Note: Descriptions are shown in the official language in which they were submitted.
106672Z
This invention relates to a two step proce~
~or preparing polyols rrOm cyclic acetal-aldehyde com-
pounds.
Processes ~or the production o~ alcohols ~rom
acetals have been disclosed heretorore in the art. For
e~ample~ U.S, patent 2,888,492 issued May 26, 1959 to
Fischer et al. discloses the conversion o~ an ethylenic
aldehydo into a polyol having a carbinol gXouP in place Or
the carbonyl group and containing a hydroxyl group linked
to at least ono Or the carbon atoms Or the ethylenic group
Or the starting aldehyd~ by acctal rormatlon, weak acid
hydrolysis and hydrogenation.
In the proces~ Or this invention, howover,
organic compounds eontaining one si~-membered
acetal ring and one aldehyde group are ~irst
.:
hydrogenat~d st sn elevated temperature in the presence Or
,
a catalytic amount o~ a hydrogenation catalyst to prepar~ -
the corrosponding acetal-alcohol ~hich i~ then simultaneously
hydrolyz~d and hydrogenated ln an aqueo w medium in th~
presence o~ hydrog~n and a hydrolytic a~unt o~ a strongly
acid water lnsoluble ion e~change resin and a catalytic
amount o~ a hydrogenation catalyst to ~orm the corre~ponding
polyol8. I~ desired, the hydroly~is-hydrogenatiQn reaction
may be al'o~ed to continu~ beyond the ~ormation o~ the
,i . .
~ polyol to achie~c cyclization o~ any polyols ~ormed which
i
are capable o~ cyclizing in the presence of a strong~aci~
~u¢h a~, ~or e~ample, the cyclization o~ 1,4-butanediol
(BAD) to tetrahydrofuran (THF). -
Th~ proce~ of this in~ention i~ illu~trated by
the follo~ing reaction ~equence u~ing 2(3'-propanal)-5-
methyl dlo2ane (PND) a~ a representatlve example Or the
- 2 -
'' ~ ,'
.
106672Z
cyclic acetal aldehudes de~cribed herein:
o ~O~CH
I H-C-CH2-CH2-C~ -C~ CH-C ~ + ~ Hydrogenation
\ ~ Catalyst
0~ ~ ~CH
C ~ -C~ -C~ -CH / CH-C~
O,_
OH
II C ~ -C~ -C ~ -C~CH-CH~ Ion E~chan~o Re61n
/ ~ Hydrogenat~on Catalyst~
O--CH
HO-C ~ -CH-C ~ -OH + ~O(CH~)40H
. CH3
~~ and, optionally,
` H2f--~ :
III HO(C ~)~oH Ion e~change resi~ ~ C~ ~CH2 + ~ O
.
,~ .
The practlce o~ thi~ i~vention preclude~ the
formatlon of in~oluble blsacetal~ ~hich cause louer yleld~ ~
ln a one-step hydroly~is-hydrogenation reaction. In a
one-~tep reactlon, bisacetal Pormation eompete~ Nith the
.~' hydrog~nation oP ~ree aldehyde ~hich occur8 too ~lo~ly
to obviat~ the ~ormatlon of th~ bi~acetal. Bl~a~etal~ Porm
by reaction Or free 1,3-diol ~ith the star.tin~ alaehyde- ..
.~ ac~tal as illustrated belo~, again uslng PMD as an ex~mple~
;~ . . .
',''~ '-
-3-
.. ~
.
. .
~0667Z2
C~3
/ CH2 \ / C~ ~H+]
C~ -CH ~ CH-C ~ -C ~ -CHO ~ C ~ ~ H ?
.~ CH2 - 0~ OH ~~~
~ Q~ /o -'C}~
3-CH / CH-CH2-C~ -CH ~ / CH-C
CH2 0 0--CH2
The bisacet~ls tend to bc insoluble, partieularly at tempera-
ture~ lo~or than th~ir ~ormation tomperature, and, as a re-
sult, they precipitate out durlng operation Or the process.
Particularly in continuo w co~mercial operatlon~, the amount
~ .... ..
Or precipitat0 ~hich settles out a~ter several cycle~ can
be slgni~lcant enough to cause the equipment to bocome
~: plugged, nccos~itating ~hut-do~n, clean-ou~ and a ne~
start-up. It wa8 completely unexpected, howeYer, that
pre-hydrogenation o~ the cyclic acetal-aldehyde could ~olve
; this problem ~thout creating an evon greator di~iculty
since it i8 ~ell kno~n that acetal gro~ps ~orm ether
linkagos on hydrogenation a~ see, Por example, Re~ctions
Hydrogen ~lth Or~anic Compounds over Copper, Chromium
O~ido and Nlc~el Catalyst~ by Homer Adkins, P. 75. Si~ce
the eth~r llnkage i8 stablo to hydrolysi~, it ~ould be
~; expected that prohydrogenatien ~ould dereat the goal Or thl~
~nvention. Contrary to this expectation it ha6 been ~ound
th~t polyol8 can be easily and e~Piciently prepared w~thout
the Pormation oP bisacetals and ~ithout the P~rm~tlon o~ :
ether- by hydrogenation o~ the a~etal-aldehyde be~ore the ~. ;
hydroly~1~-hydrogenatlon reaction.
