Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2 ~ ~
POLYMERIZABLF MONOMFR MIXTURE
This invention relates to a polymerizable mixture of
isomeric methylethenyl benzenes and to polymers of such mixtures.
Styrene has been used for a long period of time in the
manufacture of polymers and polystyrene has attained a large market
for many purposes. Alkylated styrenes such as alpha-methylstyrene
have also been of interest for certain purposes.
The nuclear alkyl substituted styrenes have also been
used in various applications. The monomer which has been prin-
cipally used is known as vinyltoluene. This is a mixture whichconsists mainly of meta- and para-methyl styrenes (vinyl toluenes)
produced by the catalytic dehydrogenation of a mixture of the
corresponding m- and p-ethyltoluenes. The ethyltoluene mixture
is itself obtained by the fractional distillation of a mixture of
the o-, m~ and p-ethyltoluenes. The ratio of the m- and p-
isomers in the monomer mixture is approximately 65:35 (m:p). A
convenient summary of the preparation and properties of the monomer
mixture and of polymers produced ~rom it is given in "~tyrene: Its
Polymers, Copolymers and Derivatives" Ed. R.~. Boundy, R.F. Boyer,
ACS Monograph Series, 1952, Hafner Publishing Company, pages 1232
to 1245.
Vinyltoluene is produced by the dehydrogenation of ethyl-
toluene. Since the ethyltoluene starting material itself comprises
a mixture of isomers the vinyl toluene product will also comprise
an isomer mixture and the isomeric constitution will approximate
that of the original ethyltoluene. ~hus, if a different isomeric
distribution is desired in the vinyltoluene, the isomer distri-
bution of the ethyltoluene must be modified accordingly.
Processes for producing various mixtures of ethyltoluene isomers
30 are know. In these mixtures, the para isomer has generally been present in
~ 3L5~25~
an amount less than 40 weight percent with the meta isomer
generally present in a major proportion, together with smaller
amounts of the ortho isomer. U.S. Patent 2,763,702 (Amos et al),
for examplet describes a mixture of ethyltoluene isomers
resulting from ethylation of toluene with ethylene in the
presence of a Friedel-Crafts catalyst, such as aluminum chloride,
containing isomeric mn-ethyltoluenes in relative proportions
of from 8 to 30 percent of the ortho isomer, 40 to 65 percent
of the meta isomer and from 20 to 40 percent of the para isomer.
U.S. Patent 2,778,862 (Gorham et al) describes the ethylation of
toluene in the presence of an aluminum chloride catalyst to
yield an isomeric mixture in which the meta isomer predominates,
the para isomer is present to a lesser degree and the ortho
isomer is present in still smaller amount. A typical isomer
mixture disclosed contains 10 to 20 weight percent of ortho-
ethyltoluene, 25 to 30 weight percent oE para-ethyltoluene and
55 to ~0 weight percent of meta-ethylto:Luene. U.S. Patent
2,920,119 (Egbert et al~ refers to a conventional ethyltoluene
isomer mixture obtained by ethylation of toluene in the
presence of a Friedel-Crafts catalyst. This mixture has a meta
isomer content of 72 per~ent, a para isomer content of 20
percent and an ortho isomer content of 8 percent. U.S. Patent
3,720,725 (Olechowski) discloses a product mixture containing
about 45 percent of ortho-ethyltoluene, about 38 percent para-
ethyltoluene and about 3 percent of meta-ethyltoluene. This
mi~ture is obtained by alkylating an aromatic hydrocarbon in
the presence of a catalyst comprising a molybdenum halide, an
alkylaluminum dihalide and a proton donor.
The presence of substantial quantitites of the
ortho isomer in the ethyltoluene is highly undesirable because,
cn dehydrogenation, it tends to undergo ring closure with
formation of indenes and indanes which adversely effect the
- 2 -
~c,-,~
2 5 ~
properties of resultant polymer produced from the resultant
vinyl toluene. The indenes and indanes are difficult to
separate
- 2a -
115~25~
from the vinyl toluene. It has therefore been necessary to
remove the ortho isomer from the ethyltoluene ~y expensive
distillation techniques prior to dehydrogenation.
