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Патент USA US2110499

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- Patented _Mar._ 8,
‘- ‘2,1
I _‘
UNITED’ STATES’ PATENTS OFFICE
'
1‘
2,110,409
'
_-
p
'
'
1 “DEPOLYMEBIZATION or 1mm
-
_
YPOLYACETALS
-
~
Wallace 11. Carothers, Wilmington, harassing
or to E. I. du ,Pont de Nemours a Company,
Wilmington, Del., a corporation of Delaware
No Drawing. Application January 2. 1935, Se- ~‘ '
rial No. 179. _In Canada November 25, 19327. '
-
,
.
v
(01. 260-54)
10 Claims.
_
This invention relates to' new compositions of oxygen atom in the ring/7 It is essentially a
matter, and particularlylto new cyclic acetals and methyl ether of a cyclic hemiacetal.
other products obtained thru the depolymeriza- tion of linear polyacetals.
U. S. Patent 1,837,273 discloses the preparation -
.
: It is to be noted that the word
of certain cyclic acetals by heating an aromatic
"acetals” is used‘ aldehyde with an- aliphatic _ glycol; The pat-‘c
in chemical literature and also in the description
ofvthe present invention in three senses: in as
a generic expression which represents the com
ented products do not have the. large rings char
acteristic of those of the present invention. '
v The above reactionsfor the formation of cyclic
pound derived ‘from the carbonyl grouping such
10 as is present in aldehydes and ketones by replac-
acetals containing 7 or less members in the ring
may be represented by the following equations; 10
ing the carbonyl oxygen with two OR groups
in which R1 and R.2 represent hydrogen or‘ a
v(the R. of the two ORgroups may be one and the
same group in which case a cyclic compound is
formed); (2) as a subgenericexpression repre-
simple or substituted hydrocarbon radical such
as an allgyl, aryl, aralkyl or' alicyclic radical, and
R represents .a hydrocarbon radical such as van
“5 senting the‘ acetals formed from acetaldehyde;
alkyl, aryLaralkyl, or alicyclic radical:
(3) as-a speci?c expression to represent the de?nite chemical individual, diethyl acetal, i. e., the
' H
1_ _ '
diethyl ether of ethylid?ie glycol. The compounds wherein the carbonyl oxygen is replaced
1'
HOOH’OH'OH+R C RHOKH'EH’OJ'H’O
glycol
aldehyde
(IR
20 by one hydroxyl and one OR group are called
hemiacetals;
_
_ "
X
_
I
R! RI
Y
‘This case is a'contin'uation in part of copending
‘
2.
Cyclicacetals as a broad class are not new. .
'/°R
HOOHIOH10H+
’
-
'
—> OOHICH20+2ROH .
\/
, >
3124 (1923)) prepared a number of cyclic'acetals
“1"”!
'
ene glycol, with either acetylene or acetaldehyde.
c . ,
34/ \QR
.
by reacting polyhydroxy ‘compounds, e; g., ethyl-
20
_ cylic acetal
application Serial No. 548,701, filed'July 3, 1931.
Hill and Hibbert (J. Am. Chem. Soc. 45, 3117,
15.
- .
>
.
‘i
U
cyclic metal
I
f “21033.?”
-
-
'
-
'
R
25
-
( When these methods are applied to 1,5-g1yc0l$
More recently Hallonquist and Hibbert (Can. J. . or'hlgher glycols (higher in the Sense that the
'30 Research 8, 129 (1933)) prepared a number-of hydrOXylS are Separated frOm each other by a 30
' cyclic acetals by ‘the interchange method. This chain of more than 5 carbon 01‘ other atoms), the
method consists in heating the glycol with an products are not cyclic acetals but linear con
open chains monomeric acetal whereupon the , densation polymers. The reaction,.using an open
lowerboiling alcohol distills over, leaving the de- chain acetal (interchange method), may be rep
35 sired acetal. The compounds prepared by‘ these
authors were limited to cyclic acetals containing
5, 6, and 7-membered rings.
resented by the following equation, in which R1 35
and 32 have the same meaning-as inthe above
The method is in-
formulas’ 3, represents the number of reacting '
applicable to the preparation of cyclic acetals
molecules of glycol and Metal, and n fepresemsr
,» containing more than 7 members in the ring; in
40 fact, the method/ gives peor yields when applied
to the preparation of the. 'I-membered rings.
an integer greater than ‘our:
,
_
-, '
B1
on
/
>
\ /
When
these methods are applied to higher gly- 3~ <
cols (glycols in which the hydroxyl groups are
separated by a chain of at least '_5 atoms), linear
glycol
/
in poor yield by Helferich and 'Schaier (Ber. 57,
ocrmcmncnocm
’
R‘
.
45
.' +0105)’.
'
‘
11mm- polymm '
“who;
_
aldehyde is used in place of the Open chain acetal
sumable product of this is the methyl lactolide
_
‘
The reaction follows thesame course when an 50 .
with methanol and hydrogen chloride. The pre"
R,
. . . mommies-maniac}:
50 1911 (1924)) by treating“'hydmxynongldehyde
‘
open emu mm
R,
A cyclic hemiacetal seems to have been prepared
40
' [H°(CH*)"°H1=+[
/°\on ] ’ ‘w’
R!
,
45 polyacetals are formed as shown in 'copending ap-
gliiii’tmn serial N°' 178-’ ?led °f even date her?‘
I
but is more men“; to carry out as is disclosed ,
‘
in the copending' application Serial No. 178, ?led
_
Y
5‘ This is a IO-membered ring but contains only one -
of even date herewith. Even when n is 4, Reac
tion 3- predominates. ;
_ ' _
I ..
‘
-
55
bers at least two of which are oxygen), are de~
rived from linear acetals is not a simple'de
'Ihe failure of glycois and acetals (or alde
hydes) to give cyclic structures having more than
'1 members in the ring appears to be charac
polymerization in the ordinary sense.
The re
action consists in depolymerization and poly
compounds. Both glycols and‘acetals (or aide-4 merization, both changes probably being effected
by acetal interchange.
'
hydes) may be regarded as bifunctional‘ com
teristic oi’ all .reactions involving‘ bifunctional
pounds and may react in two. ways: Two mole.
cules may wndense with the formation of a cyclic
compound (Reactions 1 and 2), or many mole10 cules may ‘condense by ‘a chain mechanism to
form a linear condensation polymer (Reaction
3). with compounds presenting the possibility
' The ease of depolymerization and the, relative
' , amounts of distillate and residual superpolymer
. formed vary greatly with different polyacetals.
