SU1223840A3 - Method of producing formic acid - Google Patents

Abstract

1. The method of formic acid hydrolysis of methyl formate in the liquid phase when heated, characterized by the fact that, with a chain of simplification of the process and increase. the yield of the target product, methyl formate and water are introduced into the reaction zone at a pressure of 5 to 13 atm. 90-120 ° C and a molar ratio of 1.5-10: 1, respectively, of 0.3-20 minutes until the degree of hydrolysis of methyl formate reaches 95%, after which the resulting mixture is transferred to a low pressure zone in which pressure is maintained 0.53-1 atm, where, the excess methyl formate evaporates and the remaining: liquid is cooled, which is transferred to a distillation column with a pressure of 10-700 mm Hg. where the aqueous formic acid remaining in the bottom is separated, and the methyl formate, isolated as a distillate, and the water obtained after distillation of the aqueous formic acid are recirculated to the reaction zone. WITH gjnf

Description

2. A method of producing formic acid by hydrolysis of methyl formate in the liquid phase with heating, characterized in that, in order to simplify the process and increase the yield of the target product, methyl formate and water in the form of steam at a ratio of methane formate: water equal to 0.5 -3.0: 1, respectively, is passed into the pre-hydrolyzer at 90-140 ° C and a pressure of 5-18 atm, after which methyl-fommate and yuda are added to the mixture to a molar ratio of 1.5-10: 1 and introduced into the reaction zone with a pressure of 5–18 atm and 90–140 s for 0.3–20 min to attain the degree

Claims (6)

