JPS6113691B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a process for producing 1,4-butynediol, which comprises reacting acetylene and formaldehyde in the presence of a cuprous acetylide complex. 1,4- by reaction of acetylene with formaldehyde in the presence of a copper acetylide complex catalyst.
It is known that in the production of butyne diol it is desirable to inhibit the production of cuprene or polymerized acetylene through the use of inhibitors such as bismuth oxide. Retzpe et al. (1942) in US Pat. No. 2,300,969 discuss the use of several such inhibitors when producing and using such catalysts at elevated pressures, such as about 20 atmospheres. 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 prior art patents shows anything about how the bismuth component is uniformly contained in the catalyst itself. In the production of low-pressure catalysts according to U.S. Pat. No. 3,650,985, if bismuth oxide carbonate is added separately to the preformed malachite,
It has been found that it separates in the final formed catalyst, giving unsatisfactory results. It would therefore be desirable to have a satisfactory method of co-precipitating bismuth in the catalyst precursor basic copper carbonate or malachite. Basic copper carbonate known as malachite
Cu ₂ (OH) ₂ CO ₃ is commonly produced by one of two precipitation methods. The first method is to neutralize a solution of a copper salt, such as copper nitrate or copper chloride, to a pH of 7.0 with sodium or potassium carbonate or bicarbonate. Initially hydrated copper carbonate i.e. amorphous
CuCO ₃ .x(H ₂ O) precipitates in the form of a viscous gelatinous substance, which upon heating desorbs CO ₂ and is slowly 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 (μ) to more than 25 μ. 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 for precipitating malachite is to add the copper solution described above and the carbonate neutralizer described above simultaneously with stirring to maintain the PH 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 30μ. As with the first method of adding carbonate neutralizers to the copper solution described above, 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, where the bismuth component remains therein and remains effective in inhibiting cuprene formation. Co-precipitated basic copper carbonate-bismuth particles can be used to produce a cuprous acetylide complex which is particularly useful as an ethynylation catalyst in the production of 1,4-butynediol. In some embodiments, the present invention essentially has the general formula (CuC ₂ ) _w (CH ₂ O) _x (C ₂ H ₂ ) _y (H ₂ O) _z −Bi (wherein, when w=4 x=0.24~4.0,y
copper, carbon, hydrogen, oxygen and bismuth in proportions corresponding to reacting acetylene and formaldehyde in the presence of a particulate cuprous acetylide complex, the complex particles having a total surface area of at least 5 m ² /g and an average particle cross-sectional dimension of at least 10 microns. An object of the present invention is to provide a method for producing 1,4-butynediol, which is characterized by the following. The catalyst precursor useful in the process of the invention is made in three steps. Hydrated copper carbonate particles are precipitated by first adding a solution of a cupric salt and a solution of an alkali metal carbonate or bicarbonate to water to form a reaction mixture. The solutions are proportioned to keep 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. Copper, bismuth and carbonate are then added and more malachite is precipitated on these transformed nuclei. Nucleated crystal grains and agglomerates of such grains
grow with bismuth uniformly mixed into their 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 sodium bicarbonate in proportions to maintain the pH in the range of about 5.0 to 8.0 until the crystallite agglomerate has an average cross-sectional dimension of at least about 10 microns. Add each solution. 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 as ethynylation catalysts to prepare cuprous acetylide complexes, which are particularly useful in the preparation of 1,4-butynediol. The basic copper-bismuth carbonate particles are treated as a slurry in an aqueous medium at 50 DEG to 120 DEG C. simultaneously with formaldehyde and acetylene at a partial pressure of not more than 2 atmospheres. Its aqueous medium is 3 to 10 at the onset of action.
It has a pH of Preferably, the reaction is continued until all of the copper precursor has been converted to cuprous acetylide complex. It is desirable that the medium in which this action takes place has a pH in the range of 5 to 8, at least initially. The generated catalyst _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 to 2.80, and bismuth is present in an amount of 1 to 5%). The complex particles have a total surface area of at least 5 m ² /g and an average particle cross-sectional size of at least 10 μ. Preferably the particulate complexes have a total area of 15 to 75 m ² /g, the average particle cross-sectional size ranges from 10 to 40 μ, 20 to 66% copper, 2 to 12.5 carbon atoms per copper atom , 0.2-2 hydrogen atoms per carbon atom, 0.1-1 oxygen atoms per carbon atom and 2-4% bismuth. Compared to the conventional method for producing basic copper carbonate crystals,
