JPS594380B2 - Method for producing crystalline particle agglomerates of basic copper carbonate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for co-precipitating malachite with bismuth to produce a crystalline particle agglomerate of basic copper carbonate.

In the formation of 1,4-butynediol by the reaction of acetylene with formaldehyde in the presence of a copper acetylide complex catalyst, it is desirable to prevent the formation of cuprene, or polymerized 10-acetylene, by the use of an inhibitor such as bismuth oxide. Are known.

Retzpe et al. (1942) in U.S. Pat. No. 2,300,969 describe the use of several such inhibitors when producing and using such catalysts at elevated pressures, such as about 20 atmospheres. is discussed. U.S. Pat. No. 3,650,985 describes the utility of bismuth oxide as a cuprene inhibitor in the production and use of copper acetylide catalysts at low partial pressures of acetylene (less than 2 atmospheres). None of these 20 prior art patents show anything about how the bismuth component is uniformly contained in the catalyst itself. US Patent No. 3
, 650, 985, if bismuth oxide carbonate is added separately to the previously formed malachite, unsatisfactory results are obtained as it separates in the final catalyst formed. It was found that it brings about

It would therefore be desirable to have a satisfactory process for co-precipitating bismuth in the catalyst precursor basic copper carbonate or malachite. The basic copper carbonate CU2(OH)2CO3, known as malachite, is commonly produced by one of two precipitation methods.

The first method is to prepare a solution of a copper salt, such as copper nitrate or copper chloride, with atrium or potassium carbonate or bicarbonate.
This is a method to neutralize the amount to 7.0. Initially hydrated copper carbonate, or amorphous CU0C3.X(H2O), precipitates in the form of a viscous gelatinous material, which upon heating CO
is eliminated and gradually converted to malachite. Malachite crystal precipitates prepared by this technique generally consist of irregularly shaped particles with average particle cross-sectional dimensions ranging from less than 1 micron to more than 25 microns. If the gel had been sufficiently set, the irregularity in crystallite size and its wide distribution during crystallization would be the result of its destruction as the gel precipitated. The irregularly shaped crystallites and wide distribution of particle sizes are rather undesirable for use as a precursor in the production of the ethynylation catalyst cuprous acetylide. Another method to precipitate malachite is to add the copper solution described above and the carbonate neutralizer described above simultaneously with stirring so as to maintain ... in the range of 5 to 8. The hydrated copper carbonate thus obtained is then also converted to malachite at ambient temperature, but more rapidly as the temperature increases. This procedure produces a more regular crystalline product consisting of agglomerates of individual crystallites with cross-sectional dimensions averaging about 2-3 microns. These agglomerates range in size up to about 30 microns. As with the first method of adding the carbonate neutralizers to the copper solution, this method of adding them simultaneously also initially forms amorphous hydrated copper carbonate. It would be desirable to have a method for producing basic copper carbonate crystalline particles that are bismuth loaded and yet fairly uniform and of relatively large particle size.

Uniform dispersion of bismuth within the particles is desirable for forming the ethynylation catalyst, in which case the bismuth component remains therein and remains effective in inhibiting taperene formation. In certain embodiments, the present invention provides a method for making crystalline particles of basic copper carbonate having bismuth uniformly dispersed in an amount ranging from 1 to 5 wt.e. based on the amount of copper present. It is something to do.

The method consists of three steps. It is sometimes preferred to first precipitate the hydrated copper carbonate particles by simultaneously adding a solution of the cupric salt and a solution of the alkali metal carbonate or bicarbonate to water to form a reaction mixture. The solutions are proportioned to maintain the pH in the range of about 5.0 to 8.0. The hydrated copper carbonate is then converted to basic copper carbonate in the reaction mixture at a temperature of at least about 60°C. This transformation occurs through the nucleation of malachite crystallites from amorphous hydrated copper carbonate. The next addition of copper, bimasma and carbonate precipitates more malachite on these transformed nuclei. Nucleated crystalline particles and agglomerates of such particles grow with bismuth uniformly incorporated into the particles. The reaction mixture is maintained at a temperature of at least about 60° C. during growth. cupric salt, bismuth salt and sodium carbonate or Add each solution of sodium bicarbonate. Bismuth content is herein expressed in weight percent based on the amount of copper present.