I This invention relates to organic chemistry, specifically to a highly purified formic acid process widely used in the chemical industry. The purpose of the invention is to simplify the process and increase the yield of the target product. Figs, 1 and 2 show diagrams of a continuous process for the production of formic acid. The proposed method is based on acid hydrolysis of methyl formate in the absence of solvents, with formic acid bluing as a catalyst, which forms during the reaction (in the examples; 1-6 amounts of substances are given in pounds per hour, only 11% of the material is given) . Example 1, Pre-hydrolyzer 1 is fed through lines 2 and 3 with 3078 parts of methyl formate to 1340 parts of water vapor and water. The preconductor is a tubular reactor, fused with glass strains, operating at 10 atm and. . The mole ratio of methyl formate: water is 0.7; 1. In the pre-hydrolyzer, 1460 parts of formic acid are formed, 320 parts of methanol and 1160 parts of water, 2478 parts of methyl formate remain unreacted. The resulting stream is fed through line 4 to main hydrolyzer 5 along with recirculated flows of lines 6-8, which have the composition shown in the table. hydrolysis of metipformate 95%, after which. The mixture is transferred to a low pressure zone in which a pressure of 0.53-2 atm is maintained, after which the product is transferred to a distillation column with a pressure of 10-700 mm Hg. where the aqueous formic acid remaining in the bottom is separated, and the methyl formate, isolated as a distillate, and the water obtained after the distillation of aqueous formic acid are recycled to the reaction zone. 3. The method according to claim 1, wherein t and h and y and y so that the atmospheric pressure is maintained in the low pressure zone. Lini Colpgonents, h I Methyl- Water Ants-, Methyl-1formate and acid ilotaspir 1118 The total charge to the master hydrolyzer 5 has a molar ratio of methyl formate: water of 2.4: 1. This reactor operates at 120 ° C 9 atm. The formic acid produced in the pre-hydrolyzer 1 serves as a catalyst for the reaction to be carried out in the main hydrolyzer 5. Due to strict adherence to temperature and. Dagheni hydrolysis reaction reaches 95%. chemical equilibrium after 20 s. The reaction product from the main hydrolyzer 5, containing, including: formic acid 2645; methyl alcohol 2013; methyl formate 16116 and water 1597 is fed through line 9 to the distant tank JO (low pressure zone), which operates at atmospheric pressure. In tank 10 a significant part of the non-reactive methyl formate, namely 6088 hours, distilled through line 6, the remaining liquid was rapidly cooled. The vapor is recirculated to the main hydrolyser 5. The liquid passes through line 11 to a low pressure distributive column 12, a steel column lined with glass plates, filled with braided glass mats having a volume sufficient to minimize fluid retention. Distillation column 12 operates at. 400 mm Hg, Art. and the temperature of the cube. The temperature of the distillation residues of the column is 22 ° C, the reflux ratio is 0.6-1.0. Distilling out a significant amount of methyl formate in the low pressure zone 10 allows the distillation column 12 to be controlled at a low reflux ratio, at a low temperature and with minimal contact time. Accordingly, slight transesterification is observed (less than 0.1% formic acid and methanol). In contrast, if we exclude the flash phase, then the l / 20% formic acid fed to the first distillation column is transesterified. In addition, the low temperature minimizes corrosion. Distillate from column 12, containing 10,028 parts of methyl formate and 1,641 parts of methyl alcohol, is passed through line 13 into. second distillation column 14. This column operates at 1.7 atm, the temperature in the cube is 77 ° C and the distillation temperature is 50 ° C, lined with glass plates and filled with glass mats. Practically pure methanol (1641 parts) is discharged as a residue and is sent to the storage through line 15. The overhead of methyl formate is recycled through line 7 to the main hydrolyzer 5. The rest is 2360 parts of formic acid and 1535 parts of water, from the first consoles 12 are fed to the third glass-lined distillate of the distillation column 16 via line 17. One third distantion of the 16-pillar column 16 is filled with glass mats and operates at 2.6 atm, the temperature of the cube is 142 ° С and the distillate is at 131 ° C. Water vapor overhead, consisting of water, recirculated It is fed through line 8 to the main hydrolyser 5. The residue is removed through line 18 and consists of 2360 parts of formic acid and 417 parts of water, namely, 85% of formic acid. The total amount of methyl formate which entered into the reaction is 600 hours in the pre-hydrolyzer and 2473 hours in the main hydrolyzer. Therefore, the total amount of used methyl formate is 3,078 hours, 5 Q 5 0 5 five 0 five 0 0 which is equivalent to 2360 parts of formic acid and corresponds to a yield of 100%. Example 2. In preliminary hydrolyzer 1 along line m 2 and 3 (FIG. 1), 1197 h, megiloformate and 718 h, of water are supplied. The resulting product contains, including: formic acid 92; methanol 64; methyl formate 1077; water 632. The TeMnepaTj pa in the preliminary hydrolyzer is 90 ° C, a pressure of more than 5 atm h the molar ratio of methyl formate: water is 0.5: 1, This mixture enters through line 4 to the main hydrolyzer 5, to which an additional 2870 parts of methyl formate is added through line 7, the resulting liquid product contains 681 parts of formic acid n 474 parts of methanol along with 2,700 parts of methyl formate and 452 hours. water, which corresponds to conversion to formic acid over 95% of the equilibrium value. A pressure of 8 atm and a temperature of 127 C is maintained in hydrolysis. The product enters the distant receptacle 10 at an absolute pressure of 400 mm Hg. Art., and at the same time 60% of methyl formate is evaporated. The liquid remaining in the distilled vessel contains, including: methyl formate 1080; formic acid 394; methanol 631; water 422. This liquid is then fed to a low pressure column 12 for distillation at a pressure of 400 mm Hg. Example 3. Some total. Technological and economic benefits can be achieved by using high concentrations of methyl formate in the feedstock entering the hydrolyser. 