formaldehyde - Sciencemadness Dot Org

35S
FORMALDEHYDE
An entirely different type of accelerator, Tvhich has proved of considerable
value is obtained by Zimmerman J s process 34 inching renusdng commercial
formaldehyde with mereaptobenzothiazole. The product is a
white crystalline material which melts at 130°C. Although highly active,
it is reported to possess the advantageous property of not accelerating
vulcanization until the rubber mix is heated so that partial vulcanization on
compounding and milling is avoided. Reaction products of secondary
amines? such as morpholine and piperidine, "with mercaptobenzothiazole
and formaldehyde are also claimed to be of value as rubber accelerators 4 .
Antioxidants. .Antioxidants are obtained hy reactions involving formaldehyde
and amines. According to Semoa 59 , tet-raphenylmethylenediamine,
produced by refluxing a mixture of 36 per cent formaldehyde with an excess
of diphenylamine in benzene solution, acts as a good antioxidant when
employed to the extent of 0.1 to 5 per cent in a rubber composition. An
antioxidant is also obtained by the reaction of diphenylaminej formaldehyde,
and cyclohexanol 19 :
CCeHs)s^H -h CH20 4- CeHaOH — * (CflH^sXCHaOCsHi, + H20
Other antioxidants are prepared by reacting formaldehyde with aminoacenaphthene
15 , amino derivatives of diphenylene oxide 7 , and a mixture of
alpha-naphthykmine and the amine derived by the action of ammonia on
beta-beta-dichloroethyl ether 22 .
Synthetic Rubber. Potential applications of formaldehyde in the synthetic-rubber
industry may be found in its use as a raw material for the
synthesis of dienes. Fitsky 9 points out that gamma-chlorobutanol produced
by the action of formaldehyde and hydrogen chloride on propylene
can be converted to butadiene by splitting off hydrogen chloride and
water.
CHs-CHGl-CH£CHsOH —> CH2:CH-CH:CH2 + HC1 + H£0
Isoprene may be obtained in a similar fashion from the addition product
of chloromethanol (formaldehyde plus hydrogen chloride) and isobutylene.
CICHoOH + CH«:C(CH3VCH3 • CH3-C{CH3)CI-CH2-OH£OH
CHs-C(cfc)Cl 0H2.CH2OH » GH2:C(CH3)-CH:CH2 + HC1 4- H30
Other diene syntheses involving the condensation products of formaldehyde
and acetone, etc., are also possible.
As we have previously pointed out (page 131), rubber-like materials
can be obtained by the reaction of formaldehyde with alkali sulfides.
References
l. Bastide, J., French Patent 470,833 (1914)t
3. Bedford, C,W„ (toTbe Goodyear Tire and Rubber Co.), U. S. Patent 1,380,765 (1921).
8. Bradley, C. E., and Cad-well, S- M., {to The Naugatuck Chemical Co.), U. S, Patent 1,444.865 (1923).