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Патент USA US2405019

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July 3o, 194s.
G. A. DALIN
PROCESS OF MAKING ORGANO
2,405,019
SILICON COMPOUNDS CONTAINING A C~SI BOND
Filed Oct. 5, 1943
Patented‘July 30, 191%
2,405,019
. UNITED A.STATES PATENT 'oFElcE
2,405,019
PROCESS OF MAKING ORGANO-SILICON
COMPOUNDS CONTAINING A C-Sl BOND
'George A. Daun. nemers. Conn., assig‘nor to Flax
Corporation, Hartfor ,‘Conn., a corporation of
Delaware
Y
Application october s. 19'43. sensi No. sesgos-i
5 Claims. (Cl. 260-807)
'I'his invention relates to the synthesis of
of time, and, in fact, probably react at every
organo~silicon compounds containing a C-Si bond.
collision.
It has particular relation to organic substituted
Activation can be effected in various ways, such
silicon halides, that is, silicon halides in which
as by the use of high temperature, electrical dis
from one to three halide atoms are replaced by
a corresponding number of organic radicals or
groups and having the general form
charge, in the presence oi’ one or more of the reac
tants. ultra-violet light, and by the introduction
of rapidly moving particles, such as alpha and
beta particles, and hydrogen and chlorine atoms.
I have also found that the rate of reaction can
where R is an organic radical or group, a carbon
atom of which is bonded directly to Si. X is a 10 be increased by the use of suitable catalysts in the
reaction zone. Examples of catalysts are silver,
halide bonded to Si, and a=1 to 3.
iron, copper in the form of metals or oxides ad
Such compounds are useful as intermediates
sorbed in activated carbon.
for -the synthesis of various products, such as
A preferred form of the invention comprises
silicon resins, and in making heat transfer liquids
activating vapors of a hydrocarbon and of a sili
impregnants, adhesives, coatings, insulation ma
con halide by means of thermal energy. To ac
terials and lubricants.
complish this the vapors may be passed through
The general object is to provide a novel process
a suitably heated furnace such as an electrically
of making such compounds more cheaply, and
eiilciently, and safely than they can be made by s heated quartz tube. To increase the total con
20 version, the unreacted portion of the materials
prior processes.
may be recirculated. The vapors may be suit
Heretofore these compounds have been made
ably replenished with the reactants in order to
principally by the well-known Grignard reaction.
keep the composition of the reaction mixture
In this reaction, organo-magnesium halides in
constant. The condensate may then be sub
ether solution must first be prepared, which are
subsequentlyfadded to silicon tetrachloride. Very 25 Jected to fractional distillation to separate the
organo-_silicon reaction products.
~
careful control of the temperature and reaction
velocity is required. Several illtrations must be t
If an evaporative process is used, the concen
trations of the _reactants are selected to give the
carried out under conditions requiring the exclu
sion of O2. CO2 and H2O, followed by vacuum dis 30 proper ratio thereof in the vapor phase with due
allowance for differences in vapor pressure. The
tillation of the complex mixture of reaction prod
ucts.
rate of ilow of the reactants, the pressure in the
apparatus and the temperature of the hot tube
The principal disadvantages in this process
when carried out on a commercial scale are:
or furnace, as Well as the composition of the
1. Relatively high cost of the alkyl and aryl 35 reaction mixture, are controlled toregulate or
halides.
,
inñuence the reaction. The reaction can be car
ried out at reduced pressure in which case air
2. Diñlculties and dansers in handling the large
should be removed and prevented from entering
quantities of extremely reactive, corrosive and
the apparatus. The reaction zone may be heated
_
The Grignard reaction also is undesirable as 40 to a temperature of approximately 840° C. to
1060° C. or higher. Lowertemperatures may be
the basis of a commercial process because it can
used when a catalyst is employed.
be run only as a batch process.