‘ These differences are indicated in a qualitative l0
‘way in Table I for the various acetals. It is to ’
be noted that all the polyaccta'ls prepared from
of rings of less than 7 members, Reaction 1 or 2 . tetramethylene glycol, ‘including the formals,
isobutyrals, and benzals, are easily depolymerized, ,
occurs almost exclusively; with compounds capa
ble' of giving 7-memhered rings, both types of
reaction‘ take place, whereas with_compounds
I o?ering only the possibility of higher membered
rings,‘R.'eaction 3 occurs practically exclusively.
giving good yields of-monomeric products and
smaller amounts of residual superpolymers. The
depolymerization'does not require the 'use of ‘a
molecular still; simple distillation at atmospheric
This invention has as an object the depolyil pressure may be used.
merization of linear polyacetals with the forma'-.
The linear polyacetals~
derived from glypols, higher than 1,4 show wide 20
tion of ldepolymerization products. A further ob- ' differences in their 'depolymerization behavior.
iect of the invention is the preparation of cyclic depending upon the aldehyde or ketone (or mono- ,
meric open chain acetal) from which they’ are
derived. Thus,. polyformals' are depolymerized
iect is the preparation of odorii’erous compounds with considerable di?iculty. polybenzals some
useful in \the, perfume and analogous arts. ,A .what‘ ‘more readily, and the‘ isobutyrals rather
still further object is thepolymerization of.the_ easily. In general, the more easily a polyacetal
is decomposed the greater the amount of dis-"
monomeric depolyrnerization products‘ of poly
tillate (depolymerizate), and the smaller the’
acetals. > Other objects will appear hereinafter.‘
v30
amount of residual superpolymer. '
These objects are accomplished by the fol
30
There 'is also a .di?erence iii/the nature of
lowing invention wherein depolymerization of '
linear condensation products of acetals to form the distillate (depolymerizate) obtained from
the'various linear polyacetals. ‘The distillate‘
lower molecular weight depolymerization prod
ucts including monomeric-and dimeric polyace- - derived from polytetramethylene formal and
acetals containing at least 8 annular members,
at least two of which are ‘oxygen. A further ob—
talshaving at least 8 annular members of which ’ polytriethylene glycol formal are cyclic mono
at- least two are oxygen, and hydroxyalkyl vinyl‘ mers containing 7 and ll-membered rings, re
spectively. 'On‘ the other hand, the depolymeri
ethers, is carried out by exposing the linear poly
40
acetal to a suitable elevated temperature under
'a suitable pressure, preferably a reduced'pres
zate obtained from’ the other polyformals con
sists largely of the cyclic dimers. The presence
The‘process for-the depolymerization of suit
able‘ linear polyacetals‘ to‘cyclic acetals of at
inter alia, by the odor. The polybenzals yield
both. cyclic monomers and dimers on depolymeri
least 8 ring members, atleast two of which are
zation.
of' monomers in the depolymerizate is indicated,
The ratio of monomer to dimer diifers,
omgen, is similar to that described by Hill and depending upon the particular "polyacetal and
Carothers (J. Am. ChempSoc. 55, 5031 (1933))" ,upon experimental conditions. The polyisobu
tyrals from 1,5 and higher glycols, give a mono
for the preparation of cyclicesters by the de
polymerization of linear- polyesters. A suitable meric distillate which appears to contain but
method consists in heating the linear polyacetal littlecyclic acetal,'but to consist largely of a
fhydroxyalkyl substituted vinyl ether of the gen
to a moderately elevated temperature,. e. g., 150°
' 300° C. in a vessel evacuated to. a low pressure
50
eral formulav HO(CH:)»_OCH=C(CHJ) 2.
_
The polyacetals derived from acetaldehyde,
than 0.1 mm.) , the vessel being provided with a_ propionaldehyde, butyraldehv'de, and heptalde
45
5.0
(less than 2.0 mm. of mercury and preferably less . '
condenseror cooled’ surface placed very close
(less than 5 cm.) to the surface of the heated
hyde give monomeric distillates similar to those
derived from the polyisobutyrals.
‘
_ On the basis of the results obtained with the
55 acetal. , An apparatus of this type is known‘ as
a molecular still. [Suitable examples'of such .ap-, , various polyacetals mentioned in the preceding
paratus are shown in ‘copendi'ng application
paragraph‘ (complete list in'Table I), it may be
February
18,‘ 1933 which
if r
stated that cyclic acetals- (either monomers or
' has issued" as D. 8. Patent 2,020,298 and also - dimers) are obtained from the depolymerization
' Serial No. 657,408, filed
at _J. Am. Chem. ‘sec. 54, 1558 (1932). This. :v of polyacetals in which the aldehyde represented
has no replaceable hydrogen on the carbon atom
treating gives a»dis‘tillate'consisting ‘of mono
- meric and dimeric products ind leaves a residue‘
alpha to the carbonyl group, i. _e., an aldehyde
'(superpolymer) ofhi'gher molecular. weight ‘than having no CH group ammtfto the carbonyl
the 011311131 Wlyacem- The present invention
group.
Formaldehyde, and ‘benzaldehyde are
65’ is concerned with the distillate or. depolymerizate, ' representative of this class. -Aldehydes having
“new “pending application serial No‘ 178" a replaceable hydrogen" atom on the alpha car
Which has ‘issued “'U' 84971352 med of even- ' bon such-as acetaldehyde, isobutyraldehyde, etc.,
date herewith, -is concerned‘ with the residual yield a hydroxyalkyl ‘substituted vinyl ether as
~ " superpolymer.
'Iheheatin? is preferably done
‘in’ thepresence'of .a catalyst such as camphor
sulfonic acid. The molecular still is’a preferred
the‘ chief component of . the depolymerizate.
Data on .the decomposition are given in Table I. 70
The physical-and analytical data, particularly
but ‘not absolutely necessary form oi apparatus. the molecular weights and molecular refractions
From the foregoing discussion‘ it may 'be seen ' given in‘Tables II and-III indicate the depoly
thatthe reaction wherein the macrocyclicace
.75 tals (cyclic acetals of at least. 8 annular mem
-merizate oi‘ the polyformals and the polybenrals '
to be the cyclic monomersand dimers.
The 76
9,110,499
dimers are odorless, crystalline solids;
_
7
-
Q
3
dation with potassium permanganate in‘ accord
the
monomers possess fragrant odors. The macro‘
ance with the unsaturated ether structure. The
cyclic acetals show a tendency to polymerize . physical and analytical data and the molecular
when heated in the presence" of a trace of refractions give further'evidence of the unsatu~
p-toluenesulfonic acid.
-
.
‘
'
rated ether structure.
