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Патент USA US2410407

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Patented Nov. 5, 1946
2,410,407
~ UNITED srars PATENT orric
‘MANUFACTURE OF CARBAIVHDE
DERIVATIVES
John R. Durland, Nitro, W. Va., assignor to Mon
santo Chemical Company, St. Louis, Mo., a cor
poration of Delaware
No Drawing. Application July'15, 1942,
Serial No. 451,011
- 15 Claims.
1
.
2
The present invention relates to a process of
preparing derivatives of carbamides. More par
ticularly this invention relates to a process of re
acting a mercaptothiazole or selenium analogue
where X is sulfur, oxygen or selenium. Still
more particularly this invention relate-s to a
_ >
'
,
-
The following speci?c embodiments of the in- '
vention are illustrative thereof but not limitative
of the invention.
EXAMPLE I
Into a reactor of suitable capacity ?tted with
a stirrer and re?ux condenser there was charged
10
substantially 110 parts by Weight of technical
(91%) mencaptobenzothiazole (substantially 0.60
molecular proportion), 57 parts by weight of 37%
formaldehyde (substantially 0.70 molecular pro
portion) which had been brought to theneutral
process of preparing N,N' bis(thiazy1thiomethyl)
icarbamides. These compounds ?nd useful appli
In accordance with this invention it has been
discovered that materials having a basic reaction
are valuable adjuvants in the reaction between
the mercaptothiazole, formaldehyde and a car
bamide. For example, it has been found that a
basic substance catalyzes the reaction and reduces
the time of the reaction cycle. While the reaction
may be effected in a suitable organic solvent, as
,
?ltered 1but above a pH of 11 none of the desired
product is formed.
with formaldehyde and a carbamide. By a car
bamide is meant a compound having the formula
cation as accelerators of vulcanization.
an
(Cl. 260-302)
point (pH 7) prior to its addition, and 150 parts
15 by weight of water.
An iron reactor is quite
satisfactory although where desired other mate
rials of construction may be used. Where desired
the charge, instead of the formaldehyde, may be
brought to the neutral point prior to heating,
there [being little or no difference in the amount
of base consumed. The charge was then heated
to re?uxing'temperature for 4 hours after which
substantially 19 parts by weight of urea was added
medium possesses certain economic advantages. 25 together with a suitable catalyst, as for example
5.0 parts by weight of sodium carbonate, and the
One of the particular advantages of this inven
heating and stirring continued for 6 hours. The
tion is that it provides a method for conducting
reaction mixture was filtered hot and the solids
the reaction in aqueous medium. In the absence
treated with dilute caustic soda in a ball mill to
of the catalyst, the yields are low, the product of
inferior quality and difficult to process. However, .30 remove any unreacted mercaptobenzothiazole.
The insoluble N,N’ bis(benzothiazylthiomethyl)
the addition of an alkaline reacting material, as
urea was ?ltered off, and dried. The results from
for example an alkaline reacting salt, to the re
a series of preparations wherein the catalyst was
action medium whether aqueous or organic, gives
varied are summarized in the table below:
eminently satisfactory results. The invention
appears to be broadly applicable to organic and 435
Table 1
for example alcohol, the use of water as a reaction
inorganic alkaline reacting substances and in
cludes particularly alkalies, basic salts/salts of
strong bases and weak acid-s, tertiary amines and
the like.