Method 1 above utilizes rapid precipitation of hydrated copper carbonate, followed by nucleation and conversion of hydrated copper carbonate to basic copper carbonate (malachite). The nucleation and transformation is facilitated by elevated temperatures, such as 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 tube, neutralizer and bismuth readily combine to produce a fairly uniform and uniform dispersion of bismuth into the large particle size basic copper carbonate crystalline particles. This crystal growth inhibits the initial formation of gelatinous hydrated copper carbonate. If the complete production of basic copper carbonate crystals, including precipitation formation, nucleation and growth, is carried out at elevated temperatures, for example above 60°C, 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 reality, 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 homogeneously contained in the basic copper carbonate produced in this process and is used as an ethynylation catalyst during or after the formation of the carbonate. There is a tendency for the carbonate salt to separate during any use to form the cuprous acetylide complex. It is therefore important to use the above method to produce a basic copper carbonate-bismuth co-precipitate to be used in preparing the ethynylation catalyst. To produce crystallites and agglomerates of smaller size, nucleation can be carried out at lower temperatures followed by increasing the temperature above 60°C, resulting in relatively rapid conversion and growth and uniform dispersion of bismuth. I can do it. To produce larger sized crystallites and agglomerates, nucleation is also carried out at higher temperatures, such as above 60°. If the PH increases by at least 10 units between the nucleation and growth stages, greater uniformity in particle size can be achieved. 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 at a pH of 3, the reaction product forms as a thick gel as the pH increases to 41/2. The subsequent PH increase and agitation transforms the gel into malachite while breaking it, 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. PH
If it is less than 5.0, gel formation becomes difficult. Sodium iodide can be added separately during catalyst formation. This produces some bismuth oxyiodide in the catalyst, which acts as another inhibitor to cuprene formation. Preferably, the catalyst has an agglomerate size of about 15-20 microns. Larger particles are advantageous over smaller particles because they filter and dry more quickly and do not cause dusting and banding during settling. The agglomerate size of 50μ is too large than desired as the activity of the catalyst is reduced. Catalyst particles that are too small make filtering difficult. The size of the agglomerates can be easily controlled by adjusting the temperature and pH of 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 reactor 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 fine particles which themselves are difficult to detect. Such separation also tends to deactivate the bismuth in the catalyst. At solubility levels of about 0.5 ppm 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, 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 crystal is growing, its pH 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 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 butine diol synthesis, substantial improvements in catalyst overcapacity and stability result. Ru. Bismuth-containing malachite is produced using an initial nucleation method to produce 1%, 2%, 3%, and 4% bismuth-containing malachite.
%, 8%, 10% and 15% bismuth concentrations. The resulting malachite is then used to produce an ethynylation catalyst. The catalyst thus obtained is then subjected to long-term life testing to determine its improved stability and performance as indicated by the absence of cuprene formation. 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. Cuprene is easily detected by its copper color, which commonly floats on the surface of formaldehyde-water solutions 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. 5 more
% bismuth in the form of bismuth subcarbonate with bismuth-free malachite and then converting the mixture 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. for a short period of time (e.g. up to about 1/2 hour) at an elevated temperature, e.g. 70 to 95°C. Bismuth additions of 5% and above result in some amount of bismuth separating from the catalyst after extended 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 of the catalyst obtained by the present invention is more easily processed. In butyne diol production processes where the catalyst system acts as a slurry and the product is removed by a candle filter, larger particle sizes can increase overrate. Reference Example 1 Malachite - 4% Bi (cold start) Crystalline particulate synthetic malachite containing 4% bismuth is produced as follows. Two liquid streams are added simultaneously to a reaction vessel containing 300 c.c. of water. One stream is a saturated aqueous solution of Na ₂ CO ₃ and the other is 100 _g of Cu(NO ₃ ) 2.3H ₂ O, Bi
(NO ₃ ) ₃・5H ₂ O2.32g, HNO ₃ 10c.c. and H ₂ O90c.c.
It is an aqueous solution containing. If these liquid streams are added at a rate that continuously maintains the pH in the precipitation vessel at about 6.5, and heat is gradually applied from the beginning, precipitation will begin. The following table shows the solution addition rate, the time from the start of the addition and the temperature of the reaction mixture, determined for the copper nitrate solution still to be added.

