Note: Descriptions are shown in the official language in which they were submitted.
~73~
PR-5612A
PROCESS FOR 1,1-DIHAL0-4-METHYL-1,3-PENTADIENES
.
Background of the Invention
This invention relates to the preparation of 1,1-
dihalo-4-methyl-1,3-pentadienes, which are key intermediates
in a known method for the production of certain pyrethroid
insecticides.
The term "pyrethroid" is commonly used to encompass
both naturally occurring and synthetic derivatives of cyclo-
propane carboxylic acid. Such compounds have been well known
for many years as broad spectrum insecticides. They have
generated particular interest in the insecticide art since
in spite of their high potency in controlling insects, they
have a low -toxicity toward mammals, and they degrade readily
after application, avoiding the accumulation of harmful
residues in the soil or plant tissues.
One of the most successful pyrethroids is 3'-
phenoxybenzyl 2~ dichlorovinyl)-3,3-dimethylcyclopro-
pane carboxylate, first reported by Elliott et al., Nature,
244, 456-457 (1973); ibid., 246, 169-170 (1973). This com-
pound and others similar in structure have an outstanding
combination of insecticide properites, notably an unusually
high potency. Since the discovery of this class of compounds-,
much effort has been expended in developing economical pro-
cesses for their manufacture.
The precursor ethyl 2-(~ dichlorovinyl)-3,3-
dimethylcyclopropane carboxylate was first prepared by amethod known prior to the Elliott et al~discovery. This
r~ethod is attributed to Farkas et al., Coll. Czech. Chem.
Comm., _, ~230 (1959), and involves the condensation of
- chloral with either isobutenyl magnesium bromide or iso-
butylene, using a free radical catalyst with the latter, to
produce a mixture of pentenols. The pentenols are then
reacted as follows:
~2
OH .
C ~ (CH3CO)20
OH ~ acetates
Cl~ ~
Zn, CH3CO2H CC
acetates ~_
.- ,~ p toluene
C ~ ~ sulfonic acid
. _ '
CC~
.
CC ~ . ~Cu~020 ~ Cl
/==\ C02C2H5
` ` ` Cl ~
/\
This compound is then converted to the Elliott et al.
pyrethroid by ester interchange.
`
The overall conversion of isobutylene to ~
dichloro-4-methyl-1,3-pentadiene~ the key intermediate in
5 the above reaction scheme, is reportedly less than 40%.
Furthermore, for every kilogram of 1,1-dichloro-4 methyl-
1,3-pentadiene produced, more than a kilogram of zinc dust
~s consumed It is clearly desirable to find more practical
and economical methods of producing the diene.
... .
.
_3_
A number of processes have been developed to
prt~duce the diene by direct synthesis. One such process,
which is based on the addition of trichloroethylene to iso-
butylene, is described in Hewertson et al., Ger. Offen.
2,629,868 (1977); Chemical Abstracts, 86, 15188s (1977).
This process involves two steps: first, a hot-tube reaction
between the starting materials with a free radical initiator
to form the l,4-diene, followed by an acid-catalyzed
rearrangement to the l,3-diene. Another process, described
in Holland et al., U.S. Patent No. 4,056,574 (1977),
involves the oxidative coupling of isobutylene with vinyli-
dene chloride in the presence of palladi~un acetate. The
product achieved' by this process is a mixture o~ the 1,3-
and 1,4-diene isomers together with non-chlorinated dienes.
Other processes involve the formation of either the''
unsaturated diene precursor, or a precursor containing a
single double bond, folLowed by dehydrohalogenation, dehydra-
tion, or both to form the diene. CLeare, U.S. Patent No.
4,018,838 (1977), describes a simplified version of the
Farkas et al. process described above, wherein the trichloro-
pentenol is reacted directly with powdered zinc in glacial
acetic acid to form the diene. Kay et al.~ Ger. Offen.
2,~57,148'(1977), Ch~m~c-l Abser=c~s, 87, 92654p (1977),
describes the electrochemical reduction of the trichloro-
pentenol in sulfuric acid dissolved in methanol. A similar
process is disclosed in Alvarez et al., U.S. Pa~ent No.
4~022~672 (1977~o Scharpf, U.S. Patent No. 4,081,088 (1978),
describes the formation of the l,l-dihalo-4~methyl-1-penten-
3-one by the condensation of a vinylidene
halide and an isobutyryl halide in the presence of a Lewis
acid9 followed by reduc~ion of the ketone to the alco~ol
with aluminurn isopropoxide and isopropanol, and dehydration
o~ thé alcohol to the dienè using an activated clay. A
similar process is reported by ~yseia et al., British Patent
No. 1,493,228 (1977), in which the reduction is performed
by an alkali metal borohydride. Lupichuk, U.S. Patent No.