Parts, percentages and proportions herein are by weight unless otherwise indicated. Although it is necessary to have bismuth present during grain growth, it is desirable, and often in practice necessary, to also have it present during the precipitation and nucleation stages.

Co-precipitated basic copper bismuth carbonate particles can be used to prepare cuprous acetylide complexes useful as ethynylation catalysts and are described for reference.

The particles of basic copper-bismuth carbonate are treated as a slurry in an aqueous medium at 5σ to 120° C. with formaldehyde and acetylene at a partial pressure of not more than 2 atmospheres. Its aqueous medium is 3-100P at the beginning of action.
It has H. Preferably, the reaction is continued until all of the copper precursor has been converted to cuprous acetylide complex. For the medium in which this action is performed, it is desirable that ... be in the range of 5 to 8, at least initially.
The catalyst produced essentially has the general formula (CuC2)w(CH2O)x(C2H2)y(H2O
)z-Bi (where w=4, x=0.24-4.0
, y=0.24-2,40 and z=0.67-2.8
0 and bismuth is present in an amount of 1 to 5%).

The complex particles are at least 5d/G. and the average particle cross-sectional size is at least 10 microns.
Preferably the particulate complex has a size of 15 to 75 m2. with a total area of , average particle cross-sectional dimensions ranging from 10 to 40μ, 20 to 66% copper, 2 to 12,5 carbon atoms per copper atom, 0.2 to 2 carbon atoms per carbon atom. hydrogen atom,
0.1 to 1 oxygen atom and 2 to 47 per carbon atom
Contains 0 bismuth.

Compared to conventional methods for producing basic copper carbonate crystals, the method of the present invention involves rapid precipitation of hydrated copper carbonate, subsequent nucleation and formation of basic copper carbonate ( malachite). The nucleation and transformation is facilitated by elevated temperatures, for example above 60°C. A larger portion of the reaction components to produce basic copper carbonate, such as at least two-thirds of the copper, is not added to the reaction mixture until after conversion to basic copper carbonate. At this point, the copper salt, neutralizing agent, and bismuth readily combine to produce a uniform dispersion of bismuth into the basic copper carbonate crystalline particles of fairly uniform and large particle size. This crystal growth inhibits the initial formation of gelatinous hydrated copper carbonate. The complete production of basic copper carbonate crystals, including the formation of precipitates, nucleation and growth, occurs at elevated temperatures, e.g.
If carried out above 0.degree. C., the hydrated copper carbonate will not exist for long periods of time.

Nucleation and transformation occur rapidly and are the main phenomena with initial nuclear growth occurring. Operating all stages of production at elevated temperatures therefore leads to the production of fewer, larger particles. In practice, each step will occur at lower temperatures, such as room temperature (about 23°C). Before crystal growth reduces the concentration of the reactants, a large number of nuclei form and convert to malachite, resulting in an increase in particles of smaller size. Also, in the process of producing malachite at lower temperatures, the bismuth component is not uniformly contained in the basic copper carbonate produced in this process, but is used as an ethynylation catalyst during or after the formation of the carbonate. The cuprous acetylide complex tends to separate during either use of its carbonate to produce the cuprous acetylide complex. It is therefore important to use the process of the present invention to produce basic copper carbonate-bismuth coprecipitates to be used in preparing ethynylation catalysts. To produce crystallites and agglomerates of smaller size, nucleation is performed at lower temperatures and then the temperature is increased to 6.
Elevation above 0° C. allows relatively rapid conversion and growth and uniform dispersion of bismuth.

To produce larger size crystallites and agglomerates, nucleation is also carried out at higher temperatures, such as above 60°C. If the PH increases by at least 1.0 units between the nucleation and growth stages, greater uniformity in particle size can be provided. Crystal growth occurs best in the zone of the solubility-temperature curve that represents supersaturation. The supersaturation zone is wide for these products at higher pH values. Higher pH within a limited range will therefore lead to more deposition on existing nuclei and will result in less generation of new micronuclei if the reaction continues to be carried out in the supersaturated zone. . The conversion of hydrated copper carbonate to malachite can be easily observed as malachite nucleates.

Hydrated copper carbonate is blue in color and tends to form a structureless gelatinous mixture. Malachite is green and crystalline. When sodium carbonate is added to a copper nitrate solution with a pH of 3, the reaction product forms as a thick gel as the pH increases to 41.