[Table] The reaction product is aged until a pH of 8.0 is reached, then filtered and dried. The particles have an average cross-sectional size of 15-20μ. The product contains 4% bismuth homogeneously dispersed in crystalline particles. Add only about 14 to 1/3 of the reactants until nucleation and transformation (although they may occur simultaneously) and then add the remaining reactants after nucleation to form the bismuth-containing malachite. It is desirable to grow crystals. Such crystals can be used to produce cuprous acetylide complexes that can be used to produce 1,4-butynediol. Reference Example 2 Malachite - 3% Bi (cold start) Crystalline particulate synthetic malachite containing 3% bismuth is produced according to Reference Example 1, but with the exception of
Use 1.74 g of Bi(NO ₃ ) _{3.5H 2} O. The following table shows data similar to that of Reference Example 1,
And also give the indicated PH several times during the reaction.

[Front] is malachite
converted to
Change pH to 7.5
)

[Table] Nucleation is achieved at PH 6.5 and then the PH is raised to 7.5 to grow the crystal. Finish crystallization at PH6.8 to make all malachite insoluble. The product is then aged at pH 8.0, washed, filtered and dried. The resulting product has particles having a cross-sectional dimension of 15-25 microns and containing well-dispersed bismuth at a level of 3%. Such products can be used to produce cuprous acetylide complexes which can be used to produce 1,4-butynediol. Reference Example 3 Catalyst Production In a typical catalyst production, 45 g of malachite containing 3% bismuth and 25 g of Cu were mixed at 37%
It is placed in a glass reactor with a jacket heater along with 600 g of formaldehyde and 2 g of CaCO ₃ to neutralize the formic acid formed. _N2 using a sintered glass frit to distribute the gas
A stream of C ₂ H ₂ diluted with C 2 H 2 is passed through the container. Control the temperature between 70 and 80℃ and the pressure between 4~
Control to 5peig. _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 C ₂ H ₂ and additional C ₂ H ₂ and N ₂ are added to maintain pressure. _{The C2H2} concentration in the exhaust gas, as measured by gas chromatography, is generally kept in the range of 2-5% by volume to obtain the most active catalyst. After all CO ₂ has been removed, 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. Example 1. Preparation of 4-butynediol The catalyst prepared in Reference Example 3 is placed in a jacketed container containing 600 c.c. 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. Acetylene is continuously fed at the same time as the 37% formaldehyde solution is fed to keep the formaldehyde concentration at a steady state of 10%. The product 1,4-butyldiol is passed through a sintered glass filter at least
The catalyst remains in the reactor as it is continuously recovered with a yield of 95%. A solution of sodium bicarbonate is added continuously to maintain the PH between 6.0 and 6.2 as determined by PH test in the reactor. Maintain total reactor pressure at 5 psig. The activity is (consumed
It is measured as (weight units of C ₂ H ₂ )/time/(weight units of copper in the reactor) and is calculated continuously from the consumption rate of formaldehyde. Life test is almost
The system is run for 100 hours or more, after which the system is cooled, the catalyst is recovered, filtered and washed to remove reaction components 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 aqueous layer, below which the evaluated catalyst is stored. The table below summarizes the results of life tests conducted using cuprous acetylide catalysts. 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 coprecipitated with malachite (tests 11 and 12) are excluded. Catalysts containing 2%, 5% and 15% bismuth, even when exposed to elevated temperatures in the absence of acetylene,
No subsequent formation of harmful cuprene is observed.

【table】

[Table]

[Table] Without
(BiO) ₂ CO ₃
maracay
add to
12 4 90 0.75 Small amount Precipitation at room temperature
let, Bi
separates

Claims (1)

[Claims] 1 Essentially the general formula (CuC ₂ ) _w (CH ₂ O) _x (C ₂ H ₂ ) _y (H ₂ O) _z −Bi (wherein, when w=4, x= 0.24~4.0,y
copper, carbon, hydrogen, oxygen and bismuth in proportions corresponding to reacting acetylene and formaldehyde in the presence of a particulate cuprous acetylide complex, the complex particles having a total surface area of at least 5 m ² /g and an average particle cross-sectional dimension of at least 10 microns. A method for producing 1,4-butynediol, characterized by: