Metacyclophane, synthesis thereof, and compositions stabilized thereby

[1.1.1.1.]metacyclophane is a cyclic compound consisting of two alkane bisphenol molecules coupled through their available ortho positions by a methylene moiety. The cyclic compound is initially formed as a dihydrate by reaction of a 2,2'-di-substituted alkane bisphenol such as a 2,2'-di-t.butylated alkane bisphenol with paraformaldehyde at about 170.degree. C. in an aromatic solvent. The dihydrate may be dehydrated under select conditions. The cyclic compound is an excellent antioxidant in mineral filled natural rubber, and in polyolefins, particularly in polypropylene.

BACKGROUND OF THE INVENTION 
Organic materials, whether natural or synthetic, are conventionally 
protected against degradation by oxidation and by ultraviolet light and/or 
heat by incorporating a stabilizer in the materials. The choice of a 
stabilizer depends upon what particular source of degradation is to be 
countered, the type of material in which the degradation occurs, and the 
proposed length of time for which protection is sought under expected 
conditions. 
This invention is particularly directed to the protection of organic 
materials against degradation by oxidation at temperatures below about 
200.degree. C. for relatively short periods of time, and at ambient 
temperatures for extended periods of time. The compounds of this invention 
belong to a well-recognized class of antioxidants termed hindered 
phenols`, which as the term implies, possess an OH group which may be 
either partially or totally hindered by adjacent substituents on the 
phenol molecule. Compounds which serve as antioxidants are disclosed in 
Atmospheric Oxidation and Antioxidants by Gerald Scott, Elsevier 
Publishing (1965); Antioxidants Syntheses and Applications by Johnson, J. 
C., Noyes Data Corporation (1975); and other publications. 
Much work has been done in this art, and much has been written to explain 
the complex chemical reactions which occur when a material loses its 
structural integrity, flexibility or resilience, or becomes discolored. 
Much has been written to account for the stabilizing effects of hindered 
phenols, and the probable mechanisms by which these occur. Despite all the 
work and teachings related to it, the simple fact is that the stabilizing 
action of hindered phenols is unpredictable. 
Recognizing that most of the major developments in this field have been the 
products of a well-directed empiricism, and further, that the synthetic 
polymer industry has absorbed much of the teachings from the rubber 
industry where hindered phenols have long been favored, it is nevertheless 
surprising that four (4) hindered phenol moieties may be linked to form a 
cyclic compound which has the best characteristics of the most effective 
hindered phenols even when used in different media. As those skilled in 
the art are well aware, stabilizers which are effective in natural or 
synthetic rubber are usually ineffective in other synthetic resinous 
materials. 
Some examples of phenolic antioxidants are 2,6-di-t-butylphenol; 
2-methyl-4,6-dinonyl phenol; 2,6-di-t-butyl-p-cresol; 
2,2'-methylene-bis-(4-methyl-6-t-butyl phenol); 
1,1'-methylene-bis-(2-naphthol); 4,4'-methylene-bis-(2,6-di-t-butyl 
phenol); 4,4'-thio-bis (6-t-butyl-m-cresol); and the like. Although any 
phenolic antioxidant used in combination with the substituted 
metacyclophanes would improve the heat and oxygen stability of the 
compositions the more preferred phenolic antioxidants are those having 
alkylhydroxyphenyl substituents on an ester or a heterocyclic nucleus. 
Particular examples of phenolic antioxidants having alkylhydroxyphenyl 
substituents on an ester nucleus are compounds disclosed in U.S. Pat. No. 
3,330,859 exemplified by di-lauryl 
.alpha.,.alpha.'-bis(3,5-di-butyl-4-hydroxybenzyl)malonate; and disclosed 
in U.S. Pat. No. 3,627,725 exemplified by tetrakis 
(methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate) methane; and 
the like. 