As u~ed herein, the term polyol i~ intendod to :-~
in¢lude dlol~ a~ weli a8 tri- and higher hydro~y contalning
compound~. -
4 _
, ,, , ," ;~
1oUi~7 Z~Z
The acetal-aldehyde~ which may be prehydrogenated
and hydrolyzed and hydrogenated and, i~ desired, cyclized
in accordance with thi~ invention contain one six-membered
acetal ring as well as o~e aldehyde functional group attached
to the acetal ring directly or, indirectly, through a cyclic
or acyclic, saturated or un~aturated group which i8, in turn,
attached to the acetal ring at the carbon atom which sepa-
rate~ the oxygen atoms in the acetal ring.
The acetal-aldehydes to be proces~ed in accord-
ance with this invention have the general formula:
R
R4
O O
wherein X i~ -CH or -MCH in ~hich M i6 an alkyl g~oup,
preferably having one to twenty carbon atoms, with the
proviso that the -aH group may be attached to any M carbon
atom having a replaceable hydrogen; and R~ , R4, R5
and R6 may be the same or different and may be hydrogen or
an alkyl group, preferably having one to 20 carbon atom~.
Although alkyl group~ ha~ing mors than 20 carbon
atoms can also be u~ed as M and Rl, R2, ~ , R49 R5 and ~6~
20 the upper limit of 20 carbon atom~ iB preferred to preclude - -
too high a molecular weight. The alkyl group8 may also con-
tain any ~ub~tituent~ which will not interfere with the
hydrolysi~-hydrogenation reaction of the invention.
. .
10667Z2
Some specif~c examples o~ acetal-aldehydes which
may be hydrolyzed and hydrogenated in accordance ~ith
thiæ invention ~nclude
( Cl-C20)
~Q~
CH(Cl-C20)c~O
O ,
~0,~
~ ~CH-CH2-C~I2-CHO
o
CH a~
CH3
\C~I-CH2-CH2-CHO
., .
' 0~
(CH3)2 ~ CH-CH2-C ~ -CHO
, 0~ ~C~O ''"',
;`` ~ ~ 3 ::
.. ~ .
``.`~ o~ C~O .
3 ~ CH-CH-C~
. ' '
`~ ~ ~ CHO
~ /CH-CH-C~
O
o CHO
( CH3) 2~ ~CH-CH-CH3
J
;
~ ' , . . .
10667ZZ
In the prehydrogenatlon reaction, any catalytic
amount of any of the metal or metal compound catalysts Or
the type well known and customarily re~erred to in the
art as hydrogenation catalysts can be used. It i8 desirable
to employ as the hydrogenation catalyst a metal or 8
compound Or a metal which may be easily and economically
prepared, ~hich ha~ a high degree of activ~ty, and which
retains its activity under the conditions o~ the process for
a length o~ time sufricient to avoid the neces~ity Or re-
activating or replacing the cataly~t at too fr~quentintervals. Generally spesking, hydrogenation catalysts
uh~ch may be employed in th~ e~ecution of the process of
the invention lnclude the metal hydrogenation catalysts,
such as platinum, palladium, gold, silver, copper, v~nadium,
~ tungstcn, cobalt, nickel, ruthenium, rhodium, maneanese,~;
; chromium, m~lybdenum, iridium, titanium, zirconium, and the
like and mixtures Or the same and compound~ and alloy~
thereof, particularly o~ides and sulrideæ thereo~, and like --
hydrogenation cstalysts. Because o~ the easc and economy
Nith ~hich they m~y be preparod, the base metal hydrogenation
catalysts, p~rticularly the pyrophoric base metal hydrogena-
tion catalysts such as nickel, cobalt, and iron, are
advantageou~. Mo8t important are nickel aluminu~ alloys
~hich are activated by partial removal o~ the alumlnum
~ith NaOH. The hydrogenation ¢atalyst mu~be employed
in a ~inely dividod ~orm and di~per~ed in and throughout
the reaction mlxture, or it may be employed in a more ma~sive
state, either in e8~entially the pure state or supported
upon or carried by an inert or catalytically active
~upporting or carrier material, such a8 pumice, kieselguhr,
dlatomaceous earth, clay, alumina, chaxcoal, carbon, or
the like, and the reaction mixture contacted therewith a~ by
, . .
.