4,070,4Q4 ~1978), describes the condensation of
~. ~
3-methyl-1-butene with a carbon tetrahalide, followed by
the base-induced dehydrohalogenation of the resulting 1,1,1,3- -
tetrahalo-4-methylpentane to form the diene. Alkali metal
hydroxides are designated as preferred bases for the dehydro-
~alogenation, and one equlvalent is used for each mole ofhydrohalide eliminated. The product is characterized by
low yields and substantial by-prodact formation.
Dehy~rohalogenation has also been disclosed in
Belgian Patent No. 842,180 (1976) to Shell International
Research, wherein an equivalent of tertiary amine is used
for each mole of hydrohalide eliminated. Dehydrohalogenation
combined with dehydration has been disclosed in Lantzsch et
al.~ British Patent No. 1,494,817 (1977).
Summary of the Invention
It has now been discovered that 1,1-dihalo-4-
methyl-1,3-pentadienes can be prepared to a high degree of
selectivity by the catalytic dehydroh~logenation of 1,1,1,3-
tetrahalo-4-me~hylpentane.
.
Specifically, the process of the present invention
comprises heating a 1,1,1,3-tetrahalo-4-methylpentane to a
temperature of from about 150C to about 200C in the presence
of a catalytic amount of a nitrogen base halide salt selected
rom the group consisting of
tertiary amine hydrohalides in which the
substituents on the ni~rogen atom are
alkyl or cycloalkyl containing a minimum
of 3 carbon atoms each,
N-alkyl alkyleneimine hydrohalides in which the
alkyl group contains from 1 to 6 carbon atoms
and the alkylene gxoup contains from 3 to 7
carbon al:oms,
. quinoline hydrohalides, and
tetraalkylammonium halides in which at least three
of the alkyl groups contain a minimum of 3
carbon a~oms each.
, . ... .
.~ , .
~473
--5
The term "alkyl" is used herein to in lude both
straight- and branched-chain saturated monovalent hydro-
carbon radicals. Examples are methyl, ethyl, n-propyl, n-
butyl, lsobutyl, n-hexyl, 2-ethylhexyl, s-heptyl, n-nonyl,
n-dodecyl, etc. The alkyl radicals attached to a given
n~trogen atom may be the same or different and are subject
only to the limitations of steric hindrance which are
apparent to one skilled in the art. The preferred trialkyl-
amine hydrohalides are those in which the three alkyl groups
are identical, and range from 3 to 18 carbon a~oms each.
The most preferred are those with three identical alkyl
groups ranging from 4 to 15 carbon atoms each. The pre-
ferred N-alkyl pyrrolidine hydrohalides are those in which
the alkyl group ranges from 1 to 3 carbon atoms. The pre-
ferred tetraalkylammonium halides are those in which thealkyl groups are all straight-chain alkyls and the toLal
number of carbon atoms in all four alkyl groups ranges from
10 to 40, more preferably from 12 to 36~ and most preferably
from 16 to 32.
The preferred cycloalkyl groups are those ranging
from 5 to 8 carbon atoms, most preferably from 6 to 8 carbon
atoms. The carbon atoms in the cycle are optionally sub-
stituted by alkyl groups. Examples include cyclopentyl,
cyclohexyl, 3-methyLcyclohexyl, cyc lohep tyl, e tc~ -
The term N-alkyl alkyleneimine is used herein to
denote a compound of the formula
'
(C ~ N-R
where n is an integer and R is an alkyl group. As stated
above, R ranges from 1 to 6 car~on atoms and n ranges from
3 ~o 7. Preferably, R is rom 1 to 3 carbon atoms and n
is from 4 to 6. Examples are N-ethyl azetidine, N-methyl
pyrrolidine, N-propyl piperidine, etc.
All carbon atom ranges are in~ended to be inclu-
sive of their upper and lower limits.
,.. ...
~7~9
The terms "halogen," "halo," and "halide" are
used herein to include ~luorine, chlorine, bromine, and
iodine. PreEerred halogens are chlorine and bromine, with
chlorine particularly preferred.
The term "catalytie amount" is used herein to
denote any amount of the catalyst which will cause the
liberation of anhydrous hydrohalic acid from the tetra-
halogenated starting material.