‘
The monomeric depolymerizate obtained from
polyisobutyrals and similar poLvwetals are
characterized as hydroxy alhl substituted vinyl
-
1
I
‘
_,
-
‘-
.
~
'~
are'in general mobile liquids, distillable under
vacuum, and having fragrant odors. 'I‘he-eyclic
monomer obtained from triethylene glycol ‘formal
/R
no(on,).ocn=o
has a fragrant odor remarkably similar to that
a
15
'
The monomeric products (both the .' cyclic
acetals and ‘the unsaturated ethers) obtained
from the depolymerization of the linear acetals
of triethyleneglyeol carbonate. The monomeric
by their ready hydrolysis by dilute acids to the
corresponding glycol and aldehyde-a character
products obtainedYrom the'linear polymers of
tetramethylene
istic of vinyl ethers, their reaction with phenyl- >
formal and isobutyral
have
strong characteristic odors; that of the'latter
isocyanate, and their polymerization when
treated with catalysts oi the type used for‘ poly
being reminiscent of camphor, menthol‘, and
merizing vinyl ethers, the polymerization taking
eucalyptol.
‘
‘
-
More complete data concerning the“physical
as stannic chloride and iodine. ‘The product properties of the depolymerization products, of
obtained from the depolymerization of poly-' the linear polyacetals are given in Tables I and
“11;. ‘ Analytic data arerecorded in Table III.
hexamethylene isohutyral givesacetone on oxi
20 place at room temperature with catalysts such~
Tamar: I,
.
Poluacetals and their depolymchzatizm products
Depolymerizate
/
~
Ease of de
Pdmm
y-
~
\
merizat on
-
I
Nature _
.
'
.35
I
,
>
Tetramethylene formal ____ ..\--
Ve
Pentamethylene formal
Di
easy c__.__
cult _ *
/= ‘ =
N o. of
Structure
ato
in ring
I
Monomer, a liquid ........... ... ......... .1.-.
7
Dimer, M. P. 45-52‘I O. and monomer ....... ..
16
Hemmethylene formal ...... .. Very di?icu1t-__- Dimer, M. P. 7l—72° O. andtrace monomer--.
Nonamethylene formal..- -_'_ --_-.do..---. ____ .. Dimer, M. P. (til-69° G. and trace monomer--.
Decamethy-lene f
____ _Dimer, M. P. 93-94" C. and trace monomer-..
l8
24
26
Tetradecamethylene formal.
Dimer, M. P. 103.5—l04° C. and trace monomer-
Octadecamethylene formal
b
'I‘riethylene glycol formal.
Monomer, M. P. l8—__20° C
Hemmethylene acetal-...
'40
I
i
.
__
_._
._.
Probably monomer liquid .................
Decamethylene acetal _______ -.
'
»
.
l
.Hexamethylene n-butyral. _ _-.
.._
..- ________ ..
Pentamethylene isobutyral.__. Easy
Hexamethylene isobutyml
Decamothylene lsobutyral_.._--
Hexamethylene heptal....
_--
_ __
Hexamcthylene benzal . . .
. ..
'
"
o
Cyclic- _ - -
Open chain -
do
do
do
.-'_
Hexamethylene ketal..--.
Tetramethylene henzal . . .
11
-.-
Open chain ...... ..
i
I‘etramethylene isobutyral. _ -.
-
_. Open chain ...... __
'
.Elexamethylene propional. _ _ . _
Nonamethylene isobutyral . . _ .
' 34
..
______________ .. Oyclic----
._.?o
6o
..do
do
____ .. -..do ............. _
Poor d- -‘. _ _ _ . _ . .
. . . . -.
'
'
I
........... .. _____________ __
Monomer liquid ............................ ..
_
Decamethylene henzal _______ .-
.Cyclio--..
Dimer, M’uP. 122-124“ C. and monomer
Dimer, M. P. 134-435" C. and
7
do-
I
18
...do
26
a The term “monomer’.' signi?es that the iproduetiias the molecular weight and empirical formula ot a monomer; .
I
,
it does not necessarily imply that the product as an acetal structure. I
50
50
I: The depolymerizate was not characterized
c Monomers distilled without the application of vacuum. '
4 These polymers decomposed to aconsiderable extent during attempts to depolymerize them.
.
Team .11
Physical properties 0! dcpolumerizates o! poluacetals
>
'
' Polymer (source)
60
Nature of product
-
~.
'l‘etrameih?lene formal ___________ ..
Pentament
lene formal
65
Cyclic monomer- .'---.--. Acetal" _.
.-..-do
1 o
ro
ro
dn (in
---
rn
rn
__
'1‘ .
eoamethylene formal.
Trinthylene glycol formal ........ -_
do
‘
ro
Cyclic monomer .... -.--. .-.r o
Hexamethylene
Open chain monomer... Ether...-.
Hexainethylene pr
ah.-.
io
--...do.
K??methylene n-but'yra
K
(in
-....do
Hexanzethylene isobutyral. .'
Nonamethylene lsobutyral
-____r n
cn
Decnmethyione isobntyral ........ . ._..__c o.
Hexsmethylene heptal. .
'
o
75
'
'
Io
Io
-
Cyclic monomer .... ..'-.
Hemmethyiene benzal ........... .-
Cyclic dimer._..'- ...... -. ..-
‘
...-.rlo
Mr
11',‘
d}.
7 ........ _.
nil-117°
8
40- 44°/l1_
16
iii
24
26
as- 60°
93- 04°
34
ll
lot-104°
18- m"
..
5 4310
1.0022. 3.38.
26.34
l. 4200
.____
‘<
_..
.-
45- 60/0. 5
77- 79°l3
7 ...-. ..... ..
.
.
v86%!
'
1.4646
I
0.0036 ch00
4..
61.69
64- 69/19
1112-1739/22
l. 4385 0.932!
1.4500 0.0066
40. 2!‘
46.47
96. 5"}‘2
li7-l22°/l
l. 4560
l. 4685
51.09 _ iii. 59
64. 94
05. t8
l4l°l1
1%[1359/1
'
o.......
.
46- 62°
71- 72°
__
_Aeet~al-...-
_
Caled. Found
ro
ro
-
'i‘etramethylene benzal ........... ..
Decamethylene benzal-
',
do-.. _.-
Tetramethylene isohutyral.
- Cyclic monomer ...... .. Aqetal--...
Peutamethylene isobutyral ....... .. Open chain monomer... Ether.-.-. -
70
7
M. P
‘I
Pept'smeth no formal.._.._.__._. Cyclic dimer
gexamethylene formal. ..-_
on
omethylene formal
Decameihylene fonnal. .
