Hauv qab no yog kev tsim cov PAPI.
PAPI (nyoos MDI) yog tsim tib yam li MDI tsuas yog qhov sib piv ntawm tus nqi aniline mus rau hydrochloric acid tsawg dua. Tus synthesis ntawm PAPI thiab MDI zoo li yog nyob hauv ob kauj ruam. Ua ntej, cov tshuaj aniline thiab formaldehyde (formalin) yog condensed rau hauv polyamine kom sib xyaw uas muaj ib cov nqi ntawm cov diamine nyob rau hauv qhov kev txiav txim ntawm Lewis acid, thiab tom qab ntawd ces cov khoom siv rau cov kab mob polyamine raug phosgenation cov tshuaj kom tau PAPI. Nyob rau hauv cov synthesis ntawm polyamine tebchaw, cov ntsiab lus ntawm diamine tswj tau li 50%. Feem ntau, nws yuav ua tau tiav los ntawm kev kho qhov sib piv ntawm cov nyiaj ntawm cov khoom siv ntawm ob yam khoom raw ntawm aniline thiab formaldehyde, uas yog, tus nqi ntawm cov khoom. Nws tau raug experimentally txiav txim tias thaum tus piv ntawm aniline rau formaldehyde yog 1:75, li 50% ntawm cov diamine hauv synthesized polyamine compound yog tam sim no. Vim li no, cov khoom siv pab pawg faib khoom faib, feem ntau qhov piv ntawm tus nqi aniline thiab formaldehyde yog 1.6 mus rau 2. Qhov ntau ntawm O hloov, lwm cov kev khiav hauj lwm rau kev kho mob rau polyamine synthesis zoo li cov ntawm MDA. Lub sam thiaj yuav tsum muaj cov txheej txheem ntawm MDI thiab PAPI yuav tsum muaj cov khoom siv rau cov khoom uas muaj 60% mus rau 75% diamine, thiab lub ntsiab tseem ceeb los ntawm kev hloov tus nqi ntawm cov khoom siv aniline thiab formaldehyde cov khoom siv. Thaum tus piv ntawm qhov aniline / formaldehyde quav tshuaj yog 4 / 1.4, synthesized polyamine muaj li 75% ntawm diamine compound. Feem ntau, cov txheej txheem ntawm kev tsim cov tshuaj MDI thiab PAPI yog saws.