Examples of phenolic antioxidant compounds having alkylhydroxyphenyl 
substituents on a heterocyclic nucleus are compounds where the 
heterocyclic nucleus is a triazine nucleus such as compounds disclosed in 
British Pat. No. 977,589 and exemplified by 
2,4,6-tris(4-hydroxy-3,5-di-t-butyl benzylthio)-1,3,5-triazine; compounds 
disclosed in U.S. Pat. No. 3,706,740 and exemplified by 
2,4,6-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-1,3,5-triazine; disclosed in 
U.S. Pat. No. 3,567,724 and exemplified by 
hexahydro-1,3,5-tris[3,5-di-t-butyl-4-hydroxyphenyl) propionyl]s-triazine; 
disclosed in U.S. Pat. No. 3,694,440 and exemplified by 
1,3,5-tris(4'-hydroxy-3',5'-di-t-butylphenylpropionyloxyethylthiopropionyl 
)hexahexahydro-1,3,5-triazine; and the like. 
Examples of phenolic antioxidant compounds having alkylhydroxyphenyl 
substituents on an isocyanurate nucleus are compounds of the formula 
disclosed in U.S. Pat. No. 3,531,483 and exemplified by 
tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate; disclosed in U.S. Pat. 
No. 3,678,047 and exemplified by 
2,2'2"-tris(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)ethyl 
isocyanurate; and the like. 
Still other hindered phenols useful as thermal antioxidants are disclosed 
in U.S. Pat. Nos. 3,920,659; 4,069,195; and 4,326,061 which are 
incorporated herein by reference as if fully set forth. 
It is known that p-t-butylphenol and formaldehyde, when base-catalyzed, 
yield a series of cyclic compounds made up of tetramers, bishomooxa 
tetramers, octamers, and the like, which have been the subject of a 
detailed investigation, reported in a series of articles one of which is 
Calixarenes. II. The Isolation and Characterization of the Calix [4]arene 
and the BishomooxaCalix[4]arene from a p-t-Butylphenol-Formaldehyde 
Condensation Product, by Gutsche, David C. et al, Tetrahedron Letters, No. 
24, pp 2213-2216 (Pergamon Press Ltd., 1979). These compounds, when 
appropriately functionalized, have the ability to form complexes which are 
enzyme model candidates. As will immediately be evident, these calixarenes 
have their OH groups within the `main ring`, that is, the ring formed by 
the plural butylphenol molecules, and the condensation reaction occurs 
under base-catalyzed conditions, while the synthesis of this invention, as 
described hereafter, is non-catalyzed. It will also be evident that 
formaldehyde (normally available as an aqueous solution) and 
paraformaldehyde (normally a solid consisting essentially of polymers of 
formaldehyde) behave quite differently even if they are related compounds. 
SUMMARY OF THE INVENTION 
It has been discovered that a non-catalytic reaction of a 
2,2'-di-substituted alkane bisphenol such as 2,2'-di-t-butyl-bisphenol A 
with paraformaldehyde at elevated temperature in an aromatic solvent, 
yields a high melting cyclic compound forming a main ring consisting of 
two bisphenol molecules coupled through each of the available ortho 
positions by amethylene moiety. The main ring is positioned between 
flanking OH groups of a cyclic dihydrate which may be dehydrated under 
elevated temperature under reduced pressure. 
It has further been discovered that the cyclic compound, named 
[1.1.1.1.]metacyclophane (hereafter "metacyclophane", for brevity), is an 
excellent antioxidant both in rubber and in polypropylene, exhibiting 
especially good antioxidant activity at a temperature of about 150.degree. 
C. for a prolonged period of time. 
It is therefore a general object of this invention to provide a process for 
the preparation of metacyclophane comprising reacting a 2-2'-disubstituted 
bisphenol with paraformaldehyde at a temperature in the range from about 
120.degree. C. to about 200.degree. C. at a pressure in the range from 
about 1 to about 8 atmospheres, in the presence of a mutual solvent for 
said bisphenol and formaldehyde, and, recovering a solid reaction product. 
