCI 주입속도, 반응체류시간 등)만 결정되면 상업화 공정 Scale-up이 충분히 가능할 것으로 판단된다.
Three continuous reactor schemes : 1)Annular Flow Reactor, 2)Continuous Flow Stirred Tank Reactor(CFSTR), 3) Heat Exchange Loop/Plug Flow Reactor, were tested under the formation of α, β-dioxobutylic acid, which is the rate-controlled step. The reactor scheme which performed best in terms of α, β-dioxobutylic acid yield consists of a heat exchange loop containing two double-pipe exchangers in series, followed by a plug flow reactor immersed in a coolant bath. The rate of formation of α, β-dioxobutylic acid was found to be a function of α-acetyl-α-hydroxyiminoacetic acid and HCI concentration. The decomposition of α, β-dioxobutylic acid was found to occur in the range of process temperature, 12∼15℃. Overall heat transfer coefficient based on inside area and the film coefficient was 25 and 40 Btu/hr-ft2-℉, respectively. The reactor scheme which was developed in this study is scalable to the commercial, size, with the optimal determination of process variables.
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