JPH0419979B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing ethylene glycol from methanol. Oil, which is in decline in production, is being put aside and emphasis is being placed on the use of syngas as a starting material for various chemicals such as methanol, formaldehyde and ethylene glycol in place of expensive oil. The advantage of syngas is that it can be produced from raw materials other than petroleum, such as natural gas or coal and possibly oil shale and tar sand. An example of an industrial method for producing ethylene glycol using synthesis gas as a starting material is to react formaldehyde with carbon monoxide and water at high pressure (more than 300 atmospheres) in the presence of an acid catalyst. This is a method of reacting to produce methyl ester, which is then converted to glycol by catalytic hydrogenation. Kotskaril April 13, 1943
U.S. Pat. No. 2,316,564, issued on April 4, 1939 to Larson, and U.S. Pat. No. 2,152,852 to Lauder, issued on April 4, 1939;
U.S. Patent No. 2,385,448, published June 9, 1942;
See US Pat. No. 2,331,094, published October 5, 1943. Another method of using synthesis gas for ethylene glycol production is the methanol carbon monoxide reaction using a rhodium catalyzed high pressure process. U.S. Pat. No. 4,115,428 to Vaidar et al. and September 1978 to Kosbey et al.
See U.S. Pat. No. 4,115,433, published on the 19th. The important thing about the ethylene glycol manufacturing method announced here is that the oxidative dimerization or dehydration dimerization of various organic compounds using hydrogen peroxide is a very simple process developed by free radical theorist MS Karlasch and his students. It is an old method. This work became the basis for Zuzu and later free radical chemistry. Carlatsushi et al. reported in JACS 16, 15, 1943 that the dehydration dimerization of acetic acid to succinic acid by acetyl peroxide was 50 mol% based on acetyl peroxide.
Usage selectivity (usage selectivity =
It has been reported that this can be done by dividing the number of moles of dehydrated dimer produced/the number of moles of peroxide changed. Isobenzoic acid produced tetramethylsuccinic acid with a utilization selectivity of 42.4 mol%. reported in J.Org.Chem. 10, 386, 1945 that the ester methylchloroacetate was dimerized to dimethylchlorosuccinate with acetyl peroxide with a utilization selectivity of 41%.
In J.Org.Chem. 10, 401, 1945, cumene and ethylbenzene were dimerized with acetyl peroxide to give 61.9 mol% of each.
321 mol% of these dehydrated dimers. Wiles et al., I.E&C, August 1949, page 1682, report the efficiency of di-t-butyl peroxide and 2,2-bis(t-butylperoxy)butane for cumene dimerization. Dimerization of the benzoate ester of benzyl alcohol with di-t-butyl peroxide to the corresponding glycol, diphenylene glycol, to the dibenzoate ester is reported in Last et al., JACS 70, 3258 (1948). There are numerous examples in the literature of producing very low concentrations of dehydrated dimer with utilization selectivity typically between 20 and 50 mole percent based on consumed peroxide. These selectivities are generally too low for methods considered for industrial development. Two reports of peroxide-using reactions with respect to ethylene glycol need to be mentioned. The first is Angew.Chem.
72, 1960, No. 21, pages 779-780, a mixture of di-tert-butyl peroxide and methanol at a ratio of 1:20.
in an autoclave or under reflux in a molar ratio of
This method involves heating at 140°C for 10 hours. An ethylene glycol yield of 26% was reported, and it is said that the yield increases with an increase in excess alcohol. Another reaction method to ethylene glycol that is more important in relation to the second invention is described by Oyama, J.