-
- 10667Z2
~lowing the mixture over or through a bed o~ the cataly8t
or according to other methods that are known in the art.
me prehydrogenation ~s carried out at an
elevated temperature under ~uperatmospheric hydrogen
pressure. If desired, the prehydrogenation reaction can
be carried out in an aqueous medium in which ca~e the
uater act~ as a heat sink and a viscosity ad~ustor although
the reaction can alæo be carried out neat, that is,
without the use of water. If an aqueous medium i8 used,
it is convenient to have enough water present ~or the
hydrolysis-hydrogenation step; that i8, a molar ratio o~ -
water to acetal-aldehyde o~ 100:1, pre~erably
10:1. A hydrogen pres~ure o~ 50Q - 10 000 psig,
preferably 1 000 - 5 000 psig and a temperature o~ 40 -
150 C. are generally used for the pxehydrogenation
reaction.
The acetal-alcohol thus formed i8 then hydrolyzed
and hydrogenated in an aqueou~ medium. If water i~ not -
used in the prehydrogenation step, it iB now added to the
` 20 acetal-alcohol at a molar ratio of water to acetal-alcohol
of 1:1 - 100:1, pre~erably 1:1 - 10:1. A hydrogen pressure
~ o~ 500 - 10 000 psig, pre~erably 1 000 - 5 000 psig and
- a temperature of 65 - 150C. are employed.
The hydrogenation catalyts disclosed a~ use~ul in -
the prehydrogenation step may also be used in the bYdrolysi~-
hydrogenation reaction. Any strongly acidic water insoluble
ion e~change resin may be used in the hydrolysis-hydrogenation
reaction. Typical resin~ are tho~e containing sulfonic acid
groups such as those di~closed in ~.S. Patent 2 366 007 i~ued
A, 30 December 26, 1944 to G.F. D'Alelio which include sulfonated
styrene-divinyl benzene copolymers commercially available as
"Dowexn* MSC-l, 50 and 50 WX8; "Amberlystn* 15 and the like
* denote~ trade mark
--8--
10667ZZ
resin~. Other ~ultable cation exchange resins include,
for e~ample, the phenol sul~onic acid-~ormaldehyde
reaction products.
The insoluble resin and the hydrogenation
cataly~t Nhich form the catalyst system o~ thi~ invention
may ~ist in variou~ interrelationships with one another
as de~ired but typically a ~elght ratio Or insoluble resin
to hydrogenation catalyst o~ 0.1:1 to 100:1, prererably
1:1 to 10:1 iB uBed.
Dependln~ on the product desired and the kind
o~ reaction system employed (slurry, ~ixed b2d and 80 on),
any hydrolytic-catalytic amount Or the catalyst sy~tem
o~ thls invention may be employed. ~enerally, amounts o~
the acid-cataly8t ~ystem are employed such that 1% by
welght o~ hydrogenation catslyst baBed on the Nelght of the
scetal-alcohol i8 pre~ent. In a slurry system 1-10% by
~eight based on the content~ o~ the reactor are optimum
and in a ~ixed b~d reactor, 10 to 20 times as much may be
~ u~ed.
-- 20 The reaction o~ thl~ invention may be carried
~` out ~ither continuou~ly or batchwi~. In either ca~e,
the time during ~hich the reactor contents are in ¢onta¢t
~ith the cataly~t systo~ depends on the product de~ired,
` By manipulating temperature and contact time, one may
produ¢e either polyol product or the cyclized rorm or ~ny
polyol whi¢h i8 capablo o~ being cyclized in a ~trongly
acid medlum or any combination thereo~. As temperature
and contact time increa~e, the cyclization reaction i~ ;
ra~or-d. Taking BAD as an example, greater than 90% yields
30 Or cycli~ed 9AD (1~) can be obtained at higher tempera- ~ ;
ture~ and contact times while 99% yield~ Or BAD c~n be
9 ~ :-
~ 6 ~Z ~
obtained at lower temperatures and contact times. Any
interrelationship between temperature and contact time o~
up to 3 hours at 60C. and up to one hal~ hour at 150C.
can be ob~erved. At 130C. or higher, THF ~orm~ very
rapidly and pre~erentially. Other methods ~or producing
1~ uslng cation exchange resins are disclo~ed in U.S.
Patent 3,467,679 i~ued September 16, 1969 to A.O. Rogers
and aerman Patent 850,750 issued September 29, 1952
to I.a. Faxbenindustrie.
The polyols produced by the process o~ this
in~ention may be used ~or any application Por which polyol~
are suitable such as reactant~ ~ith isocyanates to form
urethanes and polyurethanes, with acids to form esters and
polyesters and 80 on.
The invention is further illustrated but i~ not
intended to be limited by the ~ollowing examples in which
all parts and percentage~ are by weight unless otherwi~e
speci~ied.
