The method of producing formaldehyde
The invention relates to the technology of organic synthesis, and in particular to an improved process for the preparation of formalin used in chemical industry, medicine and agriculture. The method includes preparing spirtovodochnogo mixture by forced evaporation photometering mixture and mixing with abhasa, formaldehyde and air, overheating and passing through the silver catalyst at elevated temperature with subsequent absorption of the reaction gases with the formation of end product - formalin, and the evaporator serves the original methanol and abhas taken from the bottom of the absorption column at a temperature of 70-100And the upper part of the absorption column, and which introduces additional formaldehyde in the gas phase in the amount of 0,86-4.3 wt.% by weight of methanol, when the mass ratio of the original methanol to abhasa containing added formaldehyde of 1:(0.6 to 0.9), while the air supplied after receiving photometering gas mixture outside of the evaporator. The invention improves the quality of formalin and its concentration, reduce the expenditure norms methanol, prolong Sobranie refers to the technology of organic synthesis, in particular, to a method for formalin, which is used in chemical industry, agriculture and medicine.A method of obtaining formalin, including sparging air through the heated below the boiling point photometering mixture (see, for example, B., Narrogin, C. B. Narrogin. Technology for the production of formaldehyde from methanol. - Novosibirsk, 1995, S. 173-176,229-235).In the way the air at a given temperature is saturated vapors of methanol and water, is mixed with the stream of exhaust gases (gases after absorption columns. Received spirtovodochnogo mixture is sent to the superheater, and then served in the contact device, where the catalyst bed flow reaction conversion of methanol to formaldehyde and related products. The reaction gases are directed to podkonicky refrigerator, combined with the contact device, disposed where the