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Патент USA US3076859

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United States Patent O??ce
Patented Feb. 5, 1963
3 976 85%
This invention involves the discovery that o-alkyl thio
phenols may be produced in substantial yield by direct
nuclear alkylation of thiophenol and its homologs with a
selected secondary alkyl-generating ole?n in the presence
of boron tri?uoride-phosphoric acid complex under pre
scribed alkylating conditions. This invention provides
means for producing ortho-substituted alkyl thiophenols
by a direct nuclear alkylation process which is adaptable
to commercial exploitation.
Martin B. Neuworth, Pittsburgh, Pa, assignor to Consoli
dation t-Coai Company, Pittsburgh, Pa, a corporation oft‘
No Drawing. Filed Nov. 21, 1960, Ser. No. 7il,425
8 (Ilairns. (Cl. 26tl--6ti9)
This invention relates to alkylated thiophenols and 10
processes for preparing them. More particularly, it re
lates to a process whereby ortho-alkyl thiophenols are
Under selected ring-alkylating conditions, t-alkyl
generating ole?ns, e.g., isobutylene, can be made to
nuclearly allrylate a thiophenol. However, the t-alkyl
prepared by direct nuclear alkylation of a thiophenol in
group will substitute in the para position only. If this
the presence of boron trifluoride-phosphoric acid com
position is blocked, ortho substitution will not take place;
plex as catalyst.
15 only sul?des, i.e., thioethers will be formed.
The problems involved in the direct alkylation of thio
In accordance with this invention, an alkylatable thio
phenols are well known. As has been pointed out in
phenol containing an ortho position that is “free,” i.e.,
unsubstituted by other than a hydrogen atom, is converted
US. Patent 2,753,378:
to an o-alkyl thiophenol in substantial yield by reacting
“In contrast with phenolic compounds which are simply
alkylated to produce alkyl phenols, previous eifects to
alkylate thiophenols have resulted in alkylation exclusive
ly of the sulfur atom with resulting production of aryl
it with a secondary alkyl-generating ole?n under ring
alkylating conditions in the presence of boron tri?uoride
tempted alkylation of thiophenols has also been compli
alkylation is determined by the selection of the thio
phenol, the ole?n, and the specific reaction conditions.
phosphoric acid complex as catalyst so that there occurs
substantial substitution by the secondary alkyl group in
alkyl sul?des. Since e?forts to eiiect carbon alkylation of
‘thiophenols in the past have resulted in the production
the ortho position. Further, in accordance with this in
of aryl alltyl sul?des, it has been necessary to resort to 25 vention, it -is also possible to obtain nuclear dialkylation
in the event that both ortho positions are unsubstituted.
means such as zinc dust reduction of allryl benzene sul
In addition to ortho-substituted mono and dialkyl thio
fonyl chlorides, the reaction of diazotized alkaryl amines
phenols, S-alkyl thiophenols are also obtained. These
with hydrogen sul?de, catalytic hydrogenation of aryl sul
sul?des or thioethers may be quantitatively converted to
fonic acids and the action of sulfur on Grignard reagents
in order to produce alkyl-substituted thiophenols. In ad 30 the corresponding thiophenols using a sul?de-cleavage
technique. The product distribution obtained by the
dition to the tendency towards thioether formation, at
cated by the fact that common alkylating catalysts such
as anhydrous aluminum chloride and concentrated sul
furic acids have tended to cause desulfurization and con
densed ring formation at relatively mild operating condi
It has been reported in the prior art that thiophenols,
The use of low temperatures is particularly favored.
Suitable alkylating agents include non-branched ole?ns,
e.g., propylene and cyclopentene.
The propylation re
action generally gives highest yields, with higher ole?ns
giving lower yields of ortho-substituted ring-alkylated
products. In general, non-terminal linear ole?ns, e.g.,
can be directly alkylated in the para position by using 40 Z-butene, give poorer results than their terminal isomers,
e.g., l-butene. It is noted that the by-product sul?des
a combination of a speci?c alkylating agent, namely,
cannot be isomerized by further reaction in the presence
either a tertiary aliphatic alcohol or a tertiary aliphatic
of boron tri?uoride-phosphoric acid complex. This iso
mercaptan, together with a speci?c catalyst, namely, an
merization technique is effectively used for converting
aluminum halide catalyst, e.g., aluminum chloride, Pri
including ortho- and meta-substituted alkyl thiophenols,
mary and secondary alcohols are considered unsuitable 45 tertiary S-alkyl thiophenols to corresponding para-alkyl
as alkylating agents in that sultur-alkylated products are
ated thiophenols. However, the sul?des formed in the
reported to be produced exclusively.
