Note: Descriptions are shown in the official language in which they were submitted.
1~96134
BACKGROUND AND SUMMARY OF THE INVENTION
The method of producing 1,4-butynediol by the
reaction of formaldehyde and acetylene using a copper
acetylide complex as a catalyst is, of course, well known
and has been used for many years. It is also well known
that this reaction produces cuprene, which tends to clog
filters and affects the process adversely.
one method commonly used to inhibit cuprene forma-
tion during the reaction is to conduct it in the presence of
bismuth, either in elemental form or in the form of a bis-
muth compound. In Kirchner U.S. Patent 3,650,985, for
example, it is demonstrated in Example 39 that bismuth
oxycarbonate can be used as a cuprene inhibitor by mixing
it, in the initial stage of the process, directly with the
basic copper carbonate (malachite) used to form the copper
acetylide catalyst. While bismuth used in this way does
inhibit cuprene formation, it tends to separate from the
catalyst after a time, which leads to unsatisfactory
results.
One method of dealing with the separation of bis-
muth from the catalyst is shown in Belgian Patent 825,446,
according to which bismuth is uniformly dispersed in a
malachite precursor, and subsequently in the copper acety-
lide catalyst itself, by first preparing hydrated copper
carbonate particles, nucleating and converting these
particles to malachite by heating them, and then growing
agglomerates of malachite containing bismuth oxycarbonate
uniformly dispersed therein by adding solutions of a copper
salt, a bismuth salt and an alkali metal carbonate to a
water slurry of the malachite. This malachite is easily
converted to a copper acetylide catalyst.
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While the bismuth compound in a catalyst thus pro-
duced tends to stay in place, the catalyst is composed of ag-
glomerates of angular crystals which are degraded by attrition
: as the butynediol reaction proceeds, which interferes with its
efficiency.
This problem, as well as the others just mentioned,
is minimized by the use of the malachite and copper acetylide
catalyst produced according to this invention, whose agglome-
~ rates are spheroidal and contain uniformly dispersed bismuth
;.' 10 oxycarbonate.
The spheroidal agglomerates of malachite can be made
.~ according to the invention by first forming a mass of hydrated
copper carbonate by bringing together, with mixing, an aqueous
.~
solution of a cupric salt, an aqueous solution of a bismuth
salt and an aqueous solution of an alkali metal carbonate or
bicarbonate. This mixture is then held, without stirring or
agitation, at a temperature of less than about 55C, whereupon
the spheroidal agglomerates of malachite crystals form.
These agglomerates can, in turn, be converted to
copper acetylide complex by slurrying them in water and then
subjecting them to the action of acetylene and formaldehyde.
DETAILED DESCRIPTION OF THE INVENTION
The process of the present invention consists essen-
tially of:
(A) forming amorphous gel-like hydrated copper
carbonate by bringing together with mixing,
at a temperature less than about 55C,
enough of
(1) an aqueous solution of a cupric salt,
(2) an aqueous solution of a bismuth salt,
and
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613~1L
(3) an aqueous solution of an alkali
metal carbonate or an alkali metal
bicarbonate, to yield a mixture with
a pH value of 5.5 to 7.5;
and then
(B) holding the mixture of (A), without agitation,
at a temperature less than about 55C.
Any water soluble cupric salt can be used in the pro-
cess of the invention. Illustrative are cupric nitrate, cupric
chloride and cupric sulfate. Cupric nitrate is preferred
because of its solubility and availability.
Similarly, any water soluble bismuth salt can beused. -
Illustrative are the nitrate, the oxycarbonate, the citrate,
the sulfate and the phosphate. Bismuth nitrate is preferred,
also because of its solubility and availability.
Of the alkali metal carbonates and bicarbonates which
can be used, sodium carbonate and sodium bicarbonate are pre-
ferred becuase of their low cost.
Each salt solution is prepared so that it contains as
` 20 much salt as possible without it crystallizing from solution on
,. .
standing or during use. The solutions are then brought to-
gether in such proprotions that the pH of the resulting mixture
`;is about 5.5 to 7.5, preerably 6.0 to 7Ø In the usual case,
this pH range can be attained by the use of an appropriate
amount of the alkali metal carbonate or bicarbonate solution.
The bismuth salt is usually present in the resulting mixture at
a concentration of 1 to 10% by weight, of the copper content.
The solutions can be brought together in any order,
generally over a period of 20 to 60 minutes, and are then mixed
by stirring or by agitation. In a preferred embodiment, a
solution of the copper salt and the bismuth salt is prepared,
and this is fed to a small heel of water, simultaneously with a
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solution of the alkali metal carbonate or bicarbonate, as
shown in Example 1.
It is improtant that the solutions be brought to-
gether in a vessel which has been cleansed of malachite
nuclei by first rinsing it with dilute nitric acid.