12,000 parts of methyl formate and 360 parts of water are fed to the main hydrolyser 5 along lines 2 and 3, respectively (FIG. 2). The product from the reactor contains, for example, formic acid 650, methyl formate 11154, methanol 451 and water 106, and the conversion of the base mineral is 95% of the equilibrium value. In the reactor, the pressure is maintained at 13 atm and the temperature is 120 ° C. The product enters the distant vessel (low pressure zone 10 at atmospheric pressure; moreover, it has been established that 38% of unreacted methyl formate evaporates). : methyl formate 6916; methanol 401; formic acid 620, and water 431, enters a low pressure distillation column 12, which maintains an operating pressure of 700 mmHg. Art. A 60% solution of formic acid in water is removed from the bottom of the distillation column, while the remaining methyl formate and methanol are taken as the overhead. Methyl formate and methanol are separated as in Example 1 in a second distillation column 14. five  The formic acid is concentrated according to Example 1 in the third dt of the column 3-6. Example 4. The reaction in the hydrolyzer is carried out at 90 ° C. The pre-hydrolyzer J receives a mixture of 120 parts of methyl forltate and 36 hours of water; the reaction product contains 23 parts of formic acid and 16 parts of methanol, along with 90 parts of methyl formate and 27 parts of water. This product is mixed with 1860 parts of methyl formate and 360 parts of water before entering the main hydrolyzer 5, in total The ratio is methyl formate: water 1.5: 1. The contact time in each hydrolyzer is 20 m. The resulting product contains 377 parts m of rabiago acid (which is 96% of the equilibrium value) and 249 parts of water along with 1488 parts of methyl formate and 262 hours of methanol. A pressure of 5 atm is maintained in the hydrolysis unit. The product from the pedrolizer enters the distant tank 10 at a pressure of 2 atm, and 25% of methyl formate is recovered from this tank as vapor. The liquid from the distant reservoir 10 is distilled in a low pressure digtillation column 12 at a pressure of 10 mm Hg. Art., and Poluchang bottom product -358 h. mz rabynoy acid in the form of a 60% aqueous solution of formic acid. This reaction consumes 492 parts of methyl formate, which is equivalent to 377 hours, of formic acid, and a total yield of formic acid is obtained, 95%. Example 5. In the preliminary ... gadroliser via line 2 receives 360 parts of methyl formate, which is well CMeun-iBaei from 36 parts of water, coming through line 3 (in a 3.0: 1 molar ratio). Set the temperature to 140 ° C and maintain a pressure of 18 atm. The product of pre-hydrolyzer 1 contains 24 h, formic acid. Then, the product from the interrupter head is mixed with 2640 parts of methyl formate and 54 hours, of water, so that in the total total feedstock of the main hydrolyzer 5 molar ratio methyl formate: water cocTaBj.sino 10: 1, the product g of shredder 5 contains 161 hours formic acid and 2790 parts of methyl formate, which corresponds to a conversion of 95% of the equilibrium value. The temperature in the main hydraulicizer 5 is 18 atm. This product enters the distillation tank 10, where it is stripped at: atmosphere. Mr. Dave A part (1395 parts) of metnoformate evaporates, and the liquid remaining in the distant tank 10 contains h. 38406  Miat 1395, water 24, formic acid 155, methanol 104. This liquid is continuously fed to a low pressure distillation column 12, in which a working pressure of 700 mm Hg is maintained. Art. Methyl formate and methanol were separated from a 86% solution of formic acid in water. Distillate containing 1395 parts of methyl formate and 104 parts of methanol. Enters the second distillation column 14 for separation. This column operates at a pressure of 1.7 atm, and the distillate temperature is 50 ° C. From this column, 1,395 parts of methyl formate are returned to the hydrolyzer reactor 5 5 and 1395 hours of methyl formate is returned from the distant reservoir 10. A solution of formic acid (86%) is fed into the concentrating column, if necessary, or directly into the storage tank of the product. In this process: 210 parts of methyl formate reacting are equivalent to 161 parts of formic acid. In hydrolyzers, 161 part formic is formed. acids and, therefore, the yield during the passage through hydrolyzers I and 5 is 100%, Example 6. Using the main hydrolyzer 5, it gives 3600 parts of methyl formate and 720 parts of water along the line m 2 and 30 3 respectively. Temperature in the hydrolyzer is 90 C, pressure is 5 atm. The contact time of the reaction mixture is 20 minutes, and the reaction proceeds to 95% conversion from the equilibrium value. At the outlet of the reactor mixture , has the composition, h .: methyl formate 2711, water 453, methanol 474, turvic acid 682. This product is nooiwaeT in -detachment capacity 10 at a pressure of 400 mm Hg. it was found that 45% of the unreacted Q of methyl mermate evaporates. Remaining liquid in the distant reservoir 10, containing, including: methyl formate 149.1, water 418, methanol 404, formic 45 acid 632, fed to the low pressure disgilatory column 12, distilled at 10 mm Hg. Art. and removing from the bottom of the low pressure distillation column a 60% solution of formic acid in water. 889 parts of methyl formate enter into the reaction, which is equivalent to 682 parts of formic acid. The yield of acid from: hydrolyzer is 00%. From the bottom of the distillation zone 12 low gj pressure can be distinguished 632 parts of formic acid or 93% of the total hydrolysis product. 7 13 / 7 t 98 11 12 8-G 15 sixteen / 17 Compiled by M. Kulish Editor A. ShishkinTehred I. Veres Corrector S. Shekmar Order 1729/62 Circulation 379Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Branch PPP Patent, Uzhgorod, st. Project, 4 FIG. 2 rg /