Note: Descriptions are shown in the official language in which they were submitted.
7l~7Z-I
I~PROVED PROCESS FOR PRODUCING ET~IYLENE GLYCOL
This invention relates to a process for producing ethylene gly-
col from methanol.
eACKGROUND OF I~IE INVENTION
.
Dwindling petroleum reserves and increasing prices have placed
an increased emphasis on the use of synthesis gas in place o~ oil as a
starting material for producing various chemicals, such as methanol,
formaldehyde and ethylene glycol. The advantage of synthesis gas is that
it can be produced from raw materials other than petroleum, such as natural
gas or coal, and potentially from oil shale and tar sands.
An example of an industrial process for the production of ethy-
lene glycvl utilizing synthesis gas as a starting material is the reaction
of formaldehyde with carbon monoxide and water at high pressures ~over 300
atmosp}ieres) in the presence of an acid catalyst to produce hydroxyacetic
(glycolic) acid, which is then reacted with methanol to give the methyl
ester; the latter is then converted to the glycol by catalytic hydrogenat-
ion. See U.S. Patents Nos. 2,316,564, issued April 13, 1943 to Coc~erill;
2,153,064, issued April 4, 1939 to Larson; and 2,152,852; 2,385,448 and
2,331,094, issued April 4, 1939,June 9, 1942 and October 5, 1943, respect-
ively, to Loder.
Another proposed process utilizing synthesis gas for the product-
ion of ethylene glycol is the reaction of methanol and carbon monoxide us-
ing a rhodium-catalyzed, high pressure process; see U.S. Patents Nos. 4,115,
428, issued to Vidal et al, and 4,115,433, issued to Cosby et al on Sept-
ember 19, 1978.
With respect to the type of process for the production of ethyl-
ene
c-5957/5957A
glycol disclosed and claimed herein, it should be noted that the oxidative
dimerization or dehydrodimerization of a large variety of organic compounds
by peroxides is very old art thatwas pioneered by the preeminent free radical
theoretician M. S. Kharasch and his students. These studies became the foun-
dations of much subsequent free radical chemlstry. Kharasch et al in JACS
65, 15, 1943 show the dehydrodimerization of acetic acid to succinic acid
with acetyl peroxide in a 50 mole percent utilization selectivity based on
acetyl peroxide, utilization selectivity being defined as the moles of dehydro-
dimer product made divided by the moles of peroxide converted. Isobutyric
acid produced tetramethyl succinic acid in a 42.4 mole percent utilization
selectivity. Kharasch et al in J. Org. Chem 10, 386, 1945 show the ester
methyl chloroacetate being dimerized to dimethyl dichloro succinate by acetyl
peroxide in a 41 percent utilization selectivi~y.~ Kharasch et al in J. Org.
Chem. 10, 401, 1945 show the dimerization of cumene and ethyl benezene with
acetyl peroxide in 61.9 mole percent and 32.1 mole percent respectively to
their dehydrodimers. Wiles et al in I, E & C, August 1949, page 1682, tell
of the efficacy of di-t-butyl peroxide and 2,2 bis (t-butyl peroxy) butane
for the dimerization of cumene to l,1,2,2-tetramethyl lt2-diphenyl methane.
The benzoate ester of benzyl alcohol was dimerized to the dibenzoate ester
of the corresponding glycol, diphenylene glycol, with di-t-butyl peroxide
by Rust et al, JACS 70, 3258 tl948).
The literatule is replete with many other examples showing production
of dehydrodimers at very low concentrations at utilization selectivities of
generally from 20-50 mole percent, based on the peroxide consumed. Such selec-
tivities are generally too low for a process to be considered for commercial
development.
In connection with ethylene glycol, two teachings involving peroxide-
induced reactions should be mentioned:
The first is found in SchwetlicX et al, Angew. Chem. 72, 1960, No.