Detailed Description of the Invention
According to the process o~ the present invention,
the 1,1,1,3-tetrahalo-4-methylpentane and the nitrogen base
~al~ are combined in the liquid phase and heated, and hydro-
halic acid is evolved as a gas The product, 1,1-dihalo-4-
methyl-1,3-pentadiene, is then recovered from the reaction
mixtare.
The process can be operated over a wide temperature
range, limited only by the desirability or minimizing char-
ring and by-product formation which may occur at high tempera-
ture, and by a low reaction rate at low ~emperatures. In
practical opera'ion, a temperature ranging from about 150C
to`about 200C, and preerably from aDou~ 170C``to about
190C, is employed. A condenser or heat exchanger can be
positioned above the reaction vessel to facilitate tempera-
t~re control and to condense any volatilized hydrocarbon
fr~m the hydrohalide gas which is driven off, and ~o return
the condensate to the reaction mixture. With a condenser,
the reaction is generally run under a partial re1ux~ since
full reflux at atmospheric pressure generally requires a
temperature higher than desired.
Aithough^t~e systém pressùre is not critical and
~- 30 can vary over a broad range, a pressure which is approximately
atmospheric is the most practical ~or the dehydrohalo~enation
reaction. Higher pressures offer little advantage since they
.~, .
~ 7
-7-
of~en necessitate a higher reaction temperature which is
undesirable for the reasons stated above. A high pressure
may also aggravate corrosion problems since the gas phase
above the reaction mixture is largely hydrohalic acid. Sub-
atmospheric pressures may offer an advantage under certainconditions, however, since they may promote the evolution of
the hydrchalide gas and permit efficient operation at a
lower reaction temperature. A purge of inert gas such as
nitrogen can also be used to promo~e the removal of hydrogen
halide gas~
There is no critical amount of catalyst for this
reaction. Any amount which will promote the reaction rate,
i.e., cause the evolution o~ hydrohalide gas, will suffice.
The actual amount which should be used is largely a function
of economic considerations, since the reaction rate increases
with increasing catalyst concen~ration. Generally, the
amount of catalyst is such that the initial mole ratio o~
catalyst to alkane starting material is from about 0.05 to
about 5.0, preferably from about 0.2 to about 2Ø
The catalyst can be pre-formed external to the
reaction system prior to being placed in the reaction vessel,
or it can be prepared in the reaction vessel itself. For in
situ catalyst prepara~ion, a propexly selected amine is
reacted with either anhydrous hydrogen halide gas or an appro-
priate organic halide, depending on whether ~he desired
catalyst is an amine hydrohalide or a quaternary ammonium
salt~ It is occasionally convenient to heat the catalys~
thus fonmed, in order to plaee it in the molten form, prior
to addition of ~he alkane if the catalyst is a solid at
ambient temperature.
Any method of combining the catalyst with the alkane
wlll suffice; either one may be added to the vessel first.
When the rea tion is run as a batch wide process, it is gen-
erally most convenient to combine the two components a~ ambi-
ent ~emperature and then to heat the mixture up to thetemperature level desired. The reaction is gPnerally com-
plete within a few hours.
.,.,~,~
73~
-8-
Rather than a mixture o~ diene isomers, the pro-
ducta when the process is run to completion, c~ sists
essentially of the l,l-dihalo-4-methyl-1,3-pentadiene.
Once the reaction is complete, the product can be separated
from the catalyst by distillation. It is advantageous to
place the vessel under a partial vacuum during the dis-
tillation, so that the'distillation can occur at a tempera-
ture at or below the reaction temperature.
The process can also be operated on a continuous
basis, whereby the alkane is continually fed to the system
and both the 'diene and the hydr~halide gas are continuously
removed. In this type of operation, the alkane is added
to the cata'lyst while the latter is already at reaction tem-
' perature. Continuous processes require either a recycle
system or a fractionating column OL considerably greater
complexity than a simple condenser, since a substantial
residence time is needed to complete the removal of two
moles of hydrohalide. A higher concentration of catalyst
is also needed. Improvements i~ efficiency can be achieved,
'' 20 however, by using a multi-stage system, such as a cascading
reactor arrangement. The various stages permit the use of
a combination of dif~erent temperatures and catalyst concen-
trations, which can be adjusted ~o maximize yield and mini-
mize the quantity of trichlorina~ed olefin in the product.
Product controL can also be achieved by the use oE a semi-
continuous process whereby feed and product streams are
intermittently shut down while the reaction remains running.