The manner in which alkaline reacting sub
-‘ Alkaline agent
Parts by
weight
pH of re
action
mixture
Yield,
parts by
weight
.40
stances function to improve the reaction is not '
known and it is to be understood that this in
vention is not limited to any theory or explana
tion of the effects observed. While one effect of
.the preferred adjuvants is to provide a pH which
favors the desired reaction, this is not the only
factor involved since weakly basic salts are satis
factory whereas adjustment to the same pH with
.45
caustic soda gives low yields. However, strong
bases can be used if the pH is kept above a cer-y ,50
tain minimum value. In particular, the pH of
the reaction mixture should be at least 7.5 where
strong alkali is used. A somewhat higher pH
gives a good yield and in “addition provides 'a
Triethanolamine _______ __
so
These results illustrate in striking‘ fashion the
‘product which can be more easily washed ‘and 55 benefit derived from the addition of an alkaline
2,410,407
3
4
reacting material to the reaction mixture. Ob
carbamide and alkaline reagent may be mixed to
gether at once instead of ?rst reacting the form
aldehyde with either the mercaptothiazole or the
carbamide. Results practically identica1 with
those of #14, Table I, were obtained by mixing
the mercaptobenzothiazole, formaldehyde, urea
and sodium carbonate at the beginning of the
reaction. Similarly, the alkaline reagent may
servations were also made as to the physical form
of the products and it was found that sodium
carbonate, sodium bicarbonate, triethanolamine,
lime and trisodium phosphate gave the most de
sirable products as regards physical form. Gran
ular products vwhich could be easily ?ltered and
Washed were produced.
Caustic soda gave a sim
ilar easily ?ltered product providing the pH of
. be added with the formaldehyde and the car
the reaction mixture was kept at about 10. ,Above 10 bamide added after the reaction with the mer
pH 11 no reaction took place.
' ‘captothiazole is complete.
Where desired a
The alkaline agents also have the e?ect of
methylol carbamide may be formed as the ?rst
speeding up the reaction cycle. This is illus
step followed by condensation with the mercapto
trated by experiments in which 0.5 molecular
thiazole in ‘the presence of an alkaline agent.
proportion of (hydroxy methyl mercapto) benzo 15 Where convenient or desirable the reactions may
thiazole and 0.287 molecular proportion of urea
be conducted in the presence of a wetting agent.
were re?uxed in alcohol for varying periods 3of
expedient is of bene?t in the case of thiazoles
ine both with and without 0.06 molecular pro
which possess very low solubilities. Examples of
portion of sodium acetate. The results are sum
typical wetting agents which may be used are
marized below:
20 decyl benzene sodium sulfonate, the sodium salt
Table II
of the sulfate of technical lauryl alcohol, mono
butyl phenyl phenol sodium monosulfonate, di
' Aékglige
prism‘;
N0
Yes
Yes
Hours Product formed
re?ux parts by weight
20
4
5
butyl Dhenyl phenol sodium ‘disulf'onate and
monobutyl diphenyl sodium monosulfonate.
The time of carrying out the reaction is also
25
subject to considerable variation. While’very
75- 3
72. 2
82. 9
good results are obtained after a 6 hour heating
‘
wbenzothiazole, Z-mercapto '?-chlorbenzothiazole,
period the reaction continues although slowly
after. this point.
Other mercaptothiazoles than those mentioned
30
It will be ‘noted that in the presence of sodium
above may be employed in the reaction. Typical
acetate more of the desired product was formed
examples are 2-mercapto 4-methyl thiazole, 2
in 5 hours than was formed in 20 hours without
mercapto-naphtho-thiazole, 2-mercapto G-nitro
the alkaline agent.
EXAMPLE II
35 Z-mercapto 4-m'ethyl benzothiazole and 2-mer
‘capto 4-phenyl benzothiazole. Also correspond
Into a reactor ‘of ‘suitable ‘capacity ?tted with
"ing selenium compounds may be used as for ‘ex
a stirrer and reflux condenser there was charged
ample 2-mercapto benzoselenazole, Z-mercapto
‘G-methyl benzoselenazole, Z-mercapto selena
zole, Z-mercapto G-hydroxy benzoselenazole, 2
‘selenyl 'benzoselenazole, 2-selenyl G-methyl ben
‘zoselenazole, 2-selenyl selenazole and 2-selenyl 6
hydroxy benzoselenazole.
substantially 110 parts ‘by weight of technical
(91%‘) mercaptoben’zothiazol'e (substantially 0.60
molecular proportion) , 571partsby'weight of neu
tral 37% formaldehyde (substantially ‘0.70 mo
lecular proportion) ‘and '1‘50‘parts by weight ‘of
water. The charge "was heated‘to “refluxing tem
Again the present invention is not limited to
'the’spec'i?c examples herein set forth. The pro
portions cited in the examples may be varied
without substantially changing the final result.