In order to conduct the reactants through the
I have discovered that if suitable hydrocarbons
apparatus and to insure that air and oxygen will
and silicon halides are passed in the vapor phase
through a. zone wherein they are activated, the 45 be excluded, I prefer to use an inert carrier gas
fo'r the reactants'. Nitrogen is suitable for this
synthesis of organo~silicon compounds, in which
purpose. The carrier gas should be freed o1' oxy
carbon is bonded directly to silicon, occurs. 'I'his
gen and moisture bypassing it through a suit
activation consists in imparting energy as rota
inñammable materials.
tional,> vibrational, electronic or translational
able purifying and drying train before admitting
energy to one or more oi the reactants, and thus 50 it‘to the apparatus. The apparatus should be
prepared before starting operations by passing
increasing the concentration of reactive mole
cules. y
the carrier gas alone or with reactants there
If sumcient energy is imparted, dissociation
' takes place, with
the formation of free radicals
i in the Vapor phase. These fragments are so reac
tive that they can exist for only very short periods
through. This may best be done before the reac
tion chamber is heated up. All joints and con
nections must be air-tight and so constructed that
55 the reactants will not be contaminated by foreign
matter such as lubricants.
9,406,019
`
f
4
stitution to form a mixed compound, such as
I have employed three principal methods to
pass th’e- reactants throughthe reaction sys
phenyl methyl silicon dihalide. The release of
methyl groups from aromatic compounds typi
tem. Figure 1 shows schematically, the sequence
of' operations involved in 'any of these methods.
provisions for variation in these operations be
ing indicated.
iled by toluene may be facilitated by the presence
of chlorine in the ortho or para positions. An
examplefoi such compounds is ortho-, or para
chlorotoluene.
‘
Hydrocarbons containing tertiary carbon atomsÑ
. Method No. 1.-Vacuum- transfer
may be used in'v carrying out my invention to
The raw materials, ii liquid, are placed in the
reservoir, or reservoirs, which may be heated. 10 take advantage o! the high degree of reactivityj
The pump is connected into the line and started 4 oi hydrogen atoms bonded to such carbon atoms.
up, evacuating the system back to the reservoir. ' Examples of such hydrocarbons are isobutane and
cymene.
The contents of the reservoir are permitted to
To form- methyl silicon halides, methane and
evaporate and to pass (with or without pre
heating) into the reaction chamber, through the 15 ethane as well as other volatile paraiiln hydro
carbons may be used, particularly highly
condensing system and into the separating sys
branched hydrocarbons which have more methyl
groups. Methane, for example, dissociates .to
keeping the composition of the liquid in the
form methyl groups and hydrogen atoms. Each
reservoir such that, according to well-known
principles of evaporation, the composition oi the 20 ethane -molecule dissociates into two methyl
groups:I Methane or ethane may also be used
vapor will be that desired.
to form >mixed compounds.~ Thus. the silicon
Method No. 1-A
tetrahalide ilrst may be reacted with methane
and then with benzene to form phenyl methyl _
In order to increase the rate oivevaporation
silicon halide or these reactions may be carried
and, i! desired, to dilute the reactants, a 'carrier
out simultaneously to obtain the same product.
gas is passed through the contents of the reser
> The preferred silicon Itetrahalide employed as
voir. thus becoming laden with'the vapors of the
tem.
Suitable arrangements can be made for
reactants.
’
areactant is silicon tetrachloride.
~
‘MethodîNd Zn-Carrier aas
An ihert carrier gas, such as nitrogen, is passed
through the reservoir. The system may be main
tained at any pressure from atmospheric up to
that at which the carrier gas is supplied. The
.
Benzene is
preferred to form phenyl substituted silicon com
30
pounds.
Also, it is preferred to use a hot tube as the
means for activating the reactants.
In forming aryl-silicon compounds from ben
zene and silicon tetrahalide according to my
use of a vacuum pump is not'required.
35 novel process valuable by-products, such as di
phenyl. also may be formed. The amount oi di
Method No. 3.-Fzasn boiler a
phenyl formed may be increased -by increasing
The reactants are pumped into a ñash boiler,
the ratio of benzene to silicon tetrahalide in the
and being given no opportunity tocondense be
reactant mixture.
fore reaching the reaction zone must pass 40
through it in the vapor phase.