- ID general, the diene product can be recovered from
the reaction mixture by any conventional techni~ue, although
simple dis~illation under vacuum is the most practical
~' method. The catalyst remaining in the still pot can then be
re-used indefinitely for the treatment o~ a new batch of
starting ~aterial; no catalyst regeneration is necessary
unless the starting material itself contains high-boiling
,
,
73~
~ g
impurities which accumulate in th~ reaction vessel. The
product itself can be fu~her purified by any conventional
means. Olefin intermediates present in the product can be
either removed or converted to the diene by an additional
dehydrohalogena~ion. In general, the amount of olefin formed
can be minimized by increasing the reaction temperature, or
lncreasing the amount of catalyst used or the reaction time,
or by careful selection of the catalyst. The hydrohalide
gas can be pressurized, scrubbed, or fed to some other pro~
cess for use as a halogenation or neutralization ~ ent.
It should be clear from the above description that
numerous variations on the basic process are possible, and
all are intended to be incLuded within the scope of the pre-
sent invention. The following examples are offered for
purposes of illustration only, and are intended neither to
define nor limit the invention in any manner.
EXAMPLE 1
A 0.3-lit~r reaction vessel equipped with stirrer,
thermometer? and condenser and mounted in a heating mantle
was charged wi~h 14.2 grams (g) ~0.167 mole) of N-methyl- -
2Q pyrrolidine and 112 g (0.5 mole) o 1,1,1,3-tetrachloro-4-
methylpentane, hereinafter referred to as "TCMP," at ro~m
temperature. Heat was then applied while anhydrous hydrogen
chloride was added below the liquid surface; A total of
6.5 g ~0.178 mole) of HCl was added. When the system tem-
perature reached 185C, gas bubbles began to evolve from the
reaction mixture. The system was then kept under reflux for
7 1/4 hours, while the temperature gradually dropped from
185~C down to 170C due to the changing composition of the
reaction mixture. The reaction was monitored by gas
chromatographic analyses of liquid samples taken at periodic
intervals from the vessel. Prior to injection, each sample
was dissolved in carbon disulfide~ then washed first with
dilute HCl, and then water. The chromatogram data, exclu-
.. . . . . . . .. . ..
sive of the CS2 content of each sample, was as follows:
~' .
~. j .
-- -10-
TABLE I. Product Analyses
Reaction Produc~ in Area Percents
Time (h) DC~IP Tri TCMP
1~0 41.5 1~.1 44.4
2.0 62~4 11.8 25.8
3.0 77.7 8.1 14.1
5.0 94.7 ~.4 2.8
6.0 96.~ 1.8 1.6 -
7.25 98.6 1.0 0.4
DCMP ~ Dichloro-4~methyl-1,3-pentadiene
Tri : Trichlorinated olefins~
TCMP : 1,1,1,3-Tetrachloro-4-methylpentane
In each caseS a single diene peak appeared. When the final
reaction mixture was distilled and analyzed by nuclear mag-
netie resonance (NMR) spec~roscopy, it was confirmed that
the only diene present was 1,1-dichloro-4-methyl-1,3-
pentadiene, hereinafter referred to as "DCMP.t' No otherisomers were detected. The trichlorinated olefin inter-
mediates appeared as several isomers in separate peaks on
the chroma~ogram. The area percents for these were com
~ined to provide the ~igures shown aboveO Area percents
are ~aken from direct measurements of the area undex eac~
peak on the chromatogram trace. They are essentially
equivalent to mole percents, particularly where the;figures
are very close to zero or 100. ~ -
After the last sample was ~aken the system was
partially evacuated, lowering the pressure ~o 16 milli-
meters Cmm) of mercury. The produc~ was distilled of
fr~m the reaction mixture at this pressure at a ~emperature
of 61-65C. ~The product was ~hen ~ried, weighed, and
analyzed. The yield o diene was 64.0 g, at 95.6 weigh~
percenk puri~y, corresponding to 81.0% yield.
~ ~.
~ ~L14~
-11
EXAMPLE 2
-
The procedure of Example 1 was followed using
67.2 g (0.3 mole) of TCMP and 16.6 g ~0.06 mole) of te~ra-
bu~ylammonium chloride. The lat~er was preformed, so that
nn in situ cataly~t generation was required. The reaction
was initiated at 166C and proceeded for 3.5 hours, while
the reflux temperature fell to 157C. Gas chromatographic
analy~is of the final product showed 72% DCMP, 10% tri-
chlorinated olefins, and 3% TCMP (area percents). No diene
isomer~ o~ DCMP were detected.