Org. Chem. 30, 2429-2432, July 1965. In particular, Oyama has 9 moles of methanol, 15
% formaldehyde aqueous solution and t-butyl peroxide (di-tert-butyl peroxide) at 140°C for 12 hours to produce 0.21 mole of ethylene glycol (top right column of table on page 2430)
and the following is written just below the table: ``The yield of ethylene glycol in the reaction of formaldehyde and methanol is higher than the yield of the dimerization reaction that occurs with t-butyl peroxide of methanol. The facts suggest that the hydroxymethyl group (D) adds to formaldehyde.'' Oyama gives a detailed description of the products obtained from carrying out this reaction, and describes this in the ``Experimental'' section on page 2431 (especially the title of this section). is the "reaction of methanol and formaldehyde" and "dimerization of methanol" is on page 2432), compared to the dehydration and dimerization of methanol in the presence of t-butyl peroxide and the absence of formaldehyde. . The yield of ethylene glycol obtained by Oyama is quite low. Oyama's only test of the use of methanol (the above reaction of methanol, aqueous formaldehyde and t-butyl peroxide at 140°C for 12 hours) produced only 1.86% by weight of ethylene glycol. The above reaction can produce ethylene glycol in a higher yield by substantially reducing the amount of organic peroxide used compared to the amount of formaldehyde and methanol used in Oyama. Furthermore, the increase in the amount of methanol and decrease in the amount of water compared to the other components in the reaction mixture compared to the amount of Oyama used also appears to contribute to the production of higher yields of ethylene glycol. Therefore, for example, if a mixture of 78.5% by weight methanol, 1.5% by weight di-tert-butyl peroxide, 6.9% by weight formaldehyde and 13.1% by weight water is heated at 155°C for 2 hours, a yield of 4.5% by weight will be produced in the reaction mixture. Ethylene glycol is obtained.
This corresponds to a yield of about 71 moles of ethylene glycol per mole of t-tert-butyl peroxide used. (Oyama uses ethylene glycol per mole of di-tert-butyl peroxide in the reaction.
0.466 mol). This improved method is detailed in US patent application Ser. No. 183,537, filed September 2, 1980. U.S. Patent Application No. filed July 28, 1981
No. 286721 states that in the presence of methanol and organic peroxide alone or formaldehyde and water, by-product formation in the presence of a basic substance in an amount sufficient to reduce the hydrogen ions produced during the reaction significantly degrades ethylene glycol. A method for producing ethylene glycol from the reaction of methanol and organic peroxide without reduction in production is described. The basic material in this application reduced the acids that contact the methylal formation from methanol and formaldehyde, such as formic acid, formed during the formation. Minimizing methylal formation is highly desirable to avoid the extremely large or expensive distillations required to purify ethylene glycol products. In accordance with the present invention, ethylene glycol is produced by the reaction of methanol, an organic peroxide in an amount of greater than 6 to about 25% by weight, formaldehyde, and about 0.5 to about 35% by weight of water, based on the weight of the reaction mixture. Ru. The amount of water used to obtain good results depends on the amount of peroxide used. The amount of ethylene glycol produced by this method is 40.5 methanol based on the weight of the reaction mixture described in the Oyama literature.
%, formaldehyde 7.55%, di-tert-butyl peroxide 9.18% and water 42.77%. Reducing the water content of the reaction to below 35% improves the amount of ethylene glycol to di-tert-butyl peroxide (on a molar ratio basis) than in the Oyama literature, which uses peroxide amounts greater than 6 and up to about 25%. be done. In addition to the ethylene glycol improvement, the process of the present invention provides a higher value (on a molar ratio basis) of tert-butyl alcohol to di-tert-butyl peroxide compared to the Oyama process. The acetone to di-tert-butyl peroxide molar ratio of the Oyama literature was generally higher than the acetone to di-tert-butyl peroxide molar ratio of the present invention. Tertiary butyl alcohol production is of particular importance for use as an intermediate for gasoline additives as well as as a gasoline additive itself. For purposes of the present invention, the range of amounts used for organic peroxide and water is as follows: greater than 6% by weight of peroxide water up to about 12% by weight.
About 0.5 to about 35% by weight More than about 12% to about 15% by weight
About 0.5 to about 25% by weight More than about 15% to about 20% by weight
About 0.5 to about 15% by weight More than about 20% to about 25% by weight
About 0.5 to about 10% by weight The amount of formaldehyde included in the reaction mixture is about 0.5 to about 13% by weight, preferably about 2 to about 12% by weight.
