Preparation of Methylenediphenyldiurethanes by the Acid Rearrangement of [(Ethoxycarbonyl)phenylaminomethyl] phenylcarbamic Acid Ethyl Esters

[(에톡시카르보닐)페닐아미노메틸]페닐카르바민산 에틸에스테르의 산 재배열에 의한 메틸렌 디페닐디우레탄의 제조

The rearrangement of [(ethoxycarbonyl)phenylaminomethyl]phenylcarbamic acid ethyl esters(N-benzyl compounds) to methylenediphenyldiurethanes(MDU) in sulfuric acid, sulfuric acid-absolute ethanol solvent system, and sulfuric acid-nitrobenzene solvent system, and boron trifluoride at $90^{\circ}C$ was studied. The production of MDU was the highest in sulfuric acid-nitrobenzene system giving 64% MDU yield, of which 58% was 4,4'-MDU. The simultaneous condensation of EPC and formaldehyde and rearrangement to MDU were studied in the presence of different amounts of sulfuric acid, trifluoroacetic acid, and boron trifluoride at $70^{\circ}C$. Though 17mmol of sulfuric acid with 30mmol of EPC produced the highest MDU, the MDU yield was much lower than that from separate condensation and rearrangement reaction.

Ethylphenylcarbamate(EPC)와 포름알데히드를 산 촉매 하에서 축합하여 생성한[(ethoxycarbonyl)phenylaminomethyl phenylcarbamic acid ethyl esters(N-benzyl화합물)를 $90^{\circ}C$, 황산, 황산-무수에탄올 용매계, 황산-니트로벤젠 용매계, 3플루오르화 붕소 촉매 하에서 재배열반응에 의해 methylenediphenyldiurethane(MDU)의 합성조건을 검토한 결과 니트로벤젠 용매하에서 반응시킨것이 MDU 생성율이 64%로 가장 높은 생성율을 나타내었고 4,4'-MDU의 생성율도 전체 MDU의 58%를 차지하여 가장 높았다. EPC와 포름알데히드를 $70^{\circ}C$, 몇 가지 다른 양의 황산, 트리플루오르아세트산, 3플루오르화 붕소 촉매 하에서 축합과 재배열반응을 동시에 일으키기 위한 반응조건을 검토한 결과 촉매로서 황산의 양을 EPC 30mmol에 대해서 황산 17mmol을 첨가한 경우가 MDU의 생성율이 가장 높았으나 별도의 재배열 반응을 통한 합성보다 생성율이 낮았다.