21, pages 779 and 780, and involves heating a mixture of di-tertiary butyl
7~
peroxide and methanol in a molar ratio of 1:20 in an autoclave and/or under
reflux for a period of 10 hours at 140C. A 26 percent yield of ethylene
glycol is reported, with the statement being made that an increase in the
alcohol excess raises the yiclds.
The second and more important of such other reaction paths to ethylene
glycol, in terms of its relevance to the present invention, is described by
Oyama in J. Org. Chem. 30, July, 19G5, pages 2429-2432. In particular, Oyama
shows the reaction of 9 moles of methanol, 1.8 moles of 15 percent aqueous
formaldehyde and 0.45 moles of t-butyl peroxide (di-tertiary butyl peroxide)
at 140C for 12 hours to give 0.21 moles of ethylene glycol (Table I at the
top of the right hand column on page 2430), with the statement being made
immediately below Table I: "The yield of ethylene glycol in the reaction
of formaldehyde with methanol is higher than that of t-butyl peroxide induced
dimerization of methanol. This fact suggests that hydroxymethyl radical (D)
adds to formaldehyde." Oyama describes in greater detail how this reaction
was run and the products obtained, and contrasts it with thc dehydrodimerization
of methanol in the presence of t-butyl peroxide and the absence of formaldehyde,
in the "Experimental" section beginning at page 2431 (particularly the sections
headed "Reaction of Methanol with Formaldehyde" and "Dimerization of Methanol"
on page 2432~.
The yields of ethylene glycol obtained by Oyama ara fairly low.
Oyama's only run with methanol - that involving the above-described reaction
of methanol, aqueous formaldehyde and t-butyl peroxide at 140~C for 12 hours -
gave only 1.86 weight percent of ethylene glycol.
The above-described reaction can be made to produce higher yields
of ethylene glycol by substantially decreasing the amount of organic peroxide
employed, relative to the amounts of formaldehyde and methanol present, from
that employed by Oyama. Moreover, increasing the amount of methanol and
decreasing the amount of water, relative to the other components of the reaction
mixture, in contrast to the amounts employed by Oyama, also appear to contribute
to the production o:E higher yields of ethylene glycol. Thus, for example,
heating a mixture of 78.5 weight percent of methanol, 1.5 weight percent of
di-tertiary butyl peroxide, 6.9 weight percent o:E Eormaldehyde and 13.1
weight percent of water at 155C for 2 hours gave a yield of ~.5 weight
percent of ethylene glycol in the product mixture. Thi.s is equivalent to a
yield of about 7.1 moles of ethylene glycol per mole of di-tertiary butyl
peroxide employed. (Oyama obtained 0.466 mole of ethylene glycol per mole
of di-tertiary butyl peroxide in his reaction). This improvement is more
fully disclosed in ~.S. Patent No. ~,337,371.
THE INVENTION
In accordance with the process of this invention, the production
of a lower amount of methylal by-product in ethylene glycol produced from
methanol and an organic peroxide, alone or in the presence of :Eormaldehyde
and water, is achieved by the addition to the reactants of a basic material
in an amount sufficient to reduce the hydrogen ions that are being formed
in the reaction without unduly reducing ethylene glycol production due to
by-product formation.
It has been found that in the production of ethylene glycol from
methanol and an organic peroxide, particularly in the presence of formalde-
hyde and water, acids such as formic acid are formed in the reaction which
catalyze the formation of methylal from methanol and formaldehyde. Keeping
the formation of methylal to a minimum is highly desirable in order to avoid
unduly large and expensive distillation requirements necessary for the pur-
ification of the ethylene glycol product. It has been discovered that if a
basic material is added to the reactants in a minor amount to reduce the
hydrogen ions that are being formed from the acid production, the amounts
of methylal by product are significantly reduced. The amo~mts of basic
ma,terI~al added to the reactants can be up to the amount required to neut-
ralize or partially neutralize the acid produced to prevent it from
catalyzing the react on of methanol and formaldehyde to form methylal. If
too much basic material is added -to the reactants, the formaldehyde formed
or added can be converted to formose sugars whicll will be readily apparent
by the amber color and characteristic odor of the reaction l:iq-lid and the
low formaldehyde accountability of the process. I~ith too much basic mater-
ial addit:ion, very small amounts of ethylene glycol will be produced.