.
E:_
The procedure o~ Example 1 was followed using
196 g (0.5 mole) of Alamine 336R, 112 g (0.5 le) of TCMP,
and sufficient anhydrous HCl to saturate the reac~ion vessel.
Alamine 336 is a commercial pro~uct obtainable from Henkel
Corporation, Kankakee, Illinoi~9 and is identîfied as tri-
caprylylamine, wherein the tenm "caprylyl" represent~ a
mixture of s~raight-chain, sa~urated alkyl radical~ of 8 to
10 carbon atoms each, with the 8-~arbon chain predominating.
Alamine 336 has a molecular weight of 392.
The reaction was run for 2 ho~rs, reflu2in~ a~
180-188C. The f~nal product analysis revealed 98% (area~
DCMP, and no TCMP, trichlorinated 012~in~ or diene isomer~
of DoMP were detected. The distllled product wei~hed 72.0
g and ~ad a purity of 94% (weight)~ corre~ponding to a ~5%
yield.
EXAMPLE 4
Th~ procedure o~ Example 1 was followedg u8ing
106 g t0-3 mole) of ~ri-n-octyl~mdne and 67.2 g ~0.3 mol~
of ToMP, saturated with anhydrous HCl. After 3 hours of
reac~ion ~ime at 180~190C, the reaction mixture analy~is
~howed 88% (area~ DCMP, 6% trichlorinated olefins, and no
TCMP or diene isomers of DCMP. The dist~lled product
weighed 42.3 g ~ith an assay of 91.4% (weight), for a yiald
of 90.7%.
~4~3~ -
2~
EXAMPLE 5
The procedure o~ Example 1 was ollowed, using
64.6 g (0.5 mole) o quinoline and 112 g ~0.5 mole) of
TCMP, saturated with anhydrous HCi, After 3.5 hour~ of
reaction time at 170-180C, the reaction mixture analysis
showed 92% (area) DCMP and no TCMP, trichlorina~ed olefins,
or DCMP isomers. The distilled product weighed 69.2 g with
an assay of 92.4% (weight) corresponding to 90.0% yield.
EXAMPLE 6
The procedure of Example 1 was followed, using
130~5 g (0.25 mole) of tri-n-dodecylamine and 56 g ~0.25
. 10 mole) of TCMP, saturated with anhydrous HCl. After 5 hours
of reaction time at 181-190C, the reaction mixture analysis
showed 98% (area) DCMP and no TCMP, trichl~ inated olefins,
: or DCMP isomers. A distilled product weighed 34.5 g with
an assay of 96% (weight), corresponding to a g3% yield.
EXAMPLE 7
The procedure of Example 1 was followed, using
72.0 g (0.5 mole~ of ~rl-n~propylamine and 112 g (0.5 mole)
o TCMP, saturated wi~h ~nhydrous HCl. After 2 hours of
reaction time at 173-175C, the reaction mixture analysis
showed 98% (area3 DCMP with no TCMP, trichlorinated olefins,
or DCMP isomers. The distilled product weighed 69.6 g with
-; an assay of 96.3%, corresponding to a 92% yield.
EXAMPLE 8
, The procedure of Example 1 was followed, using
78 g (0.5 mole) of diethylcyclohexylamine and 112 g (0.5
mole) of TCMP, saturated with anhydrous HCl. After 2 hours
of reaction ~ime at 169-174C, the reaction mixture was
analyzed to show 98% (area) DCMP, and no other dienes~ TCMP,
or trichlorinated olefins. The distilled product weighed
70.0 g with an assay o 96.4%, corresponding to a 93% yiPld.
.
~q~'
34~
~ .
-13-
EXAMPLE 9
This example demonstrates the use of the catalyst
tri-n-butylamine hydr~chloride at reduced pressure.
A reaction flask equipped with stirrer, thermo-
meter, condenser, and oil heating bath, and connected
through a dry ice/isopropyl alcohol-coo~ed trap to a water
aspiratora was charged with 95 ml (74 g, ~.40 mole) of tri-
n-butylamine and purged with nitrogen. Anhydrous hydrogen
chloride gas was then added to the flask below the liquid
surface until 30 g (0.80 mole, or 100% excess) had been
10 added. The excess HCl (that quanti~y above the amount
required to form the amine hydrochloride) remained in the
flask, dissolved in the liquid.