It is evident that the availability of ethyltoluene
in which the ortho isomer is either absent or present only in
trace amount would eliminate the necessity for expensive prior
removal of this isomer. Such products have not pre~iously
been available but in our U.S. Patent No. 4,143,084, issued
March 6~ 1979, and in the corresponding copending Canadian
Application No. 304,223, filed May 26, 1978, we have described
a process for preparing an ethyltoluene isomer mixture which
consists almost entirely of the para isomex. The ortho isomer
is either entirely absent or present in extremely small amounts.
Said U.S. Patent No. 4,143,084 and said Canadian application
disclose an ethyltoluene isomer mixture comprising at least
90 wt. % of p-ethyltoluene, 1-10 wt. ~ of _-ethyltoluene, and
0Ø1 wt. ~ of o-ethyltoluene.
According to the present invention we provide a
polymerizable mixture of isomers of met~yl ethenyl benzene
which consists essentially of 1-methyl-2-ethenyl benzene,
l-methyl-3-ethenyl benzene and 1-methyl-4-ethenyl benzene
in which the isomeric distribution is as follows:
Range - Wt. percent
Isomer Broad _eferred
l-methyl-2-ethenyl benzene 0-0.1 0 - 0.05
l-methyl-3-ethenyl benzene less than 15 less than 10
l-methyl-4-ethenyl benzene at least 85 at least 90
This polymerizable mixture is the direct product
of catalytic dehydrogenation of a mixture of ethyltoluene
isomers which comprises at least 90 wt. ~ of p-ethyltoluene,
1-10 wt. % of m-ethyltoluene, and 0-0.1 wt. % of o-ethyltoluene.
~ ~825~
In preferred mixtures the l-methyl-4-ethenyl
benzene comprises 97 to 99 weight percent (and preferably
98 to 99 weight percent), the 1-methyl-2-ethenyl benzene
0 to 0.1 weight percent (less than 0.05 weight percent)
with the l-methyl-3-ethenyl benzene making up the balance of
the ethenyl benzene content (preferably 1 to 3 weight percent).
~owever, the content of the l-methyl-4-ethenyl benzene may be
allowed to be as low as 95% without serious effects on the
resultant polymers.
- 3a -
. ~
~9
5 ~
The isoner mixture may contai~ ~mpurities and ad~entitious
materials in addition to the methyl ethenyl benzenes. Generally, these
other materials will not constitute re than 1 percent by ~relght o~ the
total mixture. Ihese other ~ater~?~s derive essen~ially from ~e process
used to make ~he meth~l ethenyl benzenes.
A typical isomer mLxture has the following analysis, by weight,
determdned by gas chromatography:
. ~_rcent
Tbtal ethengl benæenes 99.41
Residue:
Ethyl toluene 0.10
~sitylenes etc. 0.15
- Non-vinyllc
higher boilers ~
0.59 a.59 `
100 .00 ' `'~
E~h~n~l benzenes:-
l-ne~hyl-2-ethenyl benzene 0.05
l~et~yI--3-ethe~yl benzene 2.6
1-methyl-4-ethenyl benz~ne 97.4
Ihe mixture o~ the isoneric methyl ethenyl ben2enes may be
obtained by the catalytic dehydrogenatlon o~ a mix*uxe of the correspond~ng
ethyl toluenes. The deh~droOenation is suitably carried out under the
conditions conventionally used ~or the dehydrogen~tion of ethyl benzene to
~orm styrene. lhus, the dehydrcgenation will generally be carried out in
the vapor phase at ele~ated temperatures in the presence of' a dehydroOenation
catalyst. Ihe pressure may be at~ above or below atmospheric pressure.