250 ml. of a solution containing silicon tetra
chloride and benzene in the proportions of 100 to
130 parts by weight was placed in an evaporator
Method No. sea-Flash boiler wimÍ carrier gas
The ñash boiler method may be used in com
bination with a carrier gas.
l
_
In the event that the hydrocarbon is a gas,
it may be admitted to the reaction chamber,
with or without preheating.
Example I
45 havin-g air-tight connection with an electrically
heated quartz tube. The tube was heated to 840°
C. and nitrogen passed through the solution at
the rate of about 1/_2 liter per minute in accord
The drawing indicates provision for irradiat
ing the chamber with ultra-violet light, heating
ance with Method No. 2 described above.
excited particles which may be used separately
rated and passed through the tube. The reaction
or in combination.
products were collected in a dry-ice trap and then
The
system was maintained at atmospheric pressure.
the chamber, and for the admission of various 50 In about 61/2 hours all the solution ywas evapo
`
Although the drawing indicates apparatus for
distilled up to 85° C. at atmospheric pressure.
practicing all of the methods described above, it
The residue was distilled at a pressure of approx
will be understood that variations and changes 55l imately 19 m. m. and'fractions were collected as
may be made in the apparatus indicated in the
follows: 11o-130° C., 30% of distillate collected;
drawing without departing from the invention.
130-140°, 10% of distillate collected; 140-170" C., i
The conversion may be increased by connect
30% collected: and 17o-175° C., 30% was col
ing a separating system' (scrubbing towers,` still,
lected. The 'distillation range of this last frac#
etc.) between the discharge end of the reaction 60 tion at thegpressure indicated corresponds closely
to that~of diphenylsilicondichloride. The follow
chamber and its inlet end so that unreacted'
vapors or gas may be separated from the end
ing is a comparison of an analysis of this fraction
products and passed again through the zone of
with the calculated composition of diphenylsili
reaction. The converted materials may be drawn`
condichloride.
65
out oi the separating system and fractionated.
The hydrocarbon to be used is selected accord
Diphenylsili
Fraction at
condiohlorido
ing to the organic radical or radicals to be sub
17o-175° O. calcmmd
stituted for the halide atoms oi the silicon tetra
halide. To effect aryl substitution an aryl com
pound is used. Thus benzene may be used to
effect phenyl substitution.> Other examples of
aryl compounds are naphthalene, anthracene,
iiuorene, phenanthrene, indene and diphenyl.
Aralkyl compounds may also be used. Thus,
toluene may effect both phenyl and methyl sub- ~
Percent
Percent
3.
28.
l1.
56.
'â a F
..
lI
..00.
:sses:
.97
0
.00
9
asna.
5
2,405,019
Eœample II ,
43.7 grams of silicon tetrachloride and 56.3
grams of benzene (which evaporates to give a ra
tio of approximately 1:1 in mols in the vapor
phase) were placed in an evaporator and con
nected to a reservoir containing 68.5 grams of
silicon tetrachloride and 31.5 grams of benzene
for replacement of the evaporated reactants.
Using the technique of Method No. 1, the react
ants were evaporated and passed through the
quartz tube at 850° C., at a pressure of approxi
mately 50 mm. The reaction products were con
Example VI
700 ml. of S1014 and approximately 8 cubic feet
of cthane were passed through a stainless steel
tube at 1030° C. in 49 minutes, using Method No.
3A. 'I'he tube was packed with a catalyst similar
to that in Example V. The products were col
lected in brine-cooled xylene.
Fractiona1 distillation yielded a. fraction, boil
ing between 32.4° C. and 56.0° C., and a second
fraction boiling between 65.3° C. and 75.0° C., as
well as'unchanged silicon tetrachloride.