The term "basic material" as used in this specification and
claims is meant -to include those materials which will control the amount
of hydrogen ions being produced in the form of acids in the reaction.
Suitable basic materials include the hydroxides Or alkali metals such as
lithium, sodium, potassium, rubidium or cesium or alkaline earth metals
such as calcium, strontium, barium, beryllium or magnesium. Also included in
the term "basic material" are salts of alkali metals or alkallne earth
metals and weakly ionizable acids such as oxalic, tartaric, malic, citric,
formic, lactic, acetic, carbonic, phosphoric, pyrophosphoric, pyrophosphorous,
propanoic, butyric, and others known in the art. Of specific interest for
purposes of this invention are the sodium and po-tassium salts of weakly
ionized acids such as acetic, formic, oxalic, carbonic ~including bicarbo-
nates) or phosphoric. Examples of these sodium and potassium salts include
sodium acetate, potassium acetate, sodium bicarbonate, potassi~ml bircarbo-
nate, sodium formate, potassium formate, sodium oxalate, potassium oxalate,
sodium carbonate, potassium carbonate, sodium pyrophosphate, potassium
pyrophosphate, sodium phosphate, potassium phosphate, sodium diphosphate,
potassium diphosphate and the like. The amount of a sodium or potassium
salt of a weakly ionized acid added to the reactants can range from about
50 to about 3500 par-ts per million, preferably about 100 to about 3000
parts per million, and more preferably about 100 to about 1500 parts per
million of the initial reaction mixture. In the case of other basic materi-
als, the amount should be equivalent to the amount stated for sodium and
3n potassium salts of weakly ionized acids with regard to their ability to
neutralize hydrogen ions in the system at hand. If a metal hydroxide such
as sodium hydroxide
. . ~
or po-tassium hydroxide is utilized as the basic material, the amount added
is no greater than would be required to neutrali~e the acids being formed
in the reaction. For example, the use of sodium hydroxide in an amount of
from about 25 to about 60 parts per million of the -total reaction product
resulted in production of satisfactory amounts of ethylene glycol and reduced
amounts of methylal compared to the reaction containing no basic materials.
In addition to those described previously, basic materials which can be used
include zinc oxide, basic alumina, various basic thorium compounds and in
general any basic material which will reduce the hydrogen ions of the acids
produced without interfering with the reaction.
For purposes of this invention, amounts of at least 0.25 weight
percent and as high as 25 weight percent of an organic peroxide, based on
the weight of the reaction mixture, can be use~ ~n producing ethylene glycol
from methanol, formaldehyde, orgar.ic peroxide and water, although, in general,
reaction feeds employed in practicing the present invention will contain no
higher than about 6 weight percent, e.g. from about 0.25 to about 6 weight
percent, and preferably no higher than about 3 weight percent, e.g. about
0.75 to 3 weight percent, of organic peroxide. In most cases, the feed will
also contain from about 45 to about 97 weight percent, preferably from about
80 to about 85 weight percent, of methar.ol, from about 0.5 to about 13 weight
percent, preferably from about 2 to about 12 weight percent, of formaldehyde,
and from about 0.5 to about 35 weight percent, preferably from about 2 to
about 10 weight percent, of ~ater.
This reaction will generally be carried out at a temperature of
from about 100C -to abou-t 200C, preferably from about 125C to about 175C,
at a residence time of no higher than about 8 hours, usually from about 0.25
hour to about 8 hours, and preferably from about 0.5 to about ~ hours. Generally,
the higher the temperature, the lower the reac~ion time necessary to bring
the reaction to a desired state of completion. There is little or no criticality
in the pressure at which the reaction is carried out. Pressures of between
autogenous pressure to about 600 psig can be utilized.