During the HCl addition, the temperature had risen
to 94C. Following the HCl addition, 48 g (0.21 mole) of
T~MP (97% pure3 was added rapidly to the system and the
heating was begun by raising the ~emperature of the oil
heating bath to 183C. As the temperature rose, the dis-
solYed HCl escaped rom the reaction mixture. When the
temperature o~ the reaction mixture rose to ~67C, ~he
system was~placed under partial v~acuum of 354 Torx ~absolute
pressurs). The reaction temperature stabilized at 162-163C
as the system refluxed and;HCl gas evolved ~rom the liquid.
The reaction procéeded for 3~1/2 hours,~ring which time
several samples were taken rom the reaction mixture for
analysisO; Each sample was added to a hexane/water mixture,
and a sample of ~he hexane phase was injected~into a chroma-
tographic column. Th~ procedure eliminated the catalyst
from the analysis since the~water phase ex~racted the catalyst
from the mixture~ The results are shown in Table II.
.. . , . , .. , . . . , ... ~ .,
.. . . .... , . ~ . . . .. . ...... ... ~ .. .. :
~,~
~ 7 3
-14-
TABLE II
Product Analyse~
Reaction Product in Area Percents
Time (h~ DCMP Tri TC~æ
0.05 0.5 3.5 96.0
0.6 39.5 23.5 37.0
2.0 97.0 1.5 1~5
2.5 9~.5 1.0 0.5
3.0 ~00.0 0 0
DCMP ~ Dichloro-4-methyl-1,3-pen~adiene
: Tri : Trichlorinated oleflns
TCMP : 1,1,1,3-Tetrachloro-4-me~hylpentane
.
After khe last sample was taken, the oil heatiL~g
bath wa~ lowered and the system was purged with nitrogen.
The reaction mixture was then distilled under a pressure
o~ 0.7 torr as the temperature was gradually increa~ed to
S 140Q'C. A dry ice/i~opropyl alcohol-cooled trap followed
:: by a liquid nitrogen-cool~d trap connected in series were
used to collect the dis~illate. The catalyst rexained in
~he reaction flask and a cloudy oil ~eighing 31.1 g formed
in the dry ice trap. ~o~hing a~ all deposited ln the li~uid
nitrogen trap. The oil in the dry ice trap was dried with
~odium sulfate crystals and fil~ered to give 30.0 g t)f a
pale yellow oil which was~purged with nitrogen for one h~
: hour. A~alysis by ga~chromatography/lass spectrometry
con~inmed:the produ~t a~ dichloro-4 methyl 1,3~penta-
}.5 diene a'c 91.8% by weigh~, corresporlding to 89~0% yield of
.theore'cical~ No other diene was d~tected.
EXAMPLE 10
~hi8 example d~monstra~es the use of a subsurface
nitrogen purge to promote ~he rem~val o~ HCl, u~ing tri-n-
bu~ylamine hydroch~oride catalyst.
~ .
7 3 ~9
~15-
The reaction ~lask of Example 9 was charged with
238 ml (185 g, l.00 mole) of tri-n-butylamine under nitrogen,
followed by 42 g ~1.15 moles) of anhydrous HCl to form the
hydrochloride of the amine. Then 115 g (0.50 mole) of TCMP
was added and the system was heated as before. Although an
aspirator was connected to the condenser at the outlet of
the reaction ~lask; it was run gently such that the system
pressure was within 1 or 2 torr of atmospheric at all times.
When the temperature of the reaction mixture
reached 165~C, a flow of nitrogen was ~egun below the liquid
surface at a rate of 123 ml/min as measured by a calibrated
rotameter. The 'temperature was maintained at this lev~l
without re~l~ for three hours, during which time s~veral
samples were taken and analyæed as in Example 9. The results
are shown in Table III.
BLE III
Product Analyses
Reaction Product in Area Percents
Time (h)
_
0 6.3 12.5 81.2
0.5 43~5 20.0 3602 0.3
' 1.0 64.0 1705 17.5 1.0
1.5 80.0 11.5 6.5 ~
2.0 88~0 ~.5 1.5 ~ 4.0
3O0 94.0 1.0 -- 5.0
DCMP : 1,1-Dichloro-4-methyl-1,3-pentadiene
Tri : Trichlorinated olefins
TCMP : 1~1,1,3-Tetrachloro-4-methylpentane
After the las~ sample was taken, the product was
recovered as in Example g7 to give 73.2 g of a product which
a^nalyz-e-~ as 90~.~ wei^ght'pe~cent'D'CMP, or a yl~ld of 87.5%
of theoretical.