'
-$g£:g Eggs
55
1
l
0. 9016
0. 8012v
I
40.18
47.37
~
70 I'
.
7
........ ..
18
121-124’
.... ..
26
134-135“
.-.-_ :
_
76
2,1 10,499
v
Tsau m '
~ Analytical data ‘for
o! M
.
\
'
'5
.1
Analysis
Polymer (source)
'
'
Nature oi
Probable
mm
mm ?u
-
comma
‘
-
10
Tetrsmethylene iormai _____ __
Pelitslnethylene iormal. _ -
Henmethylene i0
Nonsmethylene lormal.-__
c
Cyclic monomer- _ Aes'tel...
7
B0. 82
do- _ --
8
02. 07
(10---...d0--..
do__-_
10
18
24
02.07
04.0
‘ Q. 77
'
..--_
____ _.
....do _____ __
(10....
H} ' 70.0
'.d0._..
34
Cyclic monomer- _ .-_do. .. -_
11
‘Open chain mono-
Ether-.. ____ ..
74.4
01. 86
'
ma
‘
H
n.
0. I)
‘102
‘
'
rm
'
in.
C
H
10
n.
00. 06
v0. 00
10. 34 ' .... -.
01. 07
10. 70
........ ._
10.34
232
10.8 ‘ 200
11.- 02 . 344
61.70
04.0
I.“
10.46
10.6
11. be
' m
206307
333%
mil!)
11.0
372
. 70-8
12.1
850;“
12.4
484'
74.4
.115
:03
8. 64
00. 07
-
102
31. 00
8. 37
1013”
11. 11 ...'_ _'-
'07. 04
10. 77 ........ __
Heumethylene propional..._
08. 35
ll. 30
168
6. 12
11. I)
440336‘ '
n-butyral____
'20 ‘Henmethylene
'l‘etrsmethylene isobutyrsl-.-
(D. 70
11. 62
172
70. I!
11.06
171:1“
00. 67
. 11. 11
144'
M. 04
11. as
1442142
i1. 30 .... _.
09. 1s
'10. 07 ........ ..
Pentamethylene isebutyral. a '0
08. 36
Kexamethylene isobutyral- _- -»
Nonamethylene isobutyrsL- . ' I‘
our. 10
72. 00
Deumethylene isobutyml. __ - -_do- - _.
Hexameihylene heptal;
.-.__do __________ -_
73. U
72. 00
Tetrsmethylene benzsl.
Cyclic ‘monomer- -
74. 16 “
Hexamethylene benssl-
‘ Cyclic dimer____ ._
76. 72
8. 74 ____ __
75. 74
8. 86
__________ __do_ - .1. ..... ..
77. 80
9. 92
77. 34
0. 70
Decsrnethylene
. 11.- ea
12. 15
as. s:
73. 43
'11. as
1a 27
‘12. 29
13. 15 ____ .-
in
214
74. 80
73. I)
11.07
11. is
7,. so ____ __
73. 34
7. 7!
.... ._
‘Sample had polymerired seine priorto analysis.
10
7
Having outlined above the general principles ~- hot 'ethyl acetate, treated with decolorizing car
bon, and allowed to crystallize. The compound
‘and purposes of ‘the invention, the following
examples are given for purposes of illustration,
but not in limitation:
separated as a crystalline~ powder in spherulites ‘
and melted at 565-57’ C.
'
Example ‘1._—-Hezam'ethulene‘formal __
Twenty grams of hexamethylene'glyco
of dibutyl formal, _and»a piece 01’ p-tolu
It was dried to con- .
stant weight in vacuum at 100° C. and analysed
g.
esul
ionic acid the size of a lentil were‘ heated in
> a Claisen ?ask by means fol a metal ‘bath. Dis
tillation of butyl alcohol set in at _155°- C. The
(C, 58.9; H, 11.7; mol. wt., 2190). Itis soluble‘ 36
in chloroform, benzene, carbon tetrachloride, and
xylene: insoluble in'alcohol, ether, petroleum hy
drocarbons and acetone.
,
Eight grains of the crude material was placed‘
in a 250 cc. modi?ed molecular still and heated 40
The slightly moist '
hours to 200°, C. A current of CO: was passed ‘ distillate (2 g.) had a pleasant, rather eampho
thru the melt during the last'half hour. The raceous odor. Alter crystallisation it melted at
residue was further heated under the vacuum ' 93-94° C. It was the cyclic dimer. '
The residue (super-polymer) . was tough sndJ 45
of’an oil pump at'200-210° C. .for 11/2 hours.
' temperature was gradually raised during 11/2 “ at. 230-250° C.-i'or 48 hours.
I.
.> The PMuct (linear(polyacetal) was a viscous
brown syrup which did not solidify.
.'
'
Five’ grams of the aboye syrupy polymer was
placed in a 250 cc. modi?ed molecular. still and
heated tor-16 hours at>24515° C. under 2 mm. K
- About 0.2 g. of moist crystalline deposit of a,‘
strong min’tyodor collected. on the condenser;
This odor was very similar to that of the dc;v
‘I , polymerizate obtained from hexamethylen'e car-4
55 bonate under similar circumstances.‘ The dis
leatheryand possessed a curious fracture. The
fractured surface was white. and showed fibrous
striations under-a
lens.
.
"
.
.
In‘another experiment 10 g. of the crude linear
polymer was placed in a 50cc. distilling ?ask 50
and heated under vacuum in a' metal bath at
270° C. There/was no result until 0.1 g. o!
FeCh was. added. In 22 hours, 2.1 g. of distilla
(wet dimer) distilled.
.
'llzomple Q3.—Tetrudecamethylene formal
tillate was ?ltered and the crystalline material‘
recrystallized from. 70% methyl alcohol. It f Thirteen and twoetenths'grams oi tetradecam
. crystallized in ?at needles bf M. P‘. 71-72“ C. . ethylene glycol and 10 g. of dibutyl iormal were
andwas the cyclic dimer. The residue was super
.polymeric in character.
I ' Example ‘2'.—-D'ec¢methvlcne formal '
1. Thirty-four and eight-tenths: grams of deca
methylene glycol, 36 g. of dibutyl formal did not
react alone at 200° C. (bath temperature). when
0.1- g. oi FeCla was added, ebullition set in at
165‘ C. The temperature was elevated to 200° C.
. in three hours.‘ C01.was passed through'the
melt the’ last hali hour. Heating was continued
heated together in the usual way with leCl: as
catalyst. The waxy product (linear polyacetal)
' was dissolved. in hot ethyl acetate and treated
with decolorizing carbon. On cooling, the solu- ‘
tion deposited the polymer in the form of a mi
crocrystalline powder. -It was driedin a vacuum
at ‘100° C. for 20 'hours and analysed (C, 73.1%“; ‘
‘H, 12.1%; mol. wt. cryoscopicslly in bensene, ,
‘2480) .