Subsequent lifting and agitation breaks down the gel into malachite, producing highly irregular particles related to the size of the broken gel. Above a pH of about 8.0 and at elevated temperatures, amorphous copper carbonate hydrate begins to convert to undesirable copper oxide. If ... is less than 5.0, gel formation becomes difficult. Note that sodium iodide can be added separately during the production of the catalyst.

This produces some bismuth oxyiodide in the catalyst, which acts as another inhibitor to cuberene formation. The catalyst has an agglomerate size of about 15-20
It is desirable that it be μ. Larger particles are advantageous over smaller particles because they are filtered and dried more quickly and dust formation and banding do not occur during settling. 5
An agglomerate size of 0μ is too large than desired because the activity of the catalyst is reduced.

Catalyst particles that are too small make filtration difficult. The size of the agglomerates can be easily controlled by adjusting the temperature and pH during the basic copper carbonate production step. During the ethynylation reaction, acetylene prevents the valence change of cuprous to elemental copper or cupric in the catalyst.

This is desirable because elemental copper is the catalyst for polymerizing acetylene to cuprene. Cuprene is highly undesirable in these reactions because it tends to block the strainer and cannot be easily removed. Under certain conditions in manufacturing operations, the flow of acetylene to the reactor is shut off due to an emergency or sudden loss of supply. Bismuth, which is uniformly contained in the catalyst in the form of oxidized carbonates, helps protect the catalyst from such decomposition at heat and even in the absence of acetylene. Above 4 or 5% bismuth, the second phase tends to separate from the catalyst after several weeks of operation in the ethynylation catalyst.

This is evidenced in the production of particulates which themselves make filtration difficult. Such separation also tends to deactivate the bismuth in the catalyst. At solubility levels of about 0.5 pIn in the ethynylation reaction medium, bismuth is leached out of the catalyst.

This is a problem when the bismuth content of the catalyst is above about 3%, but is not a significant problem until the bismuth content is above about 5%. In a preferred procedure according to the invention, bismuth nitrate is dissolved in a copper nitrate solution at the desired concentration and then added simultaneously to the crystallization vessel along with the sodium carbonate.

While the crystals are growing, the temperature is maintained at 6 to 7 and the temperature is in the range of 60 to 80°C. To obtain larger crystals, the temperature is also initially in the range for precipitation and nucleation. Bismuth is effectively coprecipitated and uniformly distributed in the resulting malachite. When such bismuth-containing malachite is utilized to produce cuprous acetylide complexes, which are ethynylation catalysts for butyne diol synthesis, substantial improvements in catalyst permeability and stability result. It will be done. Bismuth-containing malachite was produced using the initial nucleation method according to the present invention, and was produced at 1%, 270, and 3%.
%, 4%, 8%, 10% and 15% bismuth concentrations.

The resulting malachite is then used to produce an ethynylation catalyst. In order to demonstrate the superior properties of the malite obtained by the process of the invention, it will be shown that the catalyst thus obtained has an improved stability and performance, as shown by the absence of cuprene formation. They are subjected to long-term life tests to determine the
For comparative purposes, a catalyst is similarly prepared using commercially available malachite. The life test is conducted for about 100 hours or more, at which point the catalyst is removed and tested for the presence of cuprene. Taprene is easily detected by its copper color, which floats on the surface of the formaldehyde-in-water solution commonly used to make butynediol. Excess bismuth salt can also be eluted from the catalyst and form other colored residues. Life test results show that catalysts made from bismuth-free malachite precursors produce substantial amounts of cuprene during a 100 hour life test.

Analogous to the sudden disappearance of acetylene in a butynediol production operation, if the catalyst is kept hot in the absence of acetylene, even more cuprene is produced. If an additional 5% of bismuth in the form of bismuth subcarbonate is mixed with bismuth-free malachite and the mixture is then converted into a catalyst, substantial cuprene formation is still evident when the catalyst is evaluated. Traces of cuprene are also observed with catalysts containing 1% bismuth, whereas catalysts made from malachite co-precipitated with higher amounts of bismuth remain cuprene-free.