For the reaction of methanol with an organic peroxide in the absen-
ce of water and formaldehyde, the amount of methanol ;n the reac-tion feed
will be from about 70 to about 95 welght percent, preferably from about
75 to about 90 weight percent. Correspondingly, the amount of organic per-
oxide in the reactant feed will be from about 5 to about 35 weight percent,
and preferably from about 10 to about 25 weight percent. This reaction can
be conducted at temperatures ranging from about 100C to about 200C,
preferably from about 155C to about ]~0C. The time of reaction should not
exceed about ~ hours, and preferably will be from about 0.5 to about ~ hours.
Yields of ethylene glycol can range from about 2 to about ~ weight percent
of the total reaction products.
The organic peroxide employed in the process of this invention
has the formula
R-O-O-R
wherein R and Rl are each an alkyl or aralkyl group having 3 to 12 carbon
atoms. Organic peroxides which may be employed are, for example, di-
tertiary butyl peroxide, di-cumyl peroxide, tertiary-butyl cumyl peroxide
and tertiary-butyl ethylbenzyl peroxide. The preferred organic peroxide is
2n di-tertiary butyl peroxide.
The reactions may be carriecl out batchwise, wherein a reactor
such as a stirred autoclave is charged with the initial reaction mixture
which is then subjected to reaction, after which the entire reaction mixture
is withdrawn and purified, semi-continuously, in which the initial re-
action mixture is charged and product mixture withdrawn intermittently
from the reactor, or continuously, wherein the reaction mixture is charged
continuously and product mixture withdrawn continuously from the reactor. The
product mixture may then be purified using conventional techniques, such as
distillation or solvent extraction, to obtain ethylene glycol in the desired
3n purity, preferably fiber grade, and by-products such as tertiary butanol,
~`~` 7
methyl formate, glycerlne, acetone, and any methylal which is formed
during the process desplte the addition of basic material in accordance
with the invention.
The following examples will illustrate the invention:
Examples 1-21
Charges o:E the various feed compositions comprising methanol
~MeOHO),di-tertiary butyl-peroxide (DtBP), :Eormaldehyde (CH20) as a mix-
-ture of 36 weight percent CH20 containing about 14 weight percent ~leOH and
50 percent water(H20), sodium bicarboonate (NaHC03), except for Examples 13
and 14, in which no basic material was added, and any additional water in
the charge not present in the charged formaldehyde solution, were prepared
and charged to a 304 S.S. Hoke reactor at atmospheric pressure. The re-
actor was capped and placed in a thermostated oil bath held at the stated
reaction temperature and allowed to react for the stated reaction temper-
ature and the stated reaction time at autogenous pressure. After the re-
action time was completed, the reactor was cooled by quenching, vented, dis-
charged and analy~ed by gas chromatography for contained ethylene glycol
(EG) and methylal.
The results of these examples are shown in Table I which sets out
the composition of the initial charge, the temperature and reaction time
employed for the reaction and the amount of ethylene glycol produced in each
example, both in terms of weight percent of the product mixture and in
terms of moles of each product per mole of di-tertiary butyl peroxide con-
sumed in the reaction.
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As can be seen from the data in Table I, smaller amounts of methylal
are produced in the process when sodium bicarbonate is added to the reactants
compared to Examples 13 and 14 wherein no sodium bicarbonate was added.
In the control Examples 13 and 14, a trace of sodium bicarbonate
may be present in the reaction due to the fact that -the monomeric a~ueous
formaldehyde for the reactions was produced from paraformaldehyde. Thus,
a small amount of hydrogen chloride was added to depolymerize the paraformal-
dehyde to aqueous monomeric formaldehyde. After the aqueous monomer was formed,
a small amount of sodium bicarbonate was used to neutralize the solution using
the color chanye of litmus paper to indicate neutralization. This might have
resulted in the presence of a trace of sodium bicarbonate in Examples 13 and
14 wherein no additional sodium bicarbonate was added thus reducing slightly the
amount of methylal produced in these examples., Although the traces of sodium
bicarbonate which may have been present in Examples 13 and 14 would have been
much lower than the 0.013 weight percent added in Examples 7 and 8, the fact
that they could have resulted in some reduction in methylal production may
have contributed to a narrowing of the differences between the methylal produced
in Examples 13 and 14 wherein no bicarbonate was added and that produced in
the remaining examples ~herein bicarbonate in varying amounts was added, such
as Example 8. Irrespective of this factor, however, the result of Example
8 as well as the other examples wherein bicarbonate was added illustrates
that lower amounts of methylal are produced when higher amounts of sodiu~.