-
.
.
_
.
Five grams oi‘ the crude polymer was placed in
70 under vacuum f for ll/z'hours at 150-‘-‘-200°" C. a modi?ed molecular still and heated, for 30 70
Thirty-six and ?ve-tenths cc. of alcohol dis. hours. Three grams of slightly pasty distillate
tilled (theory 37 cc.).' The residue (linear poly- . with a rather muskyodor collected Recrystab.
ace'tal) solidi?ed on cooling to a light‘ brown
wax, ‘weighing 38.5_ a. Seventeen snd'?ve-tenths
76 grams oi'the residue was dissolved in‘ 150 cc.‘oi'
lized from alcohol, it was odorless and melted at
‘ 103.5-104' C. It was the cyclic dimer.v The resi- .
due’ was superpolymeric in character.
2,110,499
‘
4.
.
,
Erample 4_.—Triethulene glycol formal
, 11'7-122‘I C./1 mm.
,Seventy-?ve grams of triethylene glycol, 84 g.
of dlbutyl formal; and 0.12 g. of camphorsulfonic'
(have the structure
‘l
'
5
Its properties indicate it ‘to .
.
~
nocmigmiicmocnwwmh;
acid were heated together by means of a metal’
Itw had-a viscosity of 0.22 ‘poise (bubble tube)‘ 5
blown thru the mixture the last hour; 89 cc. . which did not change in one i hour's heating at
* "
' of butyl alcohol (theory’91 cc.). distilled. The 984-100“ 0. A trace of petoluene'sulfonic acid
residue (linear polyacetal), a. viscous syrup, was introduced and heating continued one hour at the
same temperature. The viscosity of‘the cooled
heated at 200-250° C. for 3 hours; 57 g. of par
10
liquid was 8 'poises. Further heating did not '10
tially crystalline distillate collected. Most of’ change
this value“;
'' '
a this was lost by polymerization on attempting to
bath at 150-190° C. for 21/2_hours. Nitrogen was
redistil it.
Ezample 8.—-He:rainethylene
The experiment was repeated and a '
sample puri?ed for analysis, by fractional crys- '
tallization. The product-melted at 18-20° C; and
was the cyclic monomer. I It had a mild fragrance
4 much like that of triethylene glycol carbonate.
When it was heated for 1 hour at 100° C. with a
‘
Twenty-nine and ?ve-tenths grams of hen.
methylene glycol, 64_grams of dibutyl heptal, and 15
- 0.1 gram of camphorsulfonicacid were heated
together in the usual way, ?rst at atmospheric
trace of camphorsulfonic acid it polymerized to pressure, then with blowing, and ?nally in 'a
,_ vacuum.v The theoretical quantity of alcohol dis-*
‘20 a viscous syrup. When boiled with dilute hydro
tilled during the ?rst two operations and 45
chloric acid it evolved formaldehyde.
grams of semiésolid distillate of B. P. 120-170°
Example 5.-'-Hezbmemyzene prom'vnaz
C./1 mm.‘ in the last. The liquid was separated,
washed with dilute NazCOa and dried. It was
Thirty-four and four-tenthsjgrams‘ of hex
amethylene' glycol, 59.2 g. of dibutyl propional, then distilled at 1 mm. The largest fraction,‘ 9_
grams, distilled at 129-1'35° C. It was yellow and
' and 0.1 g‘. ca/mphorsulfonic acid were heated to
gether 11/2 hours’ at 150-1900 C. with nitrogen had a very faint pleasant vodor. - Its properties
blowing the last 40 minutes; {>7 cc. of distillate indicate it to be monomeric in character.
Emm?ple 9.—He:camethylene 'Icetal"
collected.‘ The residue (linear polymer), a some
:30 what-viscous light redliquid, was then heated
’ Eighteen and eight-tenths grams of ~dibutyl"30
at; 3mm. and 45.5 g. of. distillate boiling at 81
ketal, 11.8 g. ofhex'amethylene glycol, and 0.05 g.
130? C. (mostly at 116° 0.; bath at 145-215“ C.)
25.
of camphorsulfonicacid were heated together at
was received. The distillate ,was ?ltered from
145-1'70° C. bath temperature for 40 minutes with
2.5 g. of glycol. The ?ltrate was dissolved in ‘ blowing with nitrogen during the last 5 minutes. " '
i ether, washed with aqueous sodiumcarbonate
and water, and the'residue fractionally distilled
at 3 mm.; 11.5 g. came‘ over at 775-79"
It
was‘monomeric in character and its-prop rties‘
indicate it to be the unsaturated ether,- '
.
40,
Practically the theoretical quantity of. butyl al-r'
cohor distilled.
The syrupy residue (linear poly-. '
ketal) was then heated at, 5 mm. pressure up to .
210° 0. bath temperature. Twelve and ?ve
tenths g. of yellow distillate, mostly crystalline,
distilling at 92-130°'C. was collected. iThe‘crys
HOCHz (CH2), 4CH2OCH=CHCH3. v _
material, amounting to 9 g., wassepa
It polymerized to a viscous syrup when heated ‘talline
rated and identi?ed as liexamethylene glycol.
at 100° C. with a trace of camphorsulfonic acid.
The ?ltrate; which possessed a mild ?oral~ frag;
rance, crystallized partially on standing.
. Example 6.—He:ramethy.le1ie isobutyral
Seventy and. eight-‘tenths grams of , hexa
Example 10_.—Tetra\methyiene benzal
" 45
' methylene glycol, 127.2 g. of dlbutyl isobutyral,and ‘
'Twentyéthree and six-tenths g. of tetramethyl- Y ‘
0.1g. of‘ pure p-toluenesulfonic acid were heated :ene
glycol, 31.9 ‘g. of dimethyl benzalpand 0.1 g. of - .
together at_160-\200° C. ~for 5 hours with blow- , camphorsulfonic acid were heated together at _
ing with nitrogen during the last ‘3/; hour; "110 .
cc. of butylalcohol distilled (theory, 110, cc.). _125-140° C. for 30 minutes with blowing with 50
Initrbgen ' during vthe .last ' 10 minutes. ‘ Ninety
The'residue, the linear polyacetal, was a some - four per cent of the theoretical amount of methyl '
what viscous’ light orangeliquid- A sample was‘
alcohol'distille'd; The residue was heated .under > , removed, dissolved in ether, washed with aqueous ' 2 mm. pressure and 41‘ g. of distillate (B. P.v
sodium carbonate and water, dried with potas
sium carbonate, and recovered by evaporation of
the ether. After~drying it was analyzed. Calcd. .
for. CioHzuOa_:C,69.'76%;' H,11.62%; mol. wt. 1'72.