The resulting mixture is held at a temperature of
just slightly about the freezing point of the medium to about
55C, preferably 35 to 50C, with stirring or agitation. An
amorphous mass of gel-like hydrated copper carbonate forms
immediately.
The agglomerates of malachite are then prepared from
the hydrated copper carbonate by holding the liquid in which
the carbonate is contained at about the same temperature as is
used in the gel-formation step, without stirring or agitation
of any kind. Carbon dioxide begins to evolve and agglomerates
of malachite crystals form.
The malachite thus formed consists of spheroidal ag-
glomerates of basic copper carbonate crystals. At least about
80% of these agglomerates are about 5 to 12 microns in the
longest dimension, as determined optically against a standard.
The agglomerates contain 1 to 4%, by weight, of uniformly dis-
persed bismuth oxycarbonate, preferably 2 to 3%. "Uniformly
dispersed" means the oxycarbonate is evenly distributed
through all of the agglomerate on a molecular scale.
The agglomerates then separated from the reaction
mass by filtration, and washed free of salts with water. When
higher concentrations of bismuth salt are used in preparing
the agglomerates, it is desirable that residual gel and
smaller agglomerates be removed by hydrocloning the reaction
mixture before the filtration step. A suitable apparatus for
this step is the Dorr Clone*, made by Dorr-Oliver, Inc., of
Stamford, Connecticut.
* denotes trade mark
~ 9~.34
These malachite agglomerates can be converted into
copper acetylide catalyst by preparing a slurry of agglome-
rates in water and then subjecting this slurry to the action
of acetylene and formaldehyde. This procedure is described in
more detail in Kirchner, U.S. Patent 3,650,985, beginning in
column 5.
The copper acetylide complex produced in this way is
in the form of spheoidal agglomerates containing uniformly
dispersed bismuth oxycarbonate, at concentrations which paral-
lel that of the malachite from which the complex is prepared.
The complex can be used as a catalyst for the re-
action of acetylene and formaldehyde to produce 1,4-butynediol.
The complex is used in the customary way and in the usual
amounts, and no special techniques or precautions are necessary.
Details for such use can be found in Kirchner U.S. Patent
3,650,985.
EXAMPLES
Example 1
In 100 ml of water were dissolved
( 3)2 2 g
Concentrated HNO3 10 ml
( 3)3 2 1.74 g
The resulting solution was fed, with stirring, over
a 40 minute period, to 300 ml of water held at 35C. Enough
saturated a~ueous solution of Na2CO3 was added to keep the pH
of the solution at 6.7 to 7.2.
Stirring was then stopped and the solution held at
35C. A blue gel filled the vessel; this gel contracted
to 1/8 its original volume in about 2-1/2 hours to form
spherical agglomerates of malachite crystals, which were
1~9G'~ 3~
then separated from the liquid by filtration, washed with
water and then dried at 100C for 1 hour. This product was
then hydrocloned to remove residual gel and small particles.
At least 80~ of these agglomerates were 5 to 12
microns in the longest dimension.
Example 2
To a glass vessel were charged
Malachite of Example 1 45 g
Formaldehyde (37~ in 600 g
; 10 water)
CaCO3 2 g
A stream of acetylene containing 90% by volume of nitrogen
was passed through the vessel at a rate of 2 liters/minute.
The pressure within the vessel was held at 4 to 5 psig and
the temperature of the reaction mass at 70 to 80C. The
carbon dioxide which formed was vented to the outside.
When carbon dioxide evolution stopped, the con-
tents of the vessel were cooled, removed from the vessel
and washed with water.
The resulting copper acetylide complex was stored
under water until ready for use.
Example 3
To a reactor vessel were charged
Copper-acetylide complex 45 g
of Example 2
Formaldehyde (15% in 600 ml
water)
Acetylene was continuously passed through the vessel at a
rate of 300 ml/minute, the pressure being maintained at
about 5 psig. Enough of a 37% aqueous solution of formaldehyde
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1ai96134
was continuously fed into the vessel to maintain a formalde-
hyde concentration of about 10% by weight. Similarly,
enough of a saturated solution of sodium bicarbonate was
continuously fed into the vessel to hold the pH of the con-
tents at 6.0 to 6.2. The product, 1,4-butynediol, was con-
tinuously removed by filtration.
After lO0 hours of continuous use, the catalyst
was removed from the vessel and analyzed by X-ray diffraction
scanning. No metallic copper was detected, indicating that
the catalyst remained stable and useful.
Example 4
The process of Example 1 was repeated, using 5.8 g
of bismuth nitrate instead of 1.74 g.
The resultingspheroidal agglomerates of malachite
contained 4%, by weight, of uniformly dispersed bismuth
~: oxycarbonate.
These agglomerates can be converted to copper
acetylide catalyst as shown in Example 2, whi~h in turn can
:; be used in the procedure shown in Example 3 to form
1,4-butynediol.