bicarbonate are utilized compared to control Exc~nples 13 and 14.
EXAMPLES 22-37
An initial reaction mixture containing methanol (MeOH), di-tertiary
butyl peroxide (DtBP), formaldehyde (CH2O) and water (H2O) and as the basic
material, sodium bicarbonate (NaHCO3)/ sodium acetate (NaO~c) or sodium formate
(NaFo) (except Example 22, in which no basic material was used), was charged
to a stainless steel bomb which was sealed and heated ~mder autogenous pressure.
--10--
The formaldehyde used was contained in a mixture of about 55 weight percent
of formaldehyde, about ~5 weight percent of methanol, about 10 wei~ht percent
water and 25 parts per million sodiurn hydroxide. To obtain the 5 weight percent
water content of the reactants, the formaldehyde mixture was diluted with
methanol or water whichever was needed to achieve the desired proportions.
After the prescribed reaction time, thc product mixture was removed from the
bomb and analyzed Eor ethylene glycol (EG) and other products such as methylal
tMeAl 1 .
The results of these examples are shown in Table II which sets out
the composition of the initial charge, the temperature, reaction time employed
for the reaction, the amount of ethylene glycol produced in each example,
both in terms of weight percent of the product mixture and in terms of product
EG per mole of di-tertiary butyl peroxide consumèd in the reaction. Methylal
by-product produced is sho~n in weight perccnt of the product mixture. It
should be noted that in Examplc ~2, the only example in this table not including
a basic material, a significantly larger amount of the by-product methylal
was produced than in the other expcriments.
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EXAMPLES 38-55
An initial reaction mixture containing methanol (MeOH~, di-
tertiary ~utyl peroxide (Dt~P~, formaldehyde ~C~l20), water, and in some
cases (Examples 41-55) sodium bicarbonate (NaHC03) was charged to a staln-
]ess steel bomb which was sealed and heated under autogenous pressure. The
formaldehyde used in these examples contained a mixture of about 55 weight
percent of formaldehyde, about 35 weight percent of methanol and about 10
weight percent water. As distinct from the formaldehyde used in Examples
22-37, no sodium hydroxide was present in this formaldehyde mixture. To
obtain the 5 weight percent water content of the reactants, the formalde-
hyde mixture was diluted with methanol or water whichever was needed to
achieve the proper proportions. After the prescribed reaction time, the
product mixture was removed from the bomb and analyzed for ethylene glycol
(EG) and methylal (MeAl).
The results of these examples are in Table [II which sets out the
composition of the initial charge, the temperature, reaction time
employed for the reaction, and the amount of ethylene glycol produced
in each example, both in terms of weight percent of the product mixture
(under products wt %~ and in terms of moles of ethylene glycol per mole
of di-tertiary bwtyl peroxide consumed in the reaction. Methylal by-product
produced is shown in weight percent of the produc-t mixture. It should be
noted that as the sodium bicarbonate is increased from 50 to 1500 parts
per million in the reactants, less by-product methylal is produced.