‘Other alkaline agents than those particularly
perature for 4 hours ‘and substantially 24 parts
by weight of thiourea'a'nd 5 "parts by weight of
sodium bicarbonate added thereto. 'The heating
and stirring was-continued ~for 6 hours and ‘the
reaction mixture worked up as ‘described in Ex
ample I. A good yield of N,Nf bis(benzothiazyl
thiomethyl) thiou‘re'a was obtained.
"so
an acid reaction, as for example mono sodium
phosphate, are not suitable,
.This invention is limited solely by the claims
‘attached ‘hereto as'part of the present speci?ca
EXAMPLE IlI
Into a reactor of suitable capacity ?tted with
a stirrer and re?ux condenser there was charged
substantially 10 parts by'weight of 2 mercapto di at
hydro thiazole (2-mercapto‘thiazoline) , substan
tially 8 parts by weight of neutral 37% formalde
hyde and substantially 100 parts by weight of
water.
‘mentioned may be used. Obviously salts having
non.
What is claimed is:
1. The method of reacting a compound con
taining-the nucleus
The charge was heated at 95° C. for 4
hours, substantially 2.75 parts by weight of urea to
and 1.0 part by weight of sodium bicarbonate
added, and the heating and stirring "continued
for 20 hours. The hot suspension which ‘had
formed was r/?ltered hot and the solids treated
with dilute caustic soda in a ball mill to remove
unreacted ingredients. The ‘solids ‘were “again
?ltered off and then dried. The product formed
was believed to be N,N' bis(dihydrothiazy1thio
methyl) urea. This product wasfound topo'ssess
good accelerating properties in the ‘vulcanization
of rubber both alone or when activated vIby a
guanidine type accelerator.
It will be appreciated that "the particular pro
cedures described above 'GanI-be varied widely.
For" example ‘theim'ercaptothiazole, formaldehyde,
in which Y and Y’ are ‘selected from 'a-group con
sisting of‘ sulfur‘and selenium, with formaldehyde
and-a compound having the formula
To
jiii-which 'X'is séle'cted‘from the group consisting
of oxygen, sulfur and selenium which comprises
conducting the ‘reaction at a pH of ‘at least 7.5
#but not 'morelthan 11in ‘the presence of'a cata
‘2,410,407
6
lyst comprising a substance having an alkaline
ing a bis-N,N’(2-benzothiazy1 thio methyl) urea
reaction and isolating a product of the structure
from the reaction mixture.
I
XY
All-Y
'
8. The method of reacting Z-mercaptobenzo
.thiazole; formaldehyde and urea which comprises
conducting the reaction at a pH of at least 7.5 but
I
not more than 11 in the presence of a catalyst
comprising a substance having an alkaline reac—
I
tion and isolating bis-N,N'(2-benzothiazyl vthio
from the reaction mixture.
2. The method of reacting a 2-mercaptothia
methyl) urea from the reaction mixture.
9. The method of reacting 2-mercaptobenzo
thiazole, formaldehyde and urea which comprises
zole, formaldehyde and a compound having the
formula
neutralizing any free acidity introduced by the
formaldehyde into the reaction mixture and con
ducting the reaction in the presence of a cata
in which X is selected from the group consisting 15 lyst comprising a salt having an alkaline reac
tion and isolating bis-N,N’(2-benzothiazy1 thio
of oxygen, sulfur and selenium which comprises
methyl) urea from the reaction mixture.
conducting the reaction at a pH of at least 7.5
10. The method of reacting 2-mercaptobenzo
but not more than 11 in the presence of a cata
thiazole, formaldehyde and urea which comprises
lyst comprising a substance having an alkaline
reaction and isolating a bis-N,N'(2-thiazyl thio 20 conducting the reaction in Water in the presence
of a catalyst comprising a member of a group
methyl) urea from the reaction mixture.