It is also a general object of this invention to provide a stabilized 
composition of matter comprising an organic material subject to 
degradative attack by oxygen, and an effective amount, sufficient to 
counter said attack, of a solid reaction product prepared by the foregoing 
process. 
It is a specific object of this invention to provide a novel compound 
identified as metacyclophane represented by the structure 
##STR1## 
wherein, R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 may each be the 
same or different and represent halogen, particularly chlorine or bromine; 
lower alkyl having from 1 to about 18 carbon atoms; alkoxy having from 1 
to about 18 carbon atoms; and, hydrogen; except that R.sup.1 cannot be 
hydrogen.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
The compound of this invention is conveniently prepared from commercially 
easily available raw materials, namely (i) bisphenol A, or an alkylene 
bisphenol wherein the alkylene group has from 1 to about 4 carbon atoms, 
such as methylene bisphenol; (ii) a monoolefin having from 2 to about 10 
carbon atoms, particularly isobutylene; and, (iii) paraformaldehyde. 
It is critical that, prior to reaction with paraformaldehyde, a bisphenol 
reactant be provided with a substituent on only one of the positions ortho 
to the OH group on each phenol moiety. This may be done by alkylation, 
alkoxylation, halogenation, or any other conventional reaction which will 
yield the desired ortho-compound, alkylation being most preferred. The 
substitutions at other positions are not critical, such substitution being 
mostly to affect the specificity of the subsequent reaction with 
paraformaldehyde to form the cyclic compound containing four phenolic 
("4-P") moieties with the OH groups positioned outside the 4-P ring. 
Alkylation, which is most preferred, of the bisphenol, produces a mixture 
of alkylated products which is then separated to yield the desired 
ortho-substituted bisphenol ("OBP") having one substituted and one 
unsubstituted ortho position, which configuration is essential for the 
formation of metacyclophane. 
In a specific instance, bisphenol A is butylated under acid catalytic 
conditions to yield a mixture of butylated materials I, II and III and 
cleavage products, as represented below, the largest component being 
4,4'-isopropylidene-bis(2-t-butylphenol), identified as (I). 
##STR2## 
An examination of the structure (I) shows that each ortho-substituted 
phenol moiety ("OPM") is swivelable about the methylene carbon atom 
bridging them. It will further be apparent that a reaction of (I) with 
paraformaldehyde will likely yield a wide array of condensation products, 
including oligomers and polymers of the reactants, one of which products, 
from a statistical point of view, might result in two bisphenol moieties 
being bridged with one or more methylene groups. 
Clearly, to bias the statistical possibility in favor of such an occurence, 
it will be most preferred to separate (I) from the other reaction 
products. This is preferably done by stirring the reaction mass in a 
hydrocarbon solvent, most preferably an alkane such as hexane, at room or 
elevated temperature, and crushing all the lumps of solid. Upon filtering 
the mixture, a white solid is obtained as the residue. This white solid is 
extracted with hot hexane which preferentially extracts (I), leaving a 
solid which is identified as (II). 
In an analogous manner, other substituted bisphenol compounds may be 
prepared which necessarily have two ortho positions substituted, one ortho 
position on each phenolic moiety being left unsubstituted. Compounds so 
formed may be represented by the structural formula 
##STR3## 
wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 may each be the 
same or different and represent halogen, particularly chlorine or bromine; 
lower alkyl having from 1 to about 18 carbon atoms, without regard for the 
spatial configuration such as normal, iso or tertiary; alkoxy having from 
1 to about 18 carbon atoms; and, hydrogen, except that R.sup.1 cannot be 
hydrogen. The alkyl substituents may be acyclic or cyclic, including 
alkyl-substituted cyclic, as long as the total carbon content conforms to 
the defined amount, and the same is true for alkoxy groups. The 
substituents may be the same or different, though it will be apparent that 
alkylation of the bisphenol as described hereinabove, to provide OBP 
having the structure (I) will have the same ortho substituent. 