,.... EXA~E 1 '~
A 40 g. mi~ture o~ the monocyclic acetals, 2-(3~
propanal)-5,5-dimethyl-1,3-dioxane (90 and 2-(2~-propanal)-
5,5-dimethy1-1,3-dloxane (100 is hydrogenated at 60C.,
`;~ using 5 g. of Raney nickel and 2500 p8ig of hydrogen. The
.,
reaction time i~ 50 minutes and the reactant ald~hydes are
completely converted to their cQrresponding alcohols, i.e.,
, the monocyclic acetal~ 2-(3'-propanol)-5,5-dimethyl-1,3-
dioxane and 2-(2~-propanol)-5,5-dimethyl-1,3-dioxane.
. j ~.
., .
. .~
--10 -
- , . .: . . . - , - ~
10667ZZ
H~drolysis/kydrogenation
The mixture o~ the cyclic acetals prepared
above is reacted with 20 g. o~ water in the presence of
five grams o~ 30 mesh cross-linked sulfonated polystyrene
("Dowex" -50) and 5 g. of Raney nickel at 85C.. and hydro-
gena~ed with 1 000 psig o~ hydrogen for one hour. Gas
chromatographic analysls indicates that the linear isomer
undergoes 86% conversion to yield 0.4 mole percent tetra-
hydro~uran and 99.6 mole percent 1,4-butanedlol. me
branched isomer undergoes only 42% conver~ion.
In an identical reaction except that the tempera-
ture is 130C., the linear isomer undergoe~ 99.2% conver-
sion and yields 52 mole percent tetrahydrofuran and 48
mole percent 1,4-butanediol.
The prehydrogenation and hydrolysis-hydrogenation
procedure de~cribed in Example 1 is repeated except that
a 40 gram mixture o~ the acetal-aldehydes describèd in the
following table are used.
`~ ' ... .'
... . .
. ~
.,~
.
r`
~,: ', ' '
~1 .
.`' ',; ''
-11- .
'i . - : :'
., ~ ~ - .
~06~;7ZZ
~o
~ , ~
.~ ~ ~: o~
' m ~ a~ .
~ ~1 ~D 0. U~
E~ O ~ o
o I
g U~
`-1 H
CO ~D 1`
P ~ co a~
o -,
C~
. . , , ` .
t~ U
U~ o U)
. E~ oo o~ co ",
.. ~
~ I .
. Cq ~ ~ ~ ~
.; ~ I .,, .,1 ~ ,.
_l
'' aJ ~ ~ ~ U~ o
,~ ~ ~
~:` ~ :C
.~ .
.~ O
E~ o ~
, E~
; a~ I
.~ d ~
,~` E~
O o o o
.,~ ~ U~
.. ~ .
. ` ` .
l x l x l x ~ x ~ l
' _ O ~ O ~ O ~ O
~; d ~a -d ~ d 'd ` 'a d ` d `
~, d ') ~J ~ ~ ~ ~ r~ ~ I ~D d ~ 'r
.~ D. ~ Q, ~ ~ ` Q. ` Q
0-~1 0 ~1 0 ~1 0 ~ O :~. O :~
'O ~ I ~ Ih I 1~l 1 ~ S ID 5~ S IU
: ~ ' .C ' .~ X ' ~ x
.i . OQ ~ ~ tP ~ ~ t~ JJ "p ~ ~ ~p ~." o ~ o
U ~ ~ ~I N ~ N ~
,t ~ ~ :
W
.
-- 12 --
106~;7ZZ
EXAMPIE 5
A hundred grams of 2-(3t-propanal)-5,5-dimethyl-
1,3-dioxane 84~ and 2-(2'-propanal)-5,5-dimethyl-1,3-
dioxane 16% are treated with hydrogen at 1 000 p8ig
hydrogen presæure in the presence of 5 g. of Raney nickel
at 80C. The reaction i8 co~plete in 60 minute~. The
reaction product i8 then ~iltered and reacted with 50 gram~
Or water and hydrogen at 1 000 psig hydrogen pres~ure in
the presence of 5 grams o~ a cross-linked sul~onated poly-
styrene ("Dowex" 50) and 5 grams o~ Raney nickel, for 2hour~ at 80C. An 80% conversion is obtained and the
yield contains 0.9 mole percent tetrahydr~uran and 98
; mole percent of 1,4-butanediol.
It is to be understood that any Or the compo-
nents and conditions mentioned as suitable herein can be
substituted for its counterpart in the ~oregoing examples
and that although the invention has been described ln
considerable detail in the ~oregoing, such detail is
solely for the purpose of illustration. Variations can
20 be made in the invention by those skilled in the art ~`
without departing from the spirit and scope of the inven-
tion except a~ set forth in the claims.
` ~'.'~
. . .
~; ,
"~' .
'~?, . . ~
', ,.: ., ' '
.,
13-