consisting of lime, sodium carbonate, sodium bi
3. The method of reacting a 2-mercapto-thia
carbonate, triethanolamine and trisodium phos
zole, neutral formaldehyde and a compound hav
phate, and caustic alkali at a pH of about 10 and
ing the formula
25
isolating bis-N,N’(2-benzothiazyl thio fnethyl)
urea from the reaction mixture.
in which X is selected from the group consisting
of oxygen, sulfur and selenium which comprises
conducting the reaction in the presence of a cata
lyst comprising a salt having an alkaline reac
tion and isolating a bis-N,N’-(2-thiazyl thio
11. The method of reacting 2-mercaptobenzo—
thiazole, formaldehyde and. urea which comprises
neutralizing any free acidity introduced by the
30 formaldehyde into the reaction mixture and con
ducting the reaction in water in the presence of
a catalyst comprising a salt of a strong base and
a weak acid and isolating bis-N,N' (2-benzothiazyl
'
thio methyl) urea from the reaction mixture.
4. The method of reacting a 2-mercaptothia
12. The method of reacting Z-mercaptobenzo
zole, formaldehyde and a compound having the 35
thiazole, formaldehyde and urea which comprises
formula
neutralizing any free acidity introduced by the
formaldehyde into the reaction mixture and con
ducting the reaction in water in the presence of
in which X is selected from the group consisting 40 a catalyst comprising sodium carbonate and iso
of oxygen, sulfur and selenium which comprises
lating bis-N,N'(2-benzothiazyl thio methyl) urea
conducting the reaction at a pH within the range
from the reaction mixture.
of 6-10 in water in the presence of a catalyst com
13. The method of reacting Z-mercaptobenzo
prising a salt of a strong base and a weak acid
thiazole, formaldehyde and urea which comprises
and isolating a bis-N,N’(2-thiazyl thio methyl)
neutralizing any free acidity introduced by the
urea from the reaction mixture.
formaldehyde into the reaction mixture and con
5. The method of reacting a 2~mercapto aryl
ducting the reaction in water in the presence of a
ene thiazole, formaldehyde and a carbamide
catalyst comprising sodium bicarbonate and iso
which comprises conducting the reaction at a pH
lating bis-N,N’(2-benzothiazyl thio methyl) urea
from the reaction mixture.
of at least 7.5 but not more than 11 in the pres
ence of a catalyst comprising a substance having
14. The method of reacting Z-mercapto dihy
an alkaline reaction and isolating a bis-N,N'(2
dro thiazole, formaldehyde and urea which com
arylene thiazyl thio methyl) urea from the re
prises conducting the reac-tionat a pH of at least "
methyl) urea from the reaction mixture.
action mixture.
'
V
6. The method of reacting 2-mercaptobenzo
thiazole, formaldehyde and a carbamide which
comprises conducting the reaction in the presence
of a catalyst comprising a substance having an
alkaline reaction at a pH of at least 7.5 but not
more than 11 and isolating a bis-N,N'(2-benzo
thiazyl thio methyl) urea from the reaction mix
ture.
7.5 but not more than 11 in the presence of a
catalyst comprising a substance having an alka
line reaction and isolating bis-N,N'(2-dihydro
thiazyl thio methyl) urea from the reaction mix
ture.
15. The method of reacting z-mercapto dihy
dro thiazole, formaldehyde and urea which com
prises neutralizing any free acidity introduced by
the formaldehyde into the reaction mixture and
'7. The method of reacting Z-mercaptobenzo
conducting the reaction in the presence of a cata
lyst comprising a salt having an alkaline reaction
thiazole, formaldehyde and a carbamide Which
comprises conducting the reaction in the presence 65 and isolating bis-N,N'(Z-dihydrothiazyl thio
methyl) urea from the reaction mixture.
of a catalyst comprising a salt having an alkaline
reaction said salt being added to a substan
tially neutral mixture of the reactants and isolat
JOHN R. DURLAND.
'
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