The object is for form a metacyclophane. This term "metacyclophane" is used 
to name the 4-P ring compound without regard to the substituents on the 
phenyl rings, or those on the bridge between the phenyl rings of each OBP. 
The reaction to form a metacyclophane by reacting (IV) with 
paraformaldehyde is preferably carried out in an aromatic or aliphatic 
solvent which is inert relative to the reactants in the temperature range 
of from about 120.degree. C. to about 200.degree. C. in which range the 
reaction occurs best under pressure and without a catalyst. Such solvents 
are benzene, toluene and xylene, and alkanes having from 5 to about 10 
carbon atoms. Most preferred is xylene. 
In the specific instance where the OBP (I) is to be reacted with 
paraformaldehyde, the reaction is most preferably carried out in xylene as 
the solvent, at about 175.degree. C. under autogeneous pressure, and the 
reaction is found to produce metacyclophane dihydrate having the structure 
(V) herebelow, where the precise linking of the phenolic OH groups with 
the water molecules is not given. Elevated pressure in the range of from 
about 2 to about 8 atmospheres appears to give the best results, though 
still higher pressure may be justified if it was economical. 
A laboratory preparation of [1.1.1.1.]metacyclophane dihydrate having the 
structure (V) is as follows: 
##STR4## 
100 g (0.293 mol) of (I) and 10.6 g (0.353 mol) paraformaldehyde were 
charge to a 1780 ml stainless steel autoclave containing xylene and heated 
at 175.degree. C. for 12 hr. The reaction mass is then cooled, filtered, 
and the solvent removed under vacuum. A yellow friable glassy material 
results. This material is stirred in acetonitrile for about an hour, after 
which time a white powder remains. Upon filtration, a white solid is 
recovered which has a melting point (m. pt.) of 325.degree.-330.degree. C. 
Additional material is recovered by concentration of the acetonitrile to 
provide a yield of 20 g of (V). 
An analytical sample of (V) is obtained by column chromatographing 2g of 
(V) on 150 g of 0.063--0.2 mm silica gel (obtained from ICN 
Pharmaceuticals, Inc.) using as eluent 1:3 ratio of hexane : chloroform in 
a 4.times.30 cm column. 
Calculated analysis for C.sub.48 H.sub.64 0.sub.4.2H.sub.2 O is: C=77.84; 
H=9.19. Found: C=78.05; H=9.13. 
IR analysis (Nujol): Absorptions at 3460, 3570 and 3615 cm.sup.-1 (OH 
groups) and, 1180-1200 cm.sup.-1 (Ar-O) 
Field desorption mass spectrography (FD/MS) gives a mol wt of 704. 
A Karl Fischer determination for water gave 4% (theory is 4.8%). 
The molecules of H.sub.2 0 are represented in the structure as being 
associated with the OH groups at each end, though it is not certain 
whether the molecules of water may be associated in a different manner. 
Though two (2) molecules of H.sub.2 O are represented it will be evident 
that either one or both may be present if one or the other are removed 
selectively, or both. 
The water from the complex (V) may be removed as follows: 0.5 g of (V) was 
dissolved in deoxygenated chloroform (10 ml) and a small chunk of 
CaH.sub.2 was added. Rapid bubbling occurred for about an hour. Upon 
filtration and evaporation of the filtrate by a stream of nitrogen, a 
yellow glassy material was obtained. This glassy material was stirred in 
acetonitrile for about 15 mins, filtered and dried to give a light colored 
powder (0.25g) the structure of which was confirmed by analysis to be that 
of [1.1.1.1]metacyclophane monohydrate, which is further dehydrated by 
heating at 110.degree. C. at 2 mm Hg. The dehydrated structure (V) may 
also be more correctly named 
5,11,17,23-tetra(1,1-dimethylethyl)-2,2,14,14-tetramethylpentacyclo[19.3.1 
.1..sup.3,7 -1..sup.9,13 l.sup.15,19] 
octacosa-1(25),3,5,7(28),9,11,13(27),15,17,19(26),21,23-dodecane-6.10,18,2 
2-tetrol. 