Weight%. The amount of methanol present in the reaction mixture is up to 100% of the remaining amount of reaction product. For example, the following ranges of amounts of reactants can be used: [Table] Preferred ranges are greater than 6 to about 10 5-10 2-12 68-87 This reaction generally takes place at a temperature of about 100 to about 200°C, preferably about 125° to about 175°C, for a time not exceeding about 8 hours. , usually about 0.25 to about 8 hours, preferably about
Residence times of 0.5 to about 4 hours are used. Generally, the higher the temperature, the shorter the reaction time required to bring the reaction to the desired completion state. There is little or no restriction on the pressure at which the reaction is run. Pressures between naturally occurring pressure and approximately 600 psig can be used. The organic peroxide used in the present invention has the formula: R-O-O-R', where R and R' each represent alkyl or aralkyl having from 3 to 12 carbon atoms. Organic peroxides that can be used are, for example, di-tert-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide and t-butyl ethylbenzyl peroxide. A preferred organic peroxide is tertiary butyl peroxide. Although inert solvents can be used in this method, in most cases it is better not to use them. Solvents that do not react under the operating conditions, such as benzene and tertiary butyl alcohol, can be used. If a solvent is used, it will normally be used in amounts up to about 25% by weight, based on the weight of the total reaction medium, although higher amounts may be used in some cases. The reaction can be carried out in a batch manner in which the initial reaction mixture is placed in a stirred autoclave, reacted, and then the entire reaction mixture is taken out and purified. Other batch systems include methanol, water and formaldehyde (usually mixed with a small amount of water) as the initial reaction mixture.
After adding a portion of the methanol and peroxide, formaldehyde and the remainder of the peroxide and, in some cases, a basic substance are successively added to the methanol reaction medium. After all of the reactant portions have been added and the reaction is allowed to continue until the desired reaction is complete, the reaction product is removed and purified. Another method is a semi-continuous process in which the methanol reaction medium is charged with the initial reaction mixture and additional amounts of reactants to complete the reaction and the product mixture is periodically removed from the reactor for purification. The continuous reaction is carried out in a reactor constructed such that reaction conditions create a glycol concentration gradient between the point of addition of the first portion of peroxide and formaldehyde and the point of withdrawal of the glycol-containing product. can be set. The subsequent portions of peroxide and formaldehyde are therefore added between the previous two points. For example, a continuous process may be carried out by flowing a liquid reaction medium through a pipe and adding portions of formaldehyde and peroxide reactants at intervals along the pipe to form a mobile reaction medium with a glycol concentration gradient as it flows through the pipe. . Thus, each individual portion of the reactants is added in a controlled manner along the pipe to the special transfer reaction medium until all of the reactants have been added. At the end of the pipe reactor, the conversion of each portion of the reactants in the reaction medium is complete and a product stream containing the desired amount of ethylene glycol is obtained. Also, a diaphragm reactor can be used containing a liquid reaction medium between the inlet of the initial feed stream and the outlet of the product stream, with additional portions of peroxide and formaldehyde added to provide a glycol concentration gradient. In either case, the product mixture is purified by conventional methods such as distillation or solvent extraction to the desired purity, preferably fiber grade, of ethylene glycol and tertiary butyl alcohol, methylalcohol,
By-products such as methylformate, glycerin and acetone are obtained. The following examples illustrate the invention. Examples 1-18 Methanol (MeOH) in a stirred autoclave,
An initial reaction mixture consisting of di-tert-butyl peroxide (DtBP), formaldehyde (CH ₂ O) and water was charged in the following manner: total but approximately 20% by weight of the initial charge into a stirred autoclave. of methanol, formaldehyde and water at room temperature. The mixture was heated to reaction temperature and the remaining 20% by weight solution of di-tert-butyl peroxide in methanol was added to the autoclave to initiate the reaction.
The reaction pressure was maintained at 500 psig with nitrogen. After the above reaction time, the resulting mixture was removed from the autoclave, and ethylene glycol (EG), acetone (A), and
It was analyzed for butyl alcohol (TBA), unreacted di-tert-butyl peroxide and other minor products. To compare the present invention with the method of the Oyama literature, Example 15 shows the results of the Oyama method.