.60
'scopically'in benaene) 7'12; 705‘.
sisted of two phases andhad a ‘strong odor of
tetrahydrofurane. It was. diluted with ether,
washed with dilute Na2co3, dried with K2003 -
and recovered by‘ evaporating the ether. Distilw
l
. The remainder was heated at 1 mm. at 150-190°
.C. and,.'withtheexeepti_on of 3 g. of dark, viscous
residue, distilled. The distillate was dissolved in
ether, washed with sodium~carbonate and water, ,
dried, and fractionated. The main fraction, 50
d g.,' distilled at 96.5 cat 2 mm» There was four
grams of residue. The main fraction (mono- 1’
‘ ' meric) was the unsaturated ether.
lation under.12 mm. yielded two main fractions
'of 10 'g. each with boiling points, of 123-127"
C./12 mm. ‘and 121-1215‘, c./12 mm.
60'
The sec- ‘
0nd was analyzed and was found to be the cyclic
monomer. It had a pleasant odor, reminiscent
of- benzaldehyde.
'
‘
"
'
‘
85
Example 11.—l'iezamethyle1ie benzal
\Thirty-seven and seven-tenths 3.101’: hexal;
nocmkcnh icrhocn=c (CH3) 2.
I Ezagnple l7.-Nonamethylenelisobutyral'
99‘-~100° C.) was collected. The distillate con 55.
‘ ‘ methylene glycol, 50 g. of" dimethyl benzal; and
’
Linear polynpnamethylene isobutyral was pre-'
0.1 g. of camphorsulfonic’ acid were heated tor, 70
gether in the usual way for ' 30 vminutes at
ll5-160° C'. with blowing with nitrogen at the _
‘end; ‘(The dimethyl benzal "was prepared ac
cording to Voss (Ann. 4855, 283 (1931) from di
tion, it yielded‘ a monomeric Cproduct boiling at .1_net,hyl_ sul?te, benzaldehyde, and methyl alco
pared in a manner analogous to that usedi‘with
.hexamethylene' isobutyral. 0n depolymeriza-.
.
.
~
'
_
(
hol.) Methyl alcohol distilled (86% oi’ theory). depolymerlzation products) listed below, includ
The residue (linear polyacetal) was heated under * ing for comparison a few, simple cyclic acetals pre
pared by the usual method (glycol plus aldehyde)
2 mm. for one hour at 170-220’ C. ,Very little
were sealed in tubes (5.5 mm. inside diameter) to v
distilled.‘ The residual polymeric product con
sisted‘of 62 g. of a light yellow.rvery
a depth 01' 6.5 cm. with a 4.5 cm. air space above
syrup
the surface. The tubesin which the. tormals
', of faint benzaldehyde odor.
-
Nine g. of polymer wererplaced in a small -_were polymerized were 4 mm. in diameter (in
side? ?lled to a depth of 6 cm. with a'3.5 cm. air -
molecular still heated by the vapors of alpha
chlorodiphenyl, B. 1?. 268’ C. and heated for ‘7
space above the liquid. Two tubes were made of
every compound, one tolbe kept pure as a blank, 10
hours under 0.5 mm. Five and ?ve-tenths I. of
the other catalyzed by the addition oi’ a thin ?ake
semi-solid distillate collected. "The solid 'phase
otf camphorsullonic acid about 1 mm. square.
was ?ltered and, after two crystallizations from
The times oi.’ ?ow of the liquids on inversion of
the tubes we're measured at the outset and at the
end of each period of heating. The tubes were 15'
.falcohol, gave needles which melted at 122-1210
C. lt'i‘was the cyclic dimer.
_.
,
The ?ltrate was dissolved in ether, ,washed
with dilute NazCO: and dilute NaHSQudt'iBd:
always allowed to stand at 25° C. for several hours
before the measurements were made.
‘ over KzCOs, and recovered by distillation. of the
The
catalysed samples were heated with results as
ether. It was._ then put in a small modi?ed
molecular still ?tted with a drip cup and heated
follows:
-
.
.
5
Ethylene isobuturalv (cyclic acetal with 5‘
20 one hour up to 90° C. maximum. 1 Five drops of
20
‘distillate collected. .It was a mobile liquid with‘ a ‘ m'embered ring) .-1.4 sec. at start; no change
after 11% hours at 100° C. and then 3 hours at
pleasant odor resembling benzaldehyde and was
the cyclic monomer. ‘Anal. Calcd. for CuHnOz:
‘ C, 75.72%; H, 8.74%. l'bilnd: C, 75.80%; H.
9.16%.
.
[150°
C.
‘
~
'
p
-
'
'
'
Trimethylene isobutvral. (cyclic acetal with 6
membered ring).—l.4 sec. at start; no change
after 11% hours. at 100° C. and then 3 hours at
'
I The residue increased-in viscosity during the
distillation and ?nally resembled the original
polymer. Anal. 'Calcd. for (com-om: C,
75.72%; H, ‘8.74%. F0und:-C, 73.78%; H, 8.73%.
150° C.
‘
-»
Tetrsmethylene isobutural (a cyclic acetal
with 7-membered ring. derived from de'polymeri
zation‘vot polytetramethylene iso'butyral).—l.4
Emmple .1Z.--Decamethulene benzat
sec. at start;' slightly .more viscous after 2%
Twenty-six grams of decamethylene glycol, 24' hour;_ 8 secxafter 5% hours} 5 sec. after 6%
hours‘; 12.5 see: after 11% hours at 100' C. and
1 hour at 150° C.; 12.0 sec. after 11% hours at
g. dimethyl benzal, and 0.06 g. oi’ camphorsul
. i'onic acid .were heated together as in the previous
' preparation. Eighty-three'pe'r cent oi’_ the theo
100°C- and 3 hours at 150° _C. I
~1
'
35
Monomeric depolvmerisation product of ‘poly
retical' amount of methyl alcohol distilledu' The
product, obtained in almost theoretical yield, was
pentamethulene "isobutvral
.
a pale yellow, very'viscous syrup with little odor. Nine and ?ve-tenths grams was heated for
12 hours at 230-240“ C. in a modi?ed molecular
still’ ?tted with adrip cup. About 7 cc.-distilled. 2.2 sec. at start; 5.0 sec.§after 1 hour at 100° ‘C.;
Two-tenths gram of a solid phase was removed 135 sec. after 2 hours at v100' C.; l min. 25 sec.
and recrystallized iromalcohol. It separated as after 4 hours at 100° C.;v l min. 21 sec.- atter v8
needles and melted at 134-135° ,C. __It was the -
45
cyclic dimer.
_
hours at 100° c.
.
'
'
-
’
Monomeric depolumerization Product of ‘poly 45
i
The liquid distillate was diluted with benzene ‘ hezamethylene- isobuturai
washed with dilute NaHSO: and NaiCOs, dried
withKaCO': and recovered by distilling the solvent
‘ , at low temperature.
Distillation was carried out
in.a ?at type Hickman molecular still at 0.5 mm.
up to 100° C. bath temperature. About 1 cc.
came over before the liquid residue, originally
'
2.0.sec. at start; 26 see. after 15 min. at 100' C.; 60
50 sec.; after 2% hours at 100° C.; 2 'min,-30 sec.
aiter,8% hours at 100° C.; 8 min. 45 sec. after
quite mobile, became very viscous and distillation l3% hours at 100? C.; almost immobile after
ceased. The distillate had a mild pleasant odor, 17% hours at 100°C.
[Monomeric depolumerizatm product of poly55 not unlike benzaldehyde.’ ~'l‘he ready’ polymeriz
abllity of the residue and the analysis of the dis _ nonamethylene isobutwraL-See Example 7.
Trime'thulene formal (cyclic acetal with 6
tillate indicate it to be ‘impure monomer. Anal.
Calcd. for CrIHssOs: C, 77.86%; H, 9.92%. Found: .membered ring) .—4.5 sec. at start; no change
vc, 75.59%; x, 12.06%.
‘
.
after 2 hours at 100° C. and then ‘1% hours at
'
,The monomeric depolymerisation products or.
linear‘polyacetals, which linear polyacetals have
a unit length oi’ atle'ast silht atoms, may be
polymerized by heating, preferably in the pres
ence c! is polymerisationdcatslyst such as cam
phorsulionic acid. The following example indi
cates the polymerization. oi’ the‘ monomeric de
polymerila’tion products, of linear
of
unitlengthofatleasts'. ,Depolymerisationplod
uctiofpolyacet'als'otunitleng‘thlessthanaa‘re
70 included for purposes of comparison:
. _
50' C.
-
T
_
Tctramcthulene formal (cyclic acetal with 7
membered ring) .—4.5‘ sec. at start; no
e
after 2 hours at 1009 C.; 35 see. after 2 hours at _
‘100° C. and 30 min. at 150' C.; almost immobile
after 2 hours at 100° C., and lwhours at 150' C.
‘ Pentome?wlene formal’ (cyclic acetal with 6
memberedring) .—4.5 sec. at start; 13 see. after 2
hours at. 100'_ C.; 16 see. after 2 hours at 100' C.,
and 30min. at 150° C416 see. after 2 hours at
100’ C_., and 1% hours at 150‘ C.
_'
.
'
-
Tetrameth?ene bonsai (cyclic acetal with 'l- '
ring).—4_.5 sec. start: 30sec. alter
. ' .Iasmple
M
13.—Polmtioa ol
.
15‘
“Marmot liner rolnccloh
Samplesot a‘. various mm ‘(mm-uric
.
vl
'
100 sec...a!ter 4
hours at'roomtemperature; did not incresseon
‘2,110,409?
-
-
I
'
'
' 7
/
reaction appreciable but low enough to avoid any
It is to be_noted that'cyclic acetals containing
seven or higher vmevm'bered rings underwent poly-.
thermal decomposition. The use of temperatures’
over 300'.’ C. is not advisable.- In many cases the
amined polymerized readily.
_
.
f
'
linear polyacetals can be depolymerized by con
v The depolymerization of the linear polyacétalsi ventional distillation methods; this is true for Cir
is not limited \’to the use of the polyacetals cited ' the polyisobutyrals mentioned in Table I. The
depolymerization of certain polyacetals may start
in the foregoing tables and examples. Poly
\
acetals may be derived from other glycols, for at ‘temperatures as low as 90° C.
example, diethylene glycol, heptamethylene gly- ..
The cyclic monomersmay be polymerized under .
10 col, dipropylene glycol, octamethylene glycol, " varying conditions. Polymerization may be car 10
merization. All the unsaturated
ethers
ex
alpha-'methylpentamethylene glycol, octadec'a
' ried out between 75' and 200° C. for extended
methylene glycol, dodecamethylene glycol, tri
periods.~ Catalysts such as camphorsulfonic, ben
zenesulionic, ,p-tolu'enesulfonic, and other ,sul
tonic-acids, aluminum'chloride, stannic chloride
decamethylene glycol, 1,3-xylylene alcohol, 1,4
xylylene \alcohol, etc. The aldehydes (or
.
'ketones), represented in the polyacetals are not
restricted to those present in the polyacetals
mentioned in the examples. As examples of
arc of advantage.
The polymerization may also
be' carried'out in solution altho in general more
slowly.
Interpolymerization rwith . other
heat
polymerizablematerials may be eifective. The
the‘followlng are mentioned: propionaldehydep polymers may be used in coating, impregnating,
’ other 'aldehydes and ketones which may be used,
phenyiacetaldehyde, trimethylacétaidehyde, ani-J
adhesive, etc.,compositions. 7'
none, acetophenone, etc. The ‘cyclic acetals- de
employed.
The new cyclic acetals of the‘ present inven
'
impregnating, adhesive, etc., compositions.
30
The process of the present invention. affords a
method for the synthesis of macrocylic acetals
which cannot be prepared by. any other method
wherein R2 and Ft3 are hydrogen or monovalent
tertiary hydrocarbon radicals and R1 is a divalent _
thus far developed. These compounds generally
organic radicai; and preferably a divalent hydro
carbon;\having at least 5 annular atoms between
have fragrant odors rendering them ‘useful in
the preparation of perfumesi Through the ‘selec
the two oxygen ‘atoms.
.
.
~.
‘
I
tion of the proper polyacetal, the process of the
-
present invention aifords a method for synthesiz
. Ferric chloride; p-toluenesulfonic acid, and
Mv
nic chloride, antimony chloride, aluminum chlo
ing hydroxyalkyl substituted vinyl ethers. The
substituted yinyl ethers are formed in a liquid ~10
phase reaction which is simpler than the. vapor
phasereaction for the preparation of substituted
ride,,boron tri?uoride, and hydrogen chloride it
vinyl ethers from linear monomeric acetals as
camphorsulfo'nic acid have been mentioned as
catalysts for the preparation and depolymeriza
tion of the polyacetals.
'
Per- '
oxides, stannic chloride, aluminum ‘chloride,
iodine, etc., catalyze the reaction which may also
‘be carried out in solution in ordinary solvents.
Interpolymerization with vinyl esters,~~metha
cryl'ic esters,.-unsaturated ketones, etc., may be“
effected. The polymers may be used in coating,
class new products not obtainable by methods
tion may be represented by the formula
'
(circa 25° C.) up to approximately 200° C.
rived from the 1-5 glycols or higher are as a
,25 heretofore
;
The open chain monomers maybe polymerized
at ‘temperatures ranging from‘ ,room temperature
sic aldehyde, . methyl ethyl‘ ketone,‘ cyclohexa-'
Other halides, e. g., stan
self may be employed as well as other sulfonic
described in the literature. The vinyl ethers may
acids,such as benzenesulfonic acid, xylenesulfonic . '
be converted into (resins useful as adhesives, im
pregnating agents, and incoating compositions .
and plastics.
acid, etc. Acidic compounds in‘ general function
as catalysts. ‘Thus, magnesium sulfate and potas
sium acid sulfataare .useful. Itis desirable how A.‘ ‘Where the statement is made with respect to
ever, to ‘select a catalyst "which is mild in its an atom A that it is‘ ‘falpha” to another atom B, _.
' .. action. andadoesinot cause excessive darkening o'r _it is meant that A and B are ‘directly joined to
decomposition. The sulfonic acids are particu-' each other. Where the atom A is “beta” to/B
.larly suitable.‘ With, 'an acetal’ of acidic proper»v it is attached directly to an atom which is in turn
ties, such as a chloro acetal, itisoften-unneces- -
attached directly to B.
sary to add a catalyst in the preparation of the‘
polyacetal. In the depolymeriza‘lg‘lonof ‘the poly
acetal, a catalyst is likewise oftenunnecessary.
.
' .
The above description and examples are‘in
' tended to be illustrative only. Any modi?cation
' ‘of or variation therefrom which conforms to the
The conditions for the depolymerization of the spirit of the invention is intended to be included
linear polyacetals may be varied’. While the ‘use within the scope of the claims.
of a molecular’still for this‘ transformation is in
60
I claim:
. .
60
many cases preferable, an inert,gas or organic ’
1.,A-dimeric cyclic acetal of a glycol having a
. yapor may be passed thru the moltennlinear poly-. chain of five to eighteen atoms between the hy-A
mer with or without the use of reduced pressure _ droxyls, with an aldehyde of the formula RZ‘CHO.
to carry away the volatile products; The " re- '
- action may also be carried out in a solvent with I
wherein R2 is selected from“ the class ‘consisting
of hydrogen and monovalenthydrocarbon ‘radi
or without the addition of catalysts with arrange-v . cals wherein the carbon attached to the carbonyl '
' (CO) group is‘ attached only to carbon atoms.
amentsfor distilling‘. and returning the solvent
after separating, the volatile products of the re
'_action distilling with it. In certain cases the
‘process may be'effected by using powerfully ad- _
sorbent» materials, ‘such as silica gel, adsorbent '
‘carbon, activated alumina, etc., to 'bring about
the‘irreversible adsorption of the volatile reaction
» products. The reaction may be carried out at a
temperature high enough to make the rate of
2. Cyclic triethylene glycol formal.
3. A cyclic‘ acetalof thev formula .
ire-ch \al
.
_0
wherein R3 is selected from the class consisting,
2,110,490
of hydrogen and monovalent hydrocarbon radi
7. Cyclic'iormals oi the formula
cals wherein the carbon attached to the acetal
'
i
ncé\ A\al
o
.
/
0
\o
' grouping is attached onlyto carbon atoms and
10
R1 is a divalent organic radical having a chain
oi’ the to eighteen atoms between the acetal
oxygens.
,
V
6
acetal ‘
o
v
10
,
4. kcyclic acetal of the formula,
'
lu-crr
v.
carbon is carbon, RF is selected from the clam
1/°-\:
‘
-
wherein each atom in the beta position to the
consisting of hydrogen and monovalent hydro
carbon radicals and R1 is a divalent organic radi
' R1
cal having a chain 01' live to eighteen atoms be- [15
' wherein each
atom in the beta position to the
acetal
-' (°’ ')
'20
i
v
\o
tween the acetal oxygens and is selected irom
the class consisting of divalent open chain hydro;
carbon radicals, xylylene radicals, and divalent
radicals consisting of a plurality of divalent'open
chain hydrocarbon radicals ;oined through ether 90
-
7
carbon is carbon, R.1 is- selected from the class
consisting~ of hydrogen and monovalent hydro
oxygen.
carbon radicals and R1 is a divalent organic radi
cal having a chain of ?ve to eighteen atoms be- ‘.
tween the acetal omens and is selected from the
class consisting of divalent open chain hydrocar
bon radicals, xylylene radicals, and divalent radi
30 cals consisting. of a plurality of divalent open
chain hydrocarbon radicals joined through ether
oxygen.
.
~
'
i
' 8. Cyclic iormals of the formula
-
'
'2
4.70
'
»
.
_
wherein R1 is a divalent open chain radical con
sisting 01‘ a plurality of divalent open chain hydro-_
carbon radicals Joined throughc ether oxygen.
,0
9. Process for the preparation oi’ cyclic acetals
oi’the
formula
J
,
,
-
>
‘
g 5. Cyclic benzals of the formula
moan-ca" a1‘
36
a
r
\o/
.
wherein R1 is a divalent organic radical having‘
wherein each atom beta toithe mm
a chain oi live to eighteen atoms between the
40
acetal oxygens.
_
.
'
/0
'
6. Cyclic benzals of the tormurla
‘
_
»
o-
‘
>
‘40
,
carbon is carbon, R" is selected irom the class
consisting of hydrogen“ and monovalent ‘hydro
carbon radicals and R1 is a divalent organic radi
. wherein R1 is a divalent organic radical having a
chain of 5 to 18 atoms between the acetal oxygens _
and is selected from the class consisting of 'di
valent open chain hydrocarbon radicals, xylylene
radicals and divalent open chain radicals consist
ing oi’ a plurality of divalent open chain hydro
carbon radicals joinedthrough ether oxygen.
cal having ‘a. chain of five to eighteen atoms be- 45
tween the acetal oxygens, which comprises de- ,
polymerizing the corresponding linear polyacetal
by heating the same at low pressure and isolating ’
and purifying the depolymerization product.
10. ‘The process of claim 9 wherein a sulfonic 5.)
acid catalyst is used.
'
‘
N
.
‘WALLACE H. CARO'I‘HIRS
n
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