Molecules of the foregoing structure could mimic, in vitro, the catalytic 
activity of enzymes due to the complexing ability of the dual OH groups at 
opposite sides of the cavity-like structure. 
The metacyclophanes are generally high melting crystalline solids soluble 
in acetone, diethyl ether, dioxane, tetrahydrofuran, carbon tetrachloride, 
chloroform, lower primary alcohols having from 1 to about 5 carbon atoms 
such as methanol, ethanol and propanol, aromatic hydrocarbons such as 
benzene and toluene, but much less soluble in aliphatic hydrocarbons such 
as hexane. Substituted metacyclophanes are generally insoluble in water; 
they range in color from white to dark brown when pure. 
The amount of the metacyclophane used as a stabilizer will vary with the 
particular organic material to be stabilized and also the particularly 
substituted metacyclophane employed. Generally however, for effective 
stabilization of organic materials against oxidation, an amount of the 
metacyclophane used in the range from about 0.001 percent to about 10 
percent by weight (% by wt) based on the weight of organic material. In 
typical stabilized compositions the amount of metacyclophane used is in 
the range from about 0.01 to about 5% by wt. 
Compositions of this invention are both natural and synthetic organic 
materials, particularly resinous materials which have been stabilized to 
combat the deleterious effects of oxidative degradation such as is usually 
evidenced by discoloration and/or embrittlement. Such compositions are 
also desirably stabilized against degradation due to heat and actinic 
light, and therefore generally include additional, secondary stabilizers 
to achieve greater stability (hence such secondary stabilizers are 
referred to as "synergists" ). Such synergists may be present in the range 
from about 0.1 part to about 10 parts by wt, and preferably from about 0.2 
part to about 5 parts by wt per 100 parts by wt of the organic continuous 
phase. 
Of several types of known UV synergists, particularly favored are those 
disclosed in U.S. Pat. Nos. 3,325,448; 3,769,259; 3,920,659; 3,962,255; 
3,966,711; and 3,971,757; inter alia. 
When used, antioxidant synergists, whether only one, or more than one is 
used as a secondary antioxidant, range from about 0.1 part to about 20 
parts by weight, preferably from about 0.2 part to about 5 parts by weight 
per 100 parts by weight of the material. Among secondary antioxidants used 
are phosphite, phosphate, sulfide and phenolic antioxidants, the first and 
last being preferred. Most preferred are phenolic antioxidants such as 
2,6-di-t-butyl paracresol; 2,2'-methylene-bis-(6-t-butyl-phenol); 
2,2'-thiobis-(4-methyl-6-t-butyl-phenol); 
2,2'-methylene-bis-(6t-butyl-4-ethyl-phenol); 
4,4'-butylene-bis-(6-t-butyl- m-cresol); 
2-(4-hydroxy-3,5-di-t-butylanilino)-4,6-bis-(octylthio)-1,3,5-triazine; 
hexahydro-1,3,5-tris-(3,5-di-t-butyl-4-hydroxyphenyl)-propionyl-s-triazine 
; hexahydro-1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate; 
tetrakismethylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate methane; 
and other antioxidant synergists such as distearyl thiodipropionate; 
dilauryl thiodipropionate; tri(nonylphenyl) phosphite; tin thioglycolate; 
and particularly commercially available antioxiants such as Goodrite.sup.R 
3114, and 3125, Irganox 1010, 1035, 1076 and 1093. Other ingredients such 
as pigments, tackifiers, flame retardants, fungicides, and the like may 
also be added. 
Organic materials which may be thus stabilized against thermal, uvlight 
and/or particularly oxidative degradation, include copolymers of butadiene 
with acrylic acid, alkyl acrylates or methacrylates, polyisoprene, 
polychloroprene, and the like; polyurethanes; vinyl polymers known as PVC 
resins such as polyvinyl chloride, copolymers of vinyl chloride with 
vinylidene chloride, copolymers of vinyl halide with butadiene, styrene, 
vinyl esters, and the like; polyamides such as those derived from the 
reaction of hexamethylene diamine with adipic or sebacic acid; epoxy 
resins such as those obtained from the condensation of epichlorohydrin 
with bisphenols, and the like; ABS resins, polystyrene, 
polyacrylonitrille, polymethacrylates, polycarbonates, varnish, 
phenol-formaldehyde resins, polyepoxides, polyesters, and polyolefin homo- 
and copolymers such as polyethylene, polypropylene, ethylenepropylene 
polymers, ethylene-propylenediene polymers, ethylene-vinyl acetate 
polymers, and the like. The substituted metacyclophanes can also be used 
to stabilize mixtures and blends of polymeric materials such as ABS resin 
blends, PVC and polymethacrylate blends, and blends of polyolefin 
homopolymers and copolymers such as blends of polypropylene in EPDM 
polymers. 
Many known compounding ingredients may be used along with the 
metacyclophanes in stabilized compositions. Such ingredients include metal 
oxides such as zinc, calcium and magnesium oxide, fatty acids such as 
stearic and lauric acid, and salts thereof such as cadmium, zinc and 
sodium stearate and lead oleate; fillers such as calcium and magnesium 
carbonate, calcium and barium sulfates, aluminum silicates, asbestos, and 
the like; plasticizers and extenders such as dialkyl and diaryl organic 
acids like diisobutyl, diisooctyl, diisodecyl, and dibenzyl oleates, 
stearates, sebacates, azelates, phthalates, and the like, ASTM type 2 
petroleum oils, paraffinic oils, castor oil, tall oil, glycerin, and the 
like. 
The metacyclophanes, and the other compounding ingredients if used, can be 
admixed with organic materials using known mixing techniques and equipment 
such as internal mixing kettles, a Banbury mixer, a Henschel mixer, a 
two-roll mill, an extruder mixer, or other standard equipment, to yield a 
composition which may be extruded, pressed, blowmolded or the like into 
film, fiber or shaped articles. Usual mixing times and temperatures can be 
employed which may be determined with a little trial and error for any 
particular composition. The objective is to obtain intimate and uniform 
mixing of the components. A favorable mixing procedure to use when adding 
a metacyclophane to an organic material is either to dissolve or suspend 
the compound in a liquid such as hexane or benzene before adding it, or to 
add the metacyclophane directly to the polymeric organic material, or to 
extruder-mix the metacyclophane and the polymeric material prior to 
forming the product. 
Samples of the compositions are evaluated for oxidative and thermal 
stability by ASTM Standard Methods for Rubber. The results, measuring the 
time to discoloration and/or embrittlement of samples after aging in an 
air circulating oven at 125.degree. C. and 150.degree. C. (comparing 
samples containing commercially successful antioxidants, and 
[1.1.1.1]metacyclophane), are presented in Table I herebelow. Degradation 
of the samples can be followed by periodically measuring tensile strength 
left, and other standard ASTM tests. Failure of the sample may also be 
checked by visual signs of cracking when a sample is bent 180.degree. . 
With specific regard to mineral filled natural rubber such as is used in 
the white sidewalls of automobile tires, metacyclophane and Agerite 
Superlite (a commercially successful antioxidant) were each tested, a 
comparsion set forth in Table I hereinbelow showing that the stabilized 
rubbers each retained a similar percentage of its original physical 
properties, and the composition containing metacyclophane has better color 
retention after 24 hr exposure to a standard RS sun lamp. 