13
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EXA~IPLES 56~70
__
An initial reaction mixture containing methanol (MeOH)~ di-
tertiary butyl peroxide (DtBP), formaldehyde (Cll20), water and with or with-
out any of various buEfers was cllarged to a stainless steel (316-SS) auto-
clave (300 cc). All the examples were carried out at 155C Eor 2 hours under
autogenous pressures. All charges were stirred during the reaction excep-t
Examples 58 and 59. After -the prescribed reaction time, the product mixture
was removed from the bomb and analyzed for ethylene glycol (EG), formalde-
hyde (CE120) and methylal (MeAl). The various basic materials used are
identified as follows: NaOH (sodium hydroxide), NaFo (sodium formate), HFo
(formic acid)~ H3P04 (phosphoric acid), Na4P20710H20 (pyrophosphate) and
NaHC03 (sodium bicarbonate). The combination of phosphoric acid and sodium
hydroxide of Example 66 produces sodium phosphate. The combination of oxalic
acid and sodium hydroxide in Example 69 produces sodium oxalate.
The results of these examples are in Table IV which sets out
the composition of the initial charge, temperature, reaction time employed
for the reaction, basic materials and amount of ethylene glycol produced
in each example, both in terms of weight percent of the product mixture and
moles of ethylene glycol per mole of di-tertiary butyl peroxide consumed
in the reaction. The other products shown in the reaction product mixture
are formaldehyde and methylal. Table IV illustrates that with the use of
various basic materials, the amount of ethylene glycols produced can be
maintained at a satisfactory level with a small amount of methylal by-
product being producecl. Where no basic material was used larger amounts
of methylal were produced. In regard to Examples 64 and 65 where 5000 parts
per million of sodium formate were added, low yields of ethylene glycol were
o~ta~ned w~ith the production of small amounts of methylal. Sodium formate
(Examples 61-63) used as the basic material at a level of 1000 parts per
million resulted in a satisfactory amolmt of ethylene glycol and a small
amount of methylal. Example 70 in which sodium bicarbonate in an amount of
150 parts per million was utilized yielded
3~
a satisfactory amount of ethylene glycol but the amount of methylal produced
was slightly higher than other runs employing the same amount of sodium bicar-
bonate shown in Table III. This discrepancy is not understood and the result
of the experiment is believed to be anamolous. Sodium pyrophosphate (Examples
67-68) and sodium oxalate (Example 69) used as the basic material also yielded
satisfactory amounts of ethylene glycol and small amounts of methylal. The
addition of 60 parts per million of sod:ium hydroxide (Examples 58-60) yielded
satisfactory amounts of ethylene glycol and reduced amounts of methylal compared
to those results which contained no sodium hydroxide or any other basic material.
The results of the above examples indicate that satisfactory amounts of ethylene
glycol can be produced from methanol and formaldehyde and the coproduction
of methylal can be kept low when a basic material is used in accordance with
this invention.
-16-
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EXA~1PLES 71-79
An initial reaction mixture containing methanol (~eOH), di-tertiary
butyl peroxide (DtBP), fo~ialdehyde (CH2O), water and with or without any
of various ba~ic materials was charged to a stainless steel (316-SS) autoclave
(300 cc). The reaction was carried ou~ at a temperature ranging from 154-156C
for a reaction time ranging from 0.75 hour to 2 hours under autogenous pressure.
A11 runs were stirred. After the prescribed reaction time, the product mixture
was removed from the autoclave and analy~ed for ethylene glycol (EG) and methylal
(MeAl). The materials used as basic materials are identified as NaO~I (sodium
hydroxide) and NaHCO3 (sodium bicarbonate).
In Examples 71-74 where no basic materials were present, large amounts
of methylal are produced. In Examples 75-76 where small amounts of sodium
hydroxide were used, the amounts of methylal produced were significantly lower
than in Examples 71-74 but higher than in Examples 77-79 in which sodium bicar-
bonate was used. Although Example 79 using 0.42 weight percent (4200 parts
per million) sodium bicarbonate reduced the methylal content, a very small
amount of ethylene glycol was produced. There are indications that in this
run much of the formaldehyde was converted to formose sugars in view of the
amber color, characteristic odor and very low formaldehyde accountability.
The results of these examples are in Table V which sets out the
composition of the initial charge, the temperature, reaction time employed
for the reaction, and the amount of ethylene glycol and methylal produced
in each example.