Catalysts produced with 2% or more bismuth co-precipitated in malachite can be used in an acetylene-free environment without deterioration causing excessive cuprene formation, which is considered to have reached the end of the useful life of the catalyst. If the temperature is increased for a short period of time (e.g. up to about 7% of the time), e.g.
It can be maintained at 0 to 95°C. Additions of bismuth of 5% and above result in some amount of bismuth separating from the catalyst after long periods of use.

Bismuth concentrations above 3 or 4% therefore appear to be less desirable, and concentrations in the range of 2 to 4% appear to be optimal for overall operation. One preferred catalyst with a bismuth content of 3% was used for 20 days in the production of butyne diol without any evidence of degradation or cuprene formation. Moreover, the relatively large and uniform particle size catalyst obtained by the present invention can be filtered more easily. In butyne diol production processes where the catalyst system acts as a slurry and the product is removed by a candle filter, larger particle size can increase the filtration rate. Example 1 Malachite-470B1 (cold start) Crystalline particulate synthetic malachite containing 470 bismuth is produced according to the present invention as follows.

Two liquid streams are added simultaneously to a reaction vessel containing 300 cc of water. One stream is a saturated aqueous solution of Na2cO3 and the other is a saturated aqueous solution of CU(NO3)2.3H201009-,
Bi(NO3)3・5H202.329, HN0310
It is an aqueous solution containing cC and H2O9OCC. If these liquid streams are added at such a rate that the pH in the precipitation vessel is continuously maintained at about 6.5, and heat is gradually added from the beginning, precipitation begins. The table below shows the rate of addition of the solution, measured in terms of the copper nitrate solution still to be added, the time from the start of the addition and the temperature of the reaction mixture. PH8
．． The reaction product is aged until F is reached, then F
Strain and dry.

The particles have an average cross-sectional size of 15-20 microns. The product contains 4% bismuth homogeneously dispersed in crystalline particles. Add only about 1/4 to 1/3 of the reactants until nucleation and transformation (although they may occur simultaneously) and then add the remaining reactants after nucleation to contain the bismuth. It is preferable to grow malachite crystals.

Example 2 Malachite - 3% B1 (cold start) Crystalline particulate synthetic malachite containing 3% bismuth is produced according to Example 1, except that Bi(NO3)
Use 3.5H201.749.

The following table shows data similar to that of Example 1 and also gives the indicated PH several times during the reaction.
Nucleation is achieved at a pH of 6.5, and then the pH is raised to 7.5 to grow crystals.

Crystallization is terminated at pH 6.8 to make all malachite insoluble. Next, the product was adjusted to pH 8. Aged at O, washed, filtered and dried. The resulting product has cross-sectional dimensions of 15-25 microns and 3
It has well-dispersed bismuth-containing particles at the Z0 level. Reference Example Catalyst Production In typical catalyst production, 3? Malachite 459 containing bismuth and Cu 2.59 are placed in a glass reactor with a jacket heater along with 37% formaldehyde 6009 and CaCO 329 to neutralize the formic acid formed.

A stream of C2H2 diluted with N2 is passed through the vessel using a sintered glass frit to distribute the gas. Control the temperature between 70 and 80℃ and the pressure 4-5p
control to sig. CO2 is desorbed as malachite is converted to copper acetylide, so the system is equipped with an exhaust port to remove CO2. The system is also equipped with a small gas recirculation pump to recirculate unreacted C2H2, and a surge of C2H2 and N2 is added to maintain pressure. The concentration of 0C2H2 in the exhaust gas as measured by gas chromatography is
It is generally kept in the range of 2-5% by volume to obtain the most active catalyst. After removing all the CO2, the reactor is cooled, the contents removed and the catalyst washed with water to remove the product butynediol and unreacted formaldehyde. The catalyst thus obtained is stored in water until evaluated for stability and long-term activity. Evaluation of Catalyst (Life Test) For evaluation, the catalyst derived from malachite charge 45θ is placed in a jacketed container containing 600 cc of 15% formaldehyde solution.

