DELAYED-ACTION ACCELERATORS* By W. J. S. NAUNTON, W. BAIRD, and H. M. BUNBURY 'l'licre is little tloitbt t.li:it tlic iliscovcry of orpiiic nccclcrntors of vulcnnisntion was mndc ninrc or less siiiiultnncously in two parts of t,lic \vorltl nntl as tlic rcsiilt of two entirely different invcst,igntions iicit.hcr of wliich hnd ns its tiirgct tlic discovcry of iiccclerntors. In t,lic Uiiitctl Stiitcs it is rccordcd by Ocnslngcr, \rho was :i\vnrdcd tlic l'crkin Jlctlnl in 1032 for t.his work, thnt lic was looking for n cornpouiiding iiigrctliciit \vIiicli \voultl impnrt to nilher goods niiidc froni thc dicnpcr gmdcs of riil)bcr t lie superior wcnring qii:ilit,ies thcu obtniiietl only froin fine Piirii. To liis nst,oiiisIiniciit tlicsc orgiinic subst.iiiiccs not only iinprovcd low-grntlo riilhcrs, but brolight :il)out, n coiisiilcrnlilc iniprovciiicnt iii thc goods iiintlc from tlic Iicst gr;iilcs of rubber, iitid further innilc possilh n considcriil)lc rcduct,ioii iii tlic t h e of curc. I n Gcrinnny c1iciiiist.s were sciirching for tlic act,ivc principlc which rciitlercd rulhcr C0~i~p;iriit~ivcl~ stiilh to ositlnt.ion. Syiitlictic rulhcr and n:ttural rubber from wliicli t.lic nitrogenous sitbstniiccs lii~tl bccn cstrncteil were unstiil)lc. Prom tlicsc facts i t wns n simple stcp to try organic bnses iis stii1)iliscrs of both synthctic nntl raw rubber, and it wis tlicu found.tlint tiicy not only protcctcd tlic rulhcr cigiiinst osidntion, but nlso :iccclt!riitcd t.lic vulriinisiition of tlic rubbcr to which !l'hcrc is, ho\vcvcr, little doubt tliiit uccclcriitors wcrc iiscd in fiiotory production in tlic United Stiitcs for sonic yciirs bcforc t hcy ~vcrc gciiernlly cniployctl in Europc. Proin this period up to tlic present tiinc, iidriiiiccs in t lie chemistry of nccclcrittors liiivc bccn rnntlc vcry In rgcly by subniitting tlic iiccclcriitor in gciicriil usc tit thc timc to furtlicr c1ieniic;il trcntnicnt. Tlic ciirly trccclcrntors, nninely, niiilinc iiiitl siinilnr iiroiniitic iiiiiino-compounds, wcrc obviously destined to a short life bccniisc of tlicir cstrcmc tosicity, with tlic result tliat siniplc dcriviitivcs of iiiiiliiic in wliicli t.lic tosic iinuuo-group lind liecn " stopped " by soinc siniplc clieinicnl rcnction such ns t,rciit,nicnt with ciirboii tlisiilpliidc wcrc tlic nest stage of dcvclopmcnt. Tlic t hioureiis Iiud u coiiipiiriitivcly long innings and, iiccortliiig to Ocnslngcr, rciiclicd LL consiiniption of sonictliing likc 2000 tons pcr i i n i i i i ~i i . Tlicy Iiiid, Iiowcvcr, one scrious defect, uutl that wiis 11 qnick " kick-off " in spitc of tlic fiict tliiit t h y wcre rc;rlly slow iiccclcriitors. At nbout this time, uttcmpts \vcro mnclc Iiy tlircc scliools of workcrs, ntiincly 13cclford and his colluboriitors in tlic Stntcs, Twiss niid liis collcrig~ies in JZnglnntl, iiiitl they llild bccn ntldcd. * Ilcnd Iiofuro tho 1.o11d~11i Swlioii 011 Alnr. 5, lO:l4.
13riini iind his co-workers in Italy, to itt,tnck the problcin of tlic nicclinnisiii of uccclcrntor action in n fundnmentnl way. Obviously, one of tlic first rcnctioiis to I)c studied