The test was conducted at atmospheric pressure in a 304 stainless steel Hawk reactor charged with methanol, di-tert-butyl peroxide, formaldehyde, and water. The reactor was covered with a lid, placed in a constant temperature oil bath at a predetermined reaction temperature, and reacted for 1 hour at naturally occurring pressure. After the reaction time was completed, the reactor was rapidly cooled, evacuated, and the contents removed and analyzed for ethylene glycol, acetone, tert-butyl alcohol, unreacted di-tert-butyl peroxide, and other minor products. Examples 16, 17, and 18 show reaction results using 35.7 to 45 weight percent water with peroxide, formaldehyde, and methanol in a 304 stainless steel Hawk reactor. For each test 0.015% by weight of sodium bicarbonate was added to the initial reaction mixture. The reactor was capped and placed in a constant temperature oil bath at 155°C for 1 hour at autogenous pressure. After the reaction was completed, the reactor was rapidly cooled and evacuated, and the contents were removed and analyzed for ethylene glycol, acetone, tert-butyl alcohol, unreacted di-tert-butyl peroxide, and other minor products. In Example 16, ethylene glycol and unreacted di-tert-butyl peroxide were analyzed, but acetone and tert-butyl alcohol were not analyzed. All the results of the above examples are shown in the table. The table shows the initial charge composition, temperature, pressure, and reaction time used in the reaction. The results of Example 15 (Oyama's method) for the production of ethylene glycol were the same as those obtained in the literature.
If we compare the results of Example 15 with the results of Examples 1 to 14 of the present invention, it is important to note that all of Examples 1 to 14 have lower ethylene glycol vs. Butyl peroxide and tertiary
The molar ratio of butyl alcohol to di-tert-butyl peroxide is high. Regarding acetone, the molar ratio of acetone to di-tert-butyl peroxide in Examples 1-14 was greater than that in Example 15. Examples 16-18, which are outside the scope of the present invention, illustrate the use of 35% by weight or more of water in the reaction mixture. In accordance with the invention claimed in pending Application Serial No. 286721 filed on July 28, 1981, a base, i.e., 0.015% by weight of bicarbonate, has the effect of reducing the formation of by-product methylal and increasing the formation of ethylene glycol in the reaction mixture. Even though sodium was used, the weight percent of ethylene glycol produced in these examples was less than that obtained by Oyama's method. [Table] [Table] [Table] Charged di-tertiary butyl peroxide (wt%)
The results of Examples 1-18 are plotted in the accompanying figure, showing the correlation between the molar ratio of ethylene glycol to di-tert-butyl peroxide obtained at various amounts of water. In Example 13, there is only one point where the amount of water used is 2.3% by weight, so it was not plotted on the graph. The figure shows that as the amount of water is reduced, higher amounts of di-tert-butyl peroxide can be used to obtain better results than those of Oyama's method. Therefore, the percentage range of peroxide that can be used for a given water amount range is as follows: More than 6% peroxide water up to about 12% by weight About 0.5 to about 35% by weight More than about 12 to about 15% by weight to
About 0.5 to about 25% by weight More than about 15 to about 20% by weight
About 0.5 to about 15% by weight More than about 20 to about 25% by weight
About 0.5 to about 10% by weight Examples 19-22 These embodiments include formaldehyde (CH ₂ O) containing water (H ₂ O) in the presence of sodium bicarbonate (NaHCO ₃ ), di-tert-butyl peroxide (DtBP ) and methanol (MeOH)
Figure 2 illustrates the use of the same total amount of reactants in single-stage and multi-stage reactions in the production of ethyl glycol (EG) by the reaction of EG. The formaldehyde used in these examples contained 4.54 ppm sodium hydroxide per weight percent formaldehyde used. The reactor is 1 inch in diameter with a liquid capacity of approximately 85 ml.