present process may be quantitatively converted to the
corresponding starting thiophenol or o-alkyl thiophenol by
Relatively little information is available in the chemical
literature with respect to the preparation of orthosubsti
using any of various thioether cleavage techniques, e.g.,
tuted alkyl thiophenols. None of this information relates 50 reaction in the presence of either sodium metal in liquid
to the direct nuclear alkylation of thiophenols in the ortho
ammonia, alumina-silica, or solid phosphoric acid. Ef
position. Heretofore, to obtain o-alkyl thiophenols, other
than o-thiocresol and possibly o-ethylthiophenol, relative
ly expensive and involved techniques were required,
conversion of a thiophenol to a nuclearly substituted
which made the processes of little or no commercial in
55 the process of this invention of direct nuclear alkylation in
terest. In one such method, the corresponding o-alkyl
analine derivative is converted to the o-alkyl thiophenol
the ortho position with subsequent sul?de cleavage.
fectively, then, in accordance with this invention, total
ortho-alkylated product may be obtained by combining
Speci?c sul?de cleavage processes are disclosed and
by the relatively elaborate Leukart synthesis. In another
claimed in the following copending applications: M. D.
method, the o-alkyl benzene sulfonyl chloride is converted
Kulik and M. B. Neuworth, S.N. 94,164; R. J. Laufer,
to the o-alkyl thiophenol by a standard acid~metal reduc 60 S.N. 94,163; and R. I. Laufer and M. B. Neuworth, S.N.
tion. The preparation of the starting materials for these
94,161; all ?led March 8, 1961, and assigned to the
reactions is further frequently involved and expensive.
assignee of the present application.
Accordingly, it is an object of the present invention
The terms “alkylation” or “alkylating” as used here
to provide a method, free from the disadvantages of
in, unless otherwise indicated, are directed to the sub—
known methods, for directly alkylating a thiophenol in the 65 stitution of a primary or secondary alkyl hydrocarbon
ortho position of the ring.
radical for a hydrogen atom in one or more ortho posi
It is an additional object to provide orthoalkylated
tions of a thiophenolic compound. The term “C-alkyla~
tion” is speci?c to substitution in the ring, and “S-alkyla
It is still a further object to provide orthosubstituted
tion” refers to substitution of the hydrogen atom attached
alkylated thiophenols in high yield by utilizing the process 70 to the sulfur atom to form an alkyl aryl sul?de, i.e., a
of this invention in conjunction with thioether cleavage
The alkylatable thiophenolic compounds that are em
ployed as startingfma'terials in the process of this inven
ring positions. Problems of steric hindrance, which ordi
70,424, ?led of even date herewith, boron trifluoride is
a catalyst that may be used to effect the ring alkyla
tion of thiophenols in the ortho position. On the other
hand, phosphoric acid is wholly ineffectual in this re
narily occur when an attempt is made to substitute a
gard, no C-alkylation occurring. However, the catalyst
tion contain a hydrogen atom in at least one ortho posi
tion. Alkyl substituents may be present on the remaining
group onto the ring in a position adjacent to another
used herein, namely, boron trifluoride-phosphoric acid
group already on the ring, are of relatively minor import
complex, has been found to be signi?cantly more effec~
.ance compared with similar problems which occur under
tive than either boron tri?uoride (or phosphoric acid)
conditions of para alkylation. Thus, propylation of m
in giving a much more complete alkylation in the ortho
thiocresol can 'yield signi?cant amounts of both possible 10 position of the ring in a single pass of reactants through
ortho mono-isopropyl derivatives; as well as of the 2,6
the system. At the same time, the high pressuresre
diisopropyl derivative, whereas t-butylation of m-thio
quired for effective use of gaseous boron trifiuoride-are
cresol is not feasible using isobutylene.
not required for use with the boron triffuoride-phosphoric
Thiophenol homologs that may be advantageously em
acid complex because of its liquid nature.
ployed in the process of this invention include, for exam 15
In addition, the catalyst used herein is insoluble in
ple, o-thiocresol, m-thiocresol, p-thiocresol, m-ethylthio
the alkylated thiophenol reaction products, and there
phenol, 2,3-, 2,4-, 2,5-, 3,4-, and 3,5-thioxylenols, 4-t
fore may be readily recovered from the system by simple
butylthiophenol, and 4-t-butyl-o-thiocresol. In general,
decantation and effectively reused. Reuse of boron tri
thiophenol, itself and thiophenol substituted only by
?uoride is ordinarily impracticable because recovery of
lower alkyl radicals (C1 to C5 are preferred as alkylatable 20 the gas from a pressurized system is difficult, and separa—
starting ‘materials.
