Diphosphonate compound and use thereof for stabilization of polyolefins

Diphosphites of formula (IV) having improved resistance to hydrolysis and increased thermal stability, are new: R1, R2, R4, R5, R7, R8, R10 and R11 = H or alkyls CmH2m+1 (m = 1-4); R3, R6, R9, and R12 = as above, aryl or aralkyl; and n = 0-3. More specifically, R1, R2, R4, R5, R7, R8, R10 and R11 = Me; and n = 0. Also claimed are (i) a process for the prepn. of the diphosphites (see PREPARATION below); (ii) a polymer compsn. comprising a polyolefin and the novel diphosphite; and (iii) a polymer compsn. as (ii) also contg. a hindered phenol. The polyolefin is esp. polypropylene; and the hindered phenol is esp. from (from 20 prefd. listed): tetrakis (methylene-3-(3,5-di-t-Bu-4-hydroxyphenyl)propionate)methane; octadecyl-3-(3,5-di-t-Bu-4-hydroxyphenyl) propionate; 1,3,5-tris(3,5-di-t-Bu-4-hydroxybenzyl)isocyanurate); 3,5-di-t-Bu-4-hydroxyhydrocinnamic acid triester with 1,3,5-tris(2-hydroxyethyl)-s-triazine-2,4,6-(1H,3H,5H)trione; 1,1,3-tris(2-methyl-4-hydroxy-5-t-Bu-phenyl)butane; and 1,3,5-trimethyl-2,4,6-tris(3,5-di-di-t-butyl-4-hydroxybenzyl)benzene. Aralkyl phenol(s) (VI) and an aralkylphenol (VII) are heated in a solvent with PCl3 to form an aralkylphenol dichlorophosphite to which is added pentaerythritol. Prefd. aralkylphenol is 2,4-dicumylphenol, and prefd. solvent is from 5-10C alkanes, toluene, xylene and/or chlorinated solvents, pref. contg. a catalytic amt. of tri(m)ethanolamine or tripropylamine. Hydrolyticky stabiln bis(aralkylfenyl)pentaerythritoldifosforitanov slou eniny obecn ho vzorce IV, ve kter m znamenaj : R.sup.1.n., R.sup.2.n., R.sup.4.n., R.sup.5.n., R.sup.7.n., R.sup.8.n., R.sup.10.n. a R.sup.11.n. substituenty nez visle vybran ze skupiny zahrnuj c vod k a alkylov zbytky obsahuj c 1 a 4 atomy uhl ku, R.sub.n.n. .sup.3.n., R.sub.n.n. .sup.6.n., R.sub.n.n. .sup.9.n. a R.sub.n.n. .sup.12.n. jsou nez visle vybr ny ze skupiny zahrnuj c vod k a alkylov zbytky obsahuj c 1 a 4 atomy uhl ku, a tento substituent je um st n v poloze ortho, meta nebo para vzhledem k um st n m stkov methylenov skupiny, a n je 0 a 3. Slou eniny jsou vhodn jako antioxida n aditiva do polyolefin , zejm na do polypropylenu. Tyto difosforitany maj malou t kavost, vysokou teplotu rozkladu a odolnost v i loutnut p°i sm ch n s polyolefinovou z kladn hmotou. V²hodn²m difosforitanem je bis(2,4-dikumylfenyl)pentaerythritoldifosforitan.\ In the present invention there are disclosed hydrolytic stable bis(aralkylphenyl)pentaerythritol diphosphonate compounds of the general for