TABLE I 
______________________________________ 
Compound ingredients 
mix #1 mix #2 mix #3 
______________________________________ 
Natural rubber (SMR-5) 
100 100 100 
Reogen 2 2 2 
Stearic Acid 2 2 2 
Zinc Oxide 5 5 5 
Dixie Clay 50 50 50 
Atomite 50 50 50 
TiO.sub.2 20 20 20 
Sulfur 2.75 2.75 2.75 
Altax 1 1 1 
Methyl Tuads (accelerator) 
0.1 0.1 0.1 
AR Superlite Solids (antioxidant) 
-- 1.5 -- 
[1.1.1.1]metacyclophane 
-- -- 1.5 
PHYSICAL PROPERTlES 
Press Cures at 153.degree. C. (307.degree. F.) 
Cured for 10 min. 
300% modulus,psi 680 700 720 
Tensile, psi 2540 2660 2460 
% Elongation 610 610 580 
Hardness 60 60 60 
______________________________________ 
The following data were obtained after aging samples in test tubes 
according to the procedure set forth in Determination of Heating in Air 
(test tube procedure) ASTM D-865. 
______________________________________ 
AFTER AGING TWO (2) 
DAYS IN TEST TUBES @ 100.degree. C. 
Tensile, % retained 
28 61 59 
Elongation, % retained 
57 77 72 
Hardness, pts. change 
-4 +4 +5 
AFTER AGING FOUR (4) 
DAYS IN TEST TUBES @ 100.degree. C. 
Tensile, % retained 
17 34 39 
Elongation, % retained 
28 53 55 
Hardness, pts. chage 
-4 +3 +5 
COLOR -BEFORE AND 
AFTER 24 HR UNDER U-V LAMP 
Unexposed white white white 
Exposed lt. yellow yellow lt. yellow 
MOONEY SCORCH @ 121.degree. C. 
Mins. to 5 point rise 
33 37 31 
Plasticity 12 14 13 
RHEOMETER @ 153.degree. C. 
30 min motor, 60 sec 
preheat, 100 range, 3.degree. Arc 
T90 min 5.4 5.6 5.1 
T2 min 3.1 3.3 2.8 
______________________________________ 
In synthetic rubber, metacyclophane was equivalent to butylated 
hydroxytoluene (BHT) after oven-aging at 70.degree. C. for 10 days but 
does not leach out as readily as BHT. 
In petroleum based stocks such as Gulf Oil's PAO, Emery Corp.'s 2960, and 
Hercules Chemical's Hercolube A, metacyclophane is not as effective an 
antioxidant as some commercially successful products. 
In the following Table II is set forth a comparison setting forth average 
days to failure of three (3) polypropylene (Profax 6501) specimens into 
each of which was mixed equal amounts (0.1 part by wt) of stabilizer per 
hundered parts resin, (`phr`). 
TABLE II 
______________________________________ 
Days to Failure* 
Stabilizer (0.1 phc) 
at 125.degree. C. 
at 150.degree. C. 
______________________________________ 
Goodrite 3114 44 1.3 
[1.1.1.1]metacyclophane 
44 3. 
crude reaction product** 
35 3. 
______________________________________ 
*average of three (3) 25 mil thick plaques 
**from reaction mass for making [1.1.1.1]metacyclophane 
In the following Table III is set forth a comparison of evaluations of 
samples of 20 mil thick plaques of polypropylene containing a commercially 
successful antioxidant (Vanox GT) and [1.1.1.1]metacyclophane, when each 
antioxidant is used in conjuction with a secondary antioxidant (synergist) 
which produces a synergistic effect. 
TABLE III 
______________________________________ 
Componenets Set #1 Set #2 
______________________________________ 
Polypropylene (Profax 6501) 
100 100 
Vanox GT 0.1 -- 
[1.1.1.1]metacyclophane 
-- 0.1 
DSTDP* (sec.antiox.) 0.3 0.3 
Color white white 
Oven aging at 150.degree. C. (hr to failure) 
1836 900 
______________________________________ 
*Distearylthiodipropionate