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_ MPLES 80-93
These examples illustrate the use of additional basic materials
to reduce methylal production in the ethylene glycol process. An initial
reaction mixture containing methanol (MeO~I), di-tertiary butyl peroxide
(DtBP), formaldehyde (C~12O), wa-ter (ll2O) and the basic material was
charged to a glass reactor which in th:is case was a capped serum vial. The
vial was placed in a pipe reactor filled with methanol and sealed. lt
was then placed in a thermos-tated oil bath held at 155C and allowed to
react for 2 hours at autogenous pressure. After the prescribed reaction
time, the product mixture was removed from the glass reactor and analyzed
for ethylene glycol (EG) and methylal (MeAl).
The results of these examples are shown in Table VI which sets
out the composition of the initial charge and the amounts of ethylene
glycol and methylal produced. The basic materials used in the examples
were zinc oxide (ZnO), bismuth oxide (Bi2O3), Cerium oxide (Ce2O),
stannic oxide (SnO2), thorium oxide (ThO2), aluminum oxide (A12O3) and
sodium bicar~onate (NaHCO3) for comparison purposes.
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The results of Examples 80 to 85 which utilized a -feed stream
consisting of 87.25 weight percent of methanol, 2.0 weight percent o:E di-
tertiary butyl peroxide, lO.Q weight percent oE formaldehyde and 0~75
weight percent of water illustrate the improvement in terms of lower
methylal production obtainecl whe]l using zinc oxide as the basic material.
Thus, substantially lower amounts of methylal were obtained in Examples 84
and 85 utilizing zinc oxide, as compared with Examples 80 to 82 which
employed no basic material. Examples 84 and 85 also produced lower amounts
of methylal than Example 83 which utilized 0.005 weight percent of sodium
bicarbonate.
Examples 88 through 93 demonstrate the use of metal oxides
as the basic material utilizing a feed stream consisting of 92.55 weight
percent of methanol, l.0 weight percen-t of di-tertiary butyl peroxide, 6.0
weight percent of formaldehyde and 0.45 weight percent of water. Thus,
zinc oxi`de (Example 88), bismuth oxide ~Example 89), thorium oxide
~Example 92) and aluminum oxide ~Example 93) at a two weight percent level,
all produced lower amounts of methylal compared to the control Examples 86
and 87 which utilized no basic material. The use of bismuth oxide ~Example
89) and cerium oxide ~Example 90) produced somewhat lower amounts of methylal
than control Examples 86 and 87 but not as low as were obtained with the
other metal oxides as the basic material in this series of examples.
E~A~IPLES 93-100
These examples illustrate the effective use of sodium bicarbonate
as the basic material in the incremental addition of the reactants.
An initial reaction mixture containing methanol ~MeOH)~ a di-
tertiary butyl peroxide ~DtBP), formaldehyde ~CH2O), water and sodium
bicarbonate ~NallCO3) was charged to a 304 stainless steel lloke reactor at
atmospheric pressure. The reactor was capped and placed in a thermostated
oil bath held at 155C and allowed to react for l hour at autogenous pressure.
i\fter the first hour of reaction~ additional reactants, indicated as the
` 22
second stage, were added and the reaction continued for an additional hour.
Additional reactants were added in the same manner as the second stage
addition to provide additional stages as indicated in Table VII wherein the
total amounts of reactants are indicated in the various stages of addition.
After the last addition of reactants and -the completion of the reac-tion
(assumed to be one hour after the addition of the last por-tion of reactan-ts),
the reactor was cooled by quenching, vented, discharged and the contents
analyzed by gas chromatography for ethylene glycol (EG) and other products.
The results of these examples are shown in Table VII which sets
out the composition of the reactants charged to the reactor containing
methanol in the various stages. The amounts of the reactants used are re-
ported as weight percent of the total reactants. The amounts of ethylene
glycol and methylal where described are reported as weight percent of the
total reaction products.
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