Acetylene gas is passed through a sintered glass frit to achieve the necessary distribution and mass transfer. The reactor temperature is increased to 90°C and after 8 hours to 95°C. At the same time as the 37% formaldehyde solution is supplied, acetylene is continuously supplied so as to maintain the formaldehyde concentration at a steady state of 10%. The catalyst remains in the reactor as the product is continuously recovered through a sintered glass filter. A solution of sodium bicarbonate is added continuously to maintain the PH in the reactor between 6.0 and 6.2 as determined by PH test. Total reactor pressure. is maintained at 5ps1g. The activity is (02H2 consumed
(weight units of copper in the reactor)/time/(weight units of copper in the reactor) and is calculated continuously from the consumption rate of formaldehyde. Life tests are conducted for approximately 100 hours or more, after which the system is cooled, the catalyst is recovered, filtered and washed to remove reactants and products, and tested for cuprene content. Cuprene is easily detected by its distinctive copper color and tends to float on the surface of the water layer, below which the catalyst being evaluated is stored. The table below summarizes the results of a life test conducted using the cuprous acetylide catalyst obtained as described above.

If more than 5% bismuth is used, various colored substances will be deposited on the catalyst.

Bismuth salts separate as a result of leaching of bismuth from the catalyst. Cuprene is not detected when bismuth is 1% or more. However, cases in which bismuth is not co-precipitated with malachite (tests 11 and 12) are excluded. 2%, 5
Catalysts containing % and 15% bismuth can be exposed to elevated temperatures in the absence of acetylene without subsequent formation of harmful cuprene.

The novel technical matters disclosed by the present invention will be summarized below.

1. The following steps are taken: a solution of a cupric salt and a solution of an alkali metal carbonate or bicarbonate are simultaneously prepared and the solutions are brought to a pH of about 5.
．． The particles of hydrated copper carbonate are precipitated by addition to water to form a reaction mixture in proportions such that at least about 6.
The hydrated copper carbonate is nucleated and converted to basic copper carbonate at a temperature of 0°C, and the reaction mixture contains a cupric salt,
A solution of bismuth salt and alkali metal carbonate or bicarbonate is added to the P of the reaction mixture at a temperature of at least about 60°C.
The basic copper carbonate containing bismuth is precipitated by adding H in a proportion such that it is maintained in the range of about 5.0 to 8.0 and nucleated until the average cross-sectional size of the crystallite agglomerates is at least about 10 microns. 1 to 5 weights based on the amount of copper present, consisting of growing an agglomerate of crystalline particles formed? A method for producing an agglomerate of basic copper carbonate crystalline particles homogeneously dispersed with bismuth in an amount in the range of .

2. 2. The method according to item 1 above, wherein the alkali metal is sodium.

3. 3. The method of claim 2, wherein the cupric salt is copper nitrate and the bismuth salt is bismuth nitrate.

4. The pH of the growth stage is at least 1 greater than the pH of the precipitation stage.
．． 0. The method according to item 1 above.

5. 3. The method of claim 2, wherein the temperature of the growth step is in the range of about 60-70<0>C.

6. 2. The method according to item 2, wherein the pH during the growth stage is in the range of 6.0 to 7.0.

7. 6. The method of claim 5, wherein the pH during the growth stage is about 6.5.

8. Is the bismuth content of the agglomerate between 2 and 4 by weight based on the amount of copper present? The method according to the above item 1, wherein the method is within the range of .

9. 2. The method of claim 1, wherein at least about two-thirds of the copper by weight is added to the reaction mixture during the growth stage.

Claims (1)

[Claims] 1 by adding a solution of a cupric salt and a solution of an alkali metal carbonate or bicarbonate to water in proportions such as to maintain the pH in the range of about 5.0 to 8.0 to form a reaction mixture. particles of hydrated copper carbonate are precipitated in the reaction mixture at a temperature of at least about 60° C., nucleation and conversion of the hydrated copper carbonate to basic copper carbonate is then or simultaneously carried out in the reaction mixture. A solution of a cupric salt, a bismuth salt, and an alkali metal carbonate or bicarbonate is added at a temperature of at least about 60°C to bring the pH of the reaction mixture to about 5.
．． Crystal grains nucleated by precipitating basic copper carbonate containing bismuth by adding in proportions such that the crystallite agglomerates have an average cross-sectional size of at least about 10 microns. A process for producing an agglomerate of crystalline particles of basic copper carbonate homogeneously dispersed with bismuth in an amount of 1 to 5% by weight based on the amount of copper present, characterized by growing an agglomerate of .