It was made of 316 stainless steel pipe. In the first-stage reaction, all reaction components are placed in a reactor and sealed at a naturally occurring pressure of 155
Heated at ℃ for 1 hour. In multi-stage reactions, the reactants, di-
Tert-butyl peroxide, formaldehyde and a portion of water and sodium bicarbonate were initially added to a reactor containing all methanol and heated at 155°C for 1 hour. After 1 hour of reaction, an additional portion of reactants was added and the reaction was allowed to proceed for an additional hour. After 2 hours, the remainder of the reactant was added to the reactor and reacted for an additional hour. After completion of the first stage and each multistage reaction, the reactor was rapidly cooled, evacuated, and the contents were taken out and analyzed for ethylene glycol (EG) and other products by gas chromatography. The results of these examples are tabulated for the composition of the total amount of peroxide, formaldehyde and water charged to the methanol-containing reactor at various stages. Reactant usage was reported as weight percent of total material in the reactor up to that stage. The amount of ethylene glycol was reported as weight percent of the total product mixture. 【table】

[Brief explanation of drawings]

The accompanying figure is a curve diagram showing the relationship between the charged di-tert-butyl peroxide and the molar ratio of ethylene glycol to di-tert-butyl peroxide obtained at various amounts of water in the process of the invention. Di-tertiary butyl peroxide charged on the vertical axis (wt%)
The horizontal axis shows the molar ratio of ethylene glycol to di-tert-butyl peroxide.

Claims (1)

[Claims] 1. Organic peroxides and formaldehydes with the methanol formula in the presence of water: R-O-O-R' (where R and R' each represent alkyl or aralkyl having 3 to 12 carbon atoms) In the method for producing ethylene glycol by the reaction of ethylene glycol, based on the total weight of methanol, organic peroxide, formaldehyde and water in the initial reaction mixture, the following range: more than about 6% peroxide water and up to about 12% by weight
About 0.5 to about 35% by weight More than about 12 to about 15% by weight
About 0.5 to about 25% by weight More than about 15 to about 20% by weight
About 0.5 to about 15% by weight More than about 20 to about 25% by weight
An improved process characterized by the use of organic peroxide and water within about 0.5 to about 10% by weight. 2. The method according to claim 1, wherein the organic peroxide is di-tert-butyl peroxide. 3. The method according to claim 1, wherein the reaction time does not exceed 8 hours. 4. Claim 2, wherein the initial reaction mixture contains about 0.5 to about 13% by weight formaldehyde, the remainder being methanol, and the reaction temperature is about 100 to about 200°C and the reaction time is about 0.25 to about 8 hours. The method described in section. 5 The initial reaction mixture contains from about 41 to about 91.5% by weight methanol, from about 6 to about 12% by weight di-tertiary
butyl peroxide, containing about 0.5 to about 35% by weight water and about 2 to about 12% by weight formaldehyde, and having a reaction temperature of about 125°C to about 175°C.
and the reaction time is about 0.5 to about 4 hours. 6 The initial reaction mixture is about 48 to about 85.5 weight percent methanol, about 12 to about 15 weight percent di-tert-butyl peroxide, about 0.5 to about 25 weight percent water, and about 2 to about 12 weight percent formaldehyde. 3. The method of claim 2, wherein the reaction temperature is from about 125 to about 175°C and the reaction time is from about 0.5 to about 4 hours. 7 The initial reaction mixture is about 53 to about 82.5 weight percent methanol, about 15 to about 20 weight percent di-tert-butyl peroxide, about 0.5 to about 15 weight percent water, and about 2 to about 12 weight percent formaldehyde. 3. The method of claim 2, wherein the reaction temperature is 125 to 175°C and the reaction time is about 0.5 to about 4 hours. 8 The initial reaction mixture is about 53 to about 77.5 weight percent methanol, about 20 to about 25 weight percent di-tert-butyl peroxide, about 0.5 to about 10 weight percent water, and about 2 to about 12 weight percent formaldehyde. 3. The method of claim 2, wherein the reaction temperature is from 125 to about 175°C and the reaction time is from about 0.5 to about 4 hours. 9. The initial reaction mixture contains about 68 to about 87% by weight methanol, greater than 6 to about 10% by weight di-tert-butyl peroxide, about 2 to about 12% by weight formaldehyde, and about 5 to about 10% by weight. 3. The method of claim 2, comprising water and a reaction temperature of 125 to 175°C and a reaction time of about 0.5 to about 4 hours.