These preferred alkylatable thio
tion of the gas from other evolved gases may be required.
phenols arle unsubstituted by other than hydrogen in either
or both ortho positions on the ring.
Recovery of other catalysts, e.g., aluminum chloride,
vfrom the reactant system is not feasible because of their
_ In ‘general, secondary alkyl-generating unsaturated
ready solubility in the thiophenols. As a consequence,
aliphatic hydrocarbons having from 3 to 12 carbon atoms, 25 a catalyst such as aluminum chloride‘ ordinarily is de
-e;g., various ole?ns and ole?n polymers, are suitable and
stroyed during the subsequent hydrolysis step and there
preferred for the practice of this invention. Particularly
fore cannot be recovered for reuse. Thus the catalyst
useful are C2 to C5 ole?ns. As the molecular weight of
of this invention is uniquely adapted to the alkylation
the-ole?n employed increases, yields of ortho-substituted
ring-alkylated product ‘decrease. Suitable alkylating
agents that may be used for obtaining substitution in the
ortho position of the ring include propylene, l-‘butene,
2-butene, l-pentene, and cyclopentene.
‘It is considered an essential feature of‘ this invention
of thiophenols in the ortho position of the ring because
of its high activity in effecting ring alkylation in the ortho
position, the absence of high pressure requirements and
its ready recovery and reuse.
The catalyst of this invention when prepared from 85
percent phosphoric acid, i.e., containing 15 weight per~
that boron tri?uoride-phosphoric acid complex be used 35 cent water, the phosphoric acid of commerce, will effec
as catalyst together with a secondary alkyl~generating
tively promote ring alkylation of a thiophenol. How
‘ole?n to effect the direct nuclear alkylation of the thio
ever, it has been uniquely found that superior results are
phenol in the ortho position. The catalyst of this in
obtained in the ring alkylation of a thiophenol when the
_vention1is' essentially an equimolar reaction product of
catalyst is prepared starting with 100 percent phosphoric
boron tri?uporide and phosphoric acid. This product is 40 acid. Using-this latter catalyst, considerably higher yields
*a’cl'ear, amber-colored liquid.
of ring-alkylated thiophenol are obtained.
For obtaining ortho-substitution of a secondary alkyl
The liquid catalyst used in the practice of this inven
group into the ring of a thiophenol, so-called conventional
tion may be prepared by various methods known to the
'alkylation catalysts are not substitutive for each other.
art. Thus the catalyst may be conveniently prepared by
Thus, catalysts which are effective in a Friedel-Crafts 45 bubbling boron tri?uoride gas through 100 percent phos
reaction with respect to ring-alkylating phenols, e.g., zinc
phoric acid. An equimolar complex results which be
chloride, antimony 'trichloride, sulfuric acid, phosphoric
gins to decompose at temperatures above 120° C. If
1 acid, and ferric chloride, are essentially ineffective for
a de?ciency of boron tri?uoride gas is used, then free
the ring alkylation ‘of thiophenols in either the ortho or
phosphoric acid is associated with the catalyst complex.
’ para ’ position.
Temperatures between about -50 and +50° 7C. may
be successfully employed in the practice of this invention.
The use'of temperatures below 25° C. is preferred to
irnini-mi‘ze sul?de formation. Where reaction rate con
' siderations permit, 'temperatures'between '—25 and —50°
C. are-lconsidered particularly effective for obtaining
maximum nuclear alkylation. 'At temperatures between
'75 and 100° C., which are ‘considered optimal for para
v‘alkylation, little or no ortho alkylation is obtained. An
amount of 5 to 10 percent of catalyst, based on the
‘original Weight of the thiophenol, is generally preferred
for obtaining optimum yields. However, amounts of
‘catalyst ‘between 3 and 25. percent by weight are con
50 If an excess of boron tri?uoride gas is ‘added, under
pressurized conditions, the gas will go into solution in
the complex, and subsequently be evolved from the liquid
upon release of pressure. If 85 percent phosphoric acid
is used, water will be present in the ?nal complex.
The process disclosed herein vis particularly advan
tageous for commercial exploitation inasmuch ‘as the
alkylated thiophenol may be completely converted to
the ortho C-alkylate product with no S-alkylate product
present. The S-alkylate product formed generally con
60 sists of the sec-alkyl aryl sul?de and also of the sec
alkyl o-sec-alkaryl sul?de. The formation of the latter
sul?de is favored when a molar excess of alkylating
agent is used. Where both ortho positions are initially
sidered‘ suitable'depending upon speci?c reaction condi
free, other sul?des will also be formed. In contrast to
' tions.
65 the isomerization of sul?de, which is effectively used in
Because of the relatively rapid rate of the ortho alkyla
the para alkylation reaction, in the present process the
tion reaction and the low temperatures at which it is
by-product sul?des are cleaved to form their correspond
preferably carried out, ‘degradation of the thiophenol by
ing thiophenols. ‘This cleavage may be accomplished by
"the catalyst is not a serious problem. However, the cata
reaction of the sul?de withsodium in liquid ammonia
‘lyst ofthis invention is unique in that it does not detectably 70 or by heating over alumina~silica catalyst or ‘over solid
degrade 'the‘thiophenol itself even at relatively elevated
phosphoric acid, e.g., phosphorus pentoxide absorbed on
an inert carrier such as kieselguhr, commercially avail
v"A catalyst-of ‘this invention is essentially an equimolar
able as UOP No. 2 catalyst.
‘complex of boront-ri-?uoride-and phosphoric acid. As
Without being restricted by the reaction mechanism
pointed out in my joint copending application, Serial No. 75 to be suggested, it ‘is believed that the high ortho se
lectivity of the reaction, combined with the promoting
It is noted that in accordance with the above two re~
effect of low reaction temperatures, suggests the involve
actions, the ?nal product obtained is either a mono- or
ment of the ole?n and the thiophenol in an intermediate
di-ortho alkylated product, or convertible thereto. These
reactions are speci?cally illustrated in the following ex~
complex in the vicinity of the sulfur atom. The e?ect of
low temperatures is apparently to increase the stability
of the complex. In contrast to para alkylation, it is be
lieved that little or no nuclear alkylation or migration
of the sul?des occurs. Thus recycling of the sul?des
in the presence of catalyst is ineffective for increasing
amples relating to the alkylation of thiophenol by l-bu
tene in the presence of boron tri?uoride-100% phosphoric
acid complex as catalyst:
Example 1
the yield of the ortho-allrylated thiophenol because of 10
the absence of isomerization phenomena. It is believed
that once all the ole?n has been absorbed by the system,
Thiophenol, 4.53 moles, was reacted at 25° C. with
the reaction is essentially complete. An increase in re
8 moles of 1~butene in the presence of 20% by weight,
action time beyond this point should not therefore sig
based on thiophenol, of BF3—H3PO4 catalyst. The l
ni?cantly affect the ?nal product distribution.
15 butene was introduced into the thiophenol catalyst mix
Depending upon speci?c reaction conditions with re
ture at the rate of 2.5 g./min. After introducing all of
spect to alkylatable thiophenol, alltylating agent, and
the ole?n, the reaction mixture was held at 20° C. for
2.5 hours.
temperature, a reaction time of as little as half an hour
may be suitable. In general, reaction times between 2
The following results were obtained.
and 3 hours are preferred. Under optimum conditions
Conversion of thiophenol: 61.9 mole percent.
of temperature and of catalyst concentration, as well as
Weight percent
optimum ole?n to thiophenol ratio, the reaction is rapidly
completed. An increase in the reaction time beyond three
hours will then give but little increase in the yield of
2-sec-butylthiophenol ___________________ __ 22.9
Sec-butylphenyl sul?de ___________________ __ 15.3
o-alkyl thiophenol. Apparently, the ?nal product dis 25
tribution is rapidly attained, even at low temperatures.
Sec-butyl 2,6-di-sec-butylphenyl sul?de _____ ..._ 24.3
The alkylated thiophenols, both C-alliylated and
Example 2
S-alkylated, ?nd a variety of uses. They are particularly
useful as substantially odorless rubber peptizers. Several
of these compounds or their metallic salts are of interest 30
((2) Reduction of isopropyl o-isopropylphenyl sul?de
as lubricating oil additives because of their antioxidant
using sodium metal in anhydrous amm0nia.-Isopropyl
and detergent properties. As antioxidants, they serve to
o-isopropylphenyl sul?de (60.5 g.) was dissolved in 250
prevent resin formation in fuels; condensed to form thio
milliliters of ammonia maintained at its atmospheric re
acetals, they are particularly suited as additives for high
?ux temperature, —33‘’ C. Sodium metal was added in
pressure lubricating oils; they are also useful as additives 35 small pieces until an excess was present as determined
for metal cleaners to protect the metal from atmospheric
by a ‘blue coloration of the solution. The addition of
attack; they also protect drying oils, such as linseed oil,
from darkening and oxidation; they have also been used
to stabilize preparations of adrenalin and other hormones.
sodium occurred over 11/2 hours, with reaction of a half
hour following the addition. After destruction of excess
sodium and evaporation or" ammonia, a residual solid
Various of the S-alkylate compounds are seen as possess 40 was recovered and dissolved in 100 ml. of water. The
ing useful insecticidal properties in addition to being use
aqueous solution was washed with ether, acidi?ed, and
ful as ready sources for the production of the correspond
the product extracted with ether. From the ethereal solu
ing thiophenols.
tion was recovered 38.8 g. o-isopropylthiophenol.
For purposes of illustration, without limiting its scope,
(b) Reduction of isopropyl 2,6-diisopropylphenyl sul
the process of this invention will be particularly de 45 ?de using sodium metal in anhydrous ammonia.—-Isopro
scribed with reference to the conversion of thiophenol
pyl 2,6-diisopropylphenyl sul?de (48 g.) was reacted with
to o-sec-butylthiophenol. The following reactions, shown
sodium metal in anhydrous ammonia as described above.
schematically and not stoichiometrically, illustrate the
Thirty grams of 2,6-diisopropylthiophenol was ?nally re
manner in which conversion of thiophenol to o-sec-butyl 50 covered. This represented complete conversion of the
thiophenol may be obtained under preferred reaction con
starting sul?de and recovery and product of the yield of
75 percent.
Reaction 1.—Sec-butylation of thiophenol
©—0H(0H9O2Hi oirmonano
CHUJHa) 02115
(c) Cleavage of isopropyl o-isopropylphenyl sul?de
tuted in an ortho position of the ring which comprises
alkylating an alkylatable thiophenol containing a‘ hydroi
using solid phosphoric acid catalyst.—lsopropyl o-isopro
gen atom in ‘an ortho position with a monoole?nic hy
drocarbon containing fro-m 3 to 12 carbon atoms and in
pylphenyl sul?de (150 g.) was heated at a temperature
between 295 and 3250' C. in the presence of 20 g. solid
which the alkyl substituent formed is a secondary alkyl
group, in the presence of boron tri?uoride-phosphoric
acid complex ‘as catalyst at ring alkyla-ting conditions so
that there occurs substantial substitution by the second
ary alkyl group in an ortho position.
phosphoric acid catalyst and a high boiling paraf?n oil.
The parai?n oil serves to increase the temperature at
which, thesul?de may be re?uxed, at atmospheric pres
sure. After reaction for ?ve hours‘ under controlled re
?ux conditions in a packed column, followed by ?nal
removal ofpot and column holdup under reduced pres
sure, a distillate was recovered.
3. The process for preparing alkyl thiophenols alkyl
ated in an ortho position which comprises alkylating a
thiophenol selected from the class consisting of thio~
phenol and lower alkyl-substituted thiophenols having an
This distillate. was re
fractionated, to yield the following products:
unsubstituted ortho position on the ring with a mono
‘Yield, mole
percent (based 15 ole?n containing from 3 to 12 carbon atoms and in which
on 78.5% con
the alkyl substituent formed is a secondary alkyl group,
version of
in the presence of boron tri?uoride-phosphoric acid com
plex as catalyst at ring alkylating conditions so that there
7. 7
11. 5
Isopropylphenyl sul?de;
6.- 0
6. 5
Thiophenol ............................. ._
63. 1
p-Isopropylthiophenol ___________________ -_ I
(i. 0
6. 2
occurs substantial substitution by the secondary alkyl
20 group in :an ortho position.
4. Theprocess for preparing’o-sec-butyl‘thioplienols
which-comprises reacting a thiophenoloontaining ah'ye
(d) Cleavage of isopropyl 2,6-diisoprapylphenyl sul?de
using solid ‘phosphoric acid as catalyst.—-—I'sopropyl 2,6
diisopropylphenyl sul?de (139 g.) was heated .in the pres
mo-noole?nic butene in the presence of boron tri?uoride
ence of 20 grams of solid phosphoric acid and, 140 grams
tions: whereby- :substantial carbon butylation-pinanortho
of‘ high boiling para?in oil essentially as described above.
The following products‘ were recovered:
drogen atom inan ortho position with an-unbranched
phosphoric acid complex as catalyst atalkylating- condi4
5. The process for preparing o-secibutyltthiophenols
which comprises reacting a thiophenol‘containing a hy-'
drogen. atom in anortho positionwithan unbranched
monoole?nic butene in the presence of from 3 to -25.per§
Yield, mole
percent (based
on 79% con
centrby weight, based on-starting thiophenol,‘ of'boron
tri?uoride—l00% phosphoric acid complex 'as'catalyst at
.version of‘
initial Sul?de)
a temperature between —50 and +50° C.‘ whereby'subi-j
Thiophenol ............................. -_ ..
Isopropylphenyl sul?de ___________ ..
35 stantialcarbon butylationrin an ortho position occurs.
0-_Is0propy1thiopheno1 _________ ._
9.15- ;
p-Isopropylthiophenol ________ __
s'opropyl isopropylphenyl sul?d _
2. 1
6. 6 '
3. 0
6. The process of substituting the hydrogen atom in an
ortho position .of a thiophenol by a secondary alkyl group
Diisopropylthiophenol 1 ......... ._
and obtaining substantially all C-alkylate product‘which
7; 3
comprises reacting a thiophenolcontaining a hydrogen
1 Major isomer present was 2,6-diisopropylthiophenol..
40 atom in 1 an. ortho position with a monoole?n containing
from Ste 12 carbon ‘atoms and in which the alkyl substié
tuent formed ‘is a secondary alkyl group, ‘at ring alkylat
ing conditions inthe presence of boron tri?uoride-phosr
out departingirom the spirit and scopethereo'f, which
are primarily‘ directedto, the direct alkylationof, an 45 phoric acid complex so that the reaction mixture obtained
includes substantial amounts of ortho C-alkylate product
alkylatable thiophenol in the ortho position 'iIl‘gthe‘ pres
in addition to ,S-alkylate products selected from the class
enceof boron .tri?uoride-phosphoric acid complex-as cat-.
Obviously many. modi?cations-and. variations; of the
invention, as-jhereinbefore set forth, may be made-With
alyst jusing -a;secondary alkyl-generatingole?n ,as' alk'ylat
consisting of.secialkyl-o-sec-alkaryl sul?de. and sec-alkyl
objects. thereof. and the: aprended. claims.
Ilcts from respective S-alkylate products.
aryl sul?de, and cleaving the S-alkylate products in the
ing agent. Specific details and procedures , given, , there:
fore, 1 should-‘be considered only - illustrative of. the inven 50 presence of a sul?de-cleavage catalyst to form o-sec-alkyl
thiophenol and~ the starting thiophenol as cleavage prod
tion, its-‘,scopebeing determined, in. accordance with, the
which comprises ralkylating an alkylatable thiophenol
7. The process according to claim 6 wherein there:
generated star-ting thiophenol is recirculated in the
'8. The process,.according to claim 6 wherein said
containing a hydrogen atom in an ortho position with a
monoole?n is an nnbranched butene.
I claim:
1. A process of substituting the hydrogen atom in an
ortho position of a thiophenol by a secondary alkyl group;
rnonoole?nic hydrocarbon ralkylating. agent, in which. the
alkyl substituent formedis a secondary alkyl group, in
the presence of boron tri?uoride-phosphoric; acid com~ 60
plex as catalyst at ring alkylating conditionsso that there
occurs substantial substitution by the secondary alkyl
group in ‘an ortho position in addition to S-alkylation.
2. The process for preparing alkyl thiophenols substi
References Cited in the ?le ofthis patent
Nickels _____________ __ Aug. 17, 1954
Peters ______________ __ Mar. 20, 19.56
Mottern et al. ________ __ July 23, 1957
?atent No . 3'O76,85O
February 5, 1963
Martin B“ Neuworth
It is hereby certified that error appears in the above numbered pat
ent requiring correction and that the said Letters Patent should read as
corrected below.
Column 1,
line 20, for "effects" read -- efforts —-;
column 3, line 20, for "(C1 to C5 are" read ----.(C1 to C5)
line 40, for "trifluporide"
line 28, for "C2" read —~ C3
—~ trifluoride
Signed and sealed this 24th day of September 1963;
Attest: '
Commissioner of Patents
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