Generzlly, for ease of operation~ atmospheric pressure is preferred but a
non-reactive diluent may be present to reduce the partial pressure o~ the
~ ~5~258
ethyltoluene so that the dehydrogenation is effectively carried out
under reduced pressure to obtain a favorable e~uilibrium. Water in
the form of steam is a suitable diluent and will generally be
present in a major proportion in the feed. Feed ratios from 1:1
to 5:1 are genrally preferred. Temperatures of 500 to 750C are
generally used, preferably from 600 to 650C. Liquid hourly space
velocities of about 1.2 (for ethyltoluene) are suitable and
preferred. Conversion is usually about 60~ with selectivities
of about 94% on the 1-methyl-4-ethenyl benzene isomer. Catalysts
are the conventional dehydrogenation type, generally comprising
complex oxide mixtures. ~ typical catalyst comprises ferric oxide,
potassium carbonate, cerium oxide and molybdenum oxide as follows:
1~1t. percent
Fe2O3 SS - 61
15 K2CO3 21 - 25
Ce2O3 4.6 - 5.6 (Ce)
MOO2 2.2 - 2.8
The eth~l toluene starting material may be obtained by
the process described in our co~pending Canadian Patent ~pplication
~o. 3~4,223, filed May 26, 1978. Upon dehydrogenation, the
isomeric distribution of the ehtyl toluene carries through to the
dehydrogenated product and therefore, a product high in the para
isomer (1 methyl-4-ethenyl benzene) is obtained. The ortho isomer
(l-methyl-2-ethenyl benzene) is either absent or present in only
trace amounts.
me method disclosed in co-pending Canadian application ~ 3~4,223
essentially invDlves the alkylation of toluene with ethylene in the presence
of oertain
~5--
115825~
. `
crystalline aluminosil~cate zeolite catalysts. The catalyst has a silica:
alumina ratio of at least 12 and a constraint index within the range of 1
to 1~. The process produces an extremely high proportion of the limethyl-
4-ethyl benzene isomer, with o~ly a mdnor proportion o~ the 1-methyl-3-
ethyl benzen`e i omer and negligible am~unts of the limethyl-2-ethyl benzene
iso~er. r~he almDst complete absence af the l-~.ethyl-2~et~yl ison~r is
highly ad~antageous because, as previously mentioned, this isomer tends to
produce undesired by-prcducts during the dehydrogenation step ~indanes and
i~d~nes which adversely ~f~ect the properties of the resultant poly~ers and
which cannot be easily separated ~rcm the met~yl ethe~yl benzenes).
rDhe mixtuxe of isom~ric methyl et~yl ben2enes m2y be sub~ected
to distillation prior to the dehydro~enation step in order to separa~e out
various by-products and after the dehydrogenation has been completed, a
flurther distilla~ion ~ay be ¢arrled out to separate the methyl ethenyl
be~zenes ~rom their sa~urated precur~ors.
Since the prcportion o~ the l-~ethyl-4~ethenyl benzene in the
mlx~ure is so hi~h, usually at le ~t 95 by weight, t~e mix~ure can be
regarded essentially as the para ~1,4-) lsomer.
Ihe mdxture o~ the mathyl ethenyl benzene isomers may be
polymerized by itself to produce polymers or with o~her copolymeriæable m~nomersto produce copolymers. In general, the polymer~zation conditions appropria~e
to styrene will also be use~ul with the methyl ethengl ben2ene mixture,
whether polymerlzed by i~self or with other monomers. qhus, polymerizatlon
may be e~fected under bulk conditions or in solutio~, suspension or emulsion
techniques comparable to those used ~or styrene polyme~lza~ion. 1he poly-
merization catalysts may be of the ~ree r~dical, anionic or cationic types.
Sultable free radical initiators include di-tertia~y butyl peroxidé, azobis
(isobutyronitrile), di-benzoyl peroxide, tertia~y butyl pe~benzoate, di cumyl
1 15~2~
peroxide and potassium persulfate. Cationic initiators are
generally of the Lewis acid type, for example, al~num trichloride,
boron trifluoride~ boron trifluoride etherate complexes, titanium
tetrachloride and the like. Anionic initiators are generally of
the organometallic type such as methyl lithium, ethyl lithium,
methyl sodium, propyl lithium, n-butyl lithium, sec-butyl lithium,
tert-butyl lithium, butyl sodium, lithium naphthalene, phenyl
lithium, phenyl sodium, benzyl lithium or cumyl sodium.
The polymers have useful and valuable properties which
distinguish them from related materials such as polystyrene.
The following Examples are given to illustrate the
in~ention. Example 1 describes a known procedure for producing
the ethyl toluene precursor. ~his process produces only a small
amount of the para isomer.