The ñrst fraction appeared to consist of te
densed and distilled up to 88° C. at atmospheric
pressure to remove traces of silicon tetrachloride
and nearly all the benzene. >The residue solidi
tramethyl-silicane, trimethylsiliconmonochloride
ñed on cooling and was identified as a mixture. of
methylsilicon trichloride and dimethylsilicondi
chloride.
andV silicon tetrachloride. The higher boiling
fraction on analysis proved to be a. mixture of
aryl substituted silicon halides and diphenyl.
From the foregoing it will be seen that I have
Example III
provided a. novel process whereby organo-silicon
The procedure of Example II was repeated at 20 compounds may easily and continuously be pro
a pressure of 45 to 55 mm. which was found to lbe
the optimum range for fog formation in the hot
tube. The temperature of the tube was 960° C.
The fog was white at 45 mm. and brown at 55
mm, The optimum pressure varied considerably
de ending upon the stage of reaction. After
ev porating and passing about 250 ml. of solution
through the tube, the collected condensate was
distilled up to 85° C. Following this, three frac
tions were collected at a pressure of 45 mm.: A at 30
duced from raw materials which are plentiful and
of low cost.
Having thus described my invention. what I
desire to claim and secure by Letters Patent is:
1. A process for the preparation of organo
silicon compounds which comprises reacting an
inorganic silicon halide with a hydrocarbon While
both reactants are in the vapor phase at a tem
perature of not less than approximately 840° C.,
condensing the reaction products. and separating
240°-260° C.; B at 260°-360° C.; and C at 360°
organic substituted silicon halide from such re
480° C. (all temperatures uncorrected). Quanti
action products.
tative analysis of fraction C veriñed the presence
2. A process for the preparation of organo
of phenyl substituted silicon chloride compounds
silicon compounds which comprises reacting an in
and by-products, such as diphenyl.
35 organic silicon halide with a hydrocarbon while
both reactants are in the vapor phase at a tem
Example IV
perature of from 840° C. to 1060° C., condensing
90 ml. of benzene and 90 ml. of silicon tetra
the reaction products, and separating organic sub
chloride were evaporated and the vapor mixture
stituted
silicon halide from such reaction prod
passed by evaporation through the hot tube once
ucts.
.
at 980° C. The condensate was distilled to re
move silicon tetrachloride and 20 ml. of toluene
added and removed by distillation leaving a resi
3. A process for the preparation of organo
silicon compounds which comprises reacting an
inorganic silicon halide with a hydrocarbon con
due which solidified. Quantitative analysis
taining a tertiary carbon atom while both re
showed that the main product was triphenyl 45 actants are in the vapor phase at a temperature
siliconmonochloride.
of from 840° C. to 1060° C., condensing the re
Example V
y action products, and separating organic sub
stituted silicon halide from such reaction prod
850 ml. of SiC14 and 5% cubic feet of methane
ucts.
were passed through a stainless steel tube at 960° 50
4. A process for the preparation of organo
C. in 63 minutes. in accordance with Method No.
silicon compounds which comprises reacting an
3A.
«
inorganic silicon halide with an aromatic hy
The tube was packed with a catalyst prepared
drocarbon while both reactants are in the vapor
as follows:
A ten per cent solution of ferric ammonium Ul u phase ata temperature of not less than ap
proximately 840° C., condensing the reaction prod
alum was prepared. Activated carbon in 4 mesh
ucts, and separating organic substituted silicon
granular form was soaked in this solution and
halide
from the reaction products.
ammonia was added until strongly basic, The
5. A process for the preparation of organo
carbon was washed by decantation until the wash '
water was neutral. The catalyst was dried at 60 silicon compounds which comprises reacting
silicon tetrachloride with benzene while both re
110° C. for 16 hours and charged into the reac
actants are in the vapor phase at a temperature
tion tube.l In bringing the tube to 960° C., a
of from 840° C. to 1060° C., and separating the
small amount of water was evolved and removed.
organo-silicon products resulting from the re
The products of the reaction were absorbed in
xylene and fractionated. .A fraction distilling be 65 action.
tween 61° and 69° C. was collected and analyzed.
GEORGE A. DALIN.
It proved to be fairly pure methylsilicontrichlo- .
ride.
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