Example 1
To 100 ml. of toluene was added 1 gram of aluminum
chloride and ethylene at a rate of 40 cc/minute ~t a temperature
of 80C. After 2 hours, the composition was that shown in Table
1 below.
Table 1
Component
Benzene 0.20
Toluene 71.90
Ethylbenzene 0.17
Xylene
Para 0.15
Meta 0.06
ortho o
Ethyl Toluene
Para 6.43
Meta 14.37
Ortho 3.24
Higher 1.45
Other 1.99
The para/meta/ortho ethyltoluene ratio was 27/60/13.
~ -7-
1 15~258
ExamDle 2
A 5.3 ~r~m sample of the hydrogen form o~ ZSM-5 having a
crystalllte ~iæe o~ abou~ 2 micro~s was steamed a~ 515C. ~or a period of
2 hours and a feed ra~e of 8.8 cc of liquld wa~er per hour. Ihe temperature
was then raised to 640~C. Toluene was then ~ed at a rate of 180 ml per hour
~or a period of 4 hours and 15 minutes~ The tempera~ure w2s then reduced
to 550C., the catalyst flushed with nltrogen and then cooled to yield a
cohe-cont ~ product.
AIkylat~on o~ toluene
Toluene was aIkylated wlth ethylene in the pre~ence of the
above catalyst. qhe.condl~ions o~ reactlon included a temperature of 300C.
a welght hourly space veloclty of 7.4, a molar feed ratio o~ toluene to
ethylene of 5 and a st~eam time of one hour. qhe convers~on of toluRne obtai~ed
was 4.1 wel$ht percent and of ethylene 24.1 weight percent. Ihe ethyltoluene
.~soner ~ ture was found to conkain 93,15 weight percent o~ pa~a is~mer
and 6.85 weight percent o~ the meta isomer~
~g~ ~
~he ethyl to~uene isomer mlx~ure was passed o~er a complex oxide
zo dehydrogenation ca~alyst at a temperature o~ 620 - 640C and at atmospheric
p~es~ure. Water was present as a d~luent in aswater:ethyl toluene weight
ratio o~ 3:1~ qhe llquid hourly space velocity was 1.2. Convexsion ~s
about 60% per pass and the selectivity 94% ~or the para~isomer.
Ihe catalyst us~d ~as~irdler ~-64-CI~ ch had the ~ollowing
con~osition~
Wt. percent
23 55 - 61
K2C3 21 - 25
Ce20~ 4.6 - 5.5
MOO2 2.2 - 2.8
, ~r~ * Trademark
A~_ , _ _ _ _ __ . _ .__ _ .___, ._ __ .__ _. . _. _.. ~ _, .__ _ ,_ _~._ . __ ._ _ .. _ _ _ .. . . .. . .... _ . ~ .. _ .. _ . . .
1 ~15~258
Dhe isomeric distribu~ion of the dehydrogenated product was
the same as that ~or the ethyl toluene charge (93.15:6.85; para:meta;
ortho substanti~ly absent).
~
HZSM-5 having a cryst~llite size of 0.02 to 0.05 microns was
mi~ed with 35 weight percent alumlna blnder and extruded to produce a
1.5 mm. cylln~rical particle. A ten gram sample of this extrudate was
soaked overnight at room temperaturé in a solution of 8 grams of 85%
phosphoric acid in 10 ml of water. Ihe resulting product was filtered,
- dried at 120C. for about 2 hours and calcined at 500C. for approxlmately
an additional 2 hours. Ten gra~s of ~he phosphoxus impregnated extru~ate
was then soaked at rocm temperature overnight in a solution of 25 ~rams
o~ nagnesiun acetate tetrahydrate in 20 ml of water~ It was then filtered,
dried at 120C. ~or about 2 hours and then placed in a ~ur~ace at 500CC.
~or approximately 2 hcurs. ~he resulting product contained 4.18 weight
percent phosphorus and 7.41 weight percent m~gnesium.
~t~n ~ olo~
loluene was alkylated with ethylene ln the presence of the above
catalyst. qhe conditions of reaction ar.d analytical results are summarized
in qable 2 belo~.
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o a~
~1 o~
~O ~ 3
OCl~ L~ r1a~cr~ o o
~D O
O ~ L~ O ~~ ~D O
U~ O ~ ~, U~
U~
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o cr~
. . ~ . . . I
~ ~0 '
~ o ~ ~ c~ nO I 1 ~
:a
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h
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O ~I b~
~d S ~:: O V ~
O O ~, o ~ h --I
3 C.) _ o ~ ~ ~ S
1 ~5825~
Dehydrogenation of ethyltoluene
The ethyltoluene product was dehydrogenated using the
conditions specified in ExamPle 2 following an initial distilla-
tion step to remove any toluene starting material. The dehydro-
genated product was also distilled to remove unreacted ethyltoluene.
The isomer distribution of the dehydrogenated producttortho, meta, para) was equivalent to that of the ethyltoluene ~
starting material in each case.
Example 4
Preparation of polymer from mixture of methyl-ethenyl
benzene isomers.
The mixture of methyl ethenyl benzene isomers used had
the following composition (weight percent):
Methyl ethenyl benzenes 99.43
~thyltoluene 0.53
Xylenes, cumenes, mesitylenes 0.01
High boiling materials 0.03
Methyl ethenyl benzenes:
l-methyl-2-ethenyl benzene -(1)
1-methyl-3-ethenyl benzene 97.0
- 1 methyl-4-ethenyl benzene 3.0
Note: (1) Less than 0.05%
The mixture (120 g.) was dissolved in 46.75 g toluene
and 0.168 g. azobis (isobutyronitrile) and poured into a dry
~ 25 bottle which was then closed by a coupling/ball valve assembly~
;~ Dry nitrogen was then bubbled through the mixture in the bottle for
10 minutes by means of a needle inserted through the septum and the
open ball valve. The nitrogen exited through a short needle
piercing the septum on top of the ball valve. The two needles were
then removed, the ball valve closed and the bottle placed
,7,~",,r,~
- ~15~2~
in an oil bath at 60C for 96 hours and at Y0C for 24 hours.
The polymerized mixture was removed from the bottle by
dissolving it in additional toluene at 90C. ~he volume of the
final solution was about 400 ml. The polymer was then precipitated
by pouring the solution into about 1000 1500 ml methanol in a 4
liter blender "(Waring Blendor)"*, adjusting the stirring speed
to shred the polymer. The liquid was decanted and the polymer
washed once with methanol in the blender. The solid polymer was
filtered off and dried in a vacuum oven at 100C under vacuum for
48 hours.
The properties of the polymer were as follows:
Molecular wt (Mv-viscos. ~ve) 269 x 10 3
(Mn-number Ave) 158 x 10 3
TG, C 111
15 Vicat, C 119
Deflection temp. C Y8
Melt Index (Cond G~ 2.1
Density g/cc 1.008
Break strength, psi 6065
20 Elongation, % 3
Tensile Modulus:
Rheovibron, psi x 10 3 331
Instron, psi x 10 3 338
Impact strength, ft/lb-in 0.20
25 Haze 4.4
Transmittance, % 8Y.7
Pentane uptake 41.0
* Trademark
-12-
I .......... , .. . . .... ., . .. . . ., ... ,,.. ~. ~ .
: 115~25~
,
Exa~ples 4A, 4B~ 4C
Polymers prepared in th~ sa~e way as in Example 4 ~rom similar
m~no~er mix~ures containing different proportions of the p-isomer (l-methyl-
4-etheny1 be~zene) had the following properties:
Example lA lB lC
p isomer content, % 89.3 95.5 99.7
M~lec~llar wt (Mv x 10 3) 2n 278 269
(Mn x 10-3) - 168 177
TG, C 106 llO 113
~cat, C . 108 114 I18
Deflectlon temp. C 93 108 104
~ ~elt Index, (Cond G) 3.0 2.4 2 3
: Density g/cc 1.014 1.011 1.008
Break streng~h, psi 6010 5330 5170
Elong~tion, % 1.4 8 3
Tbn~lle Modulu$
Rheov1br2n, p~i x 10 3 363 325 355
Ins~ron, psi x 10 3 30g 301 332
pact Strenæth, ft/lb~in 0.28 0.13 0.21
Haze 5.0 4.2 5.2
Transmi~tance, % 88.3 88.7 88.7
: Pentane uptake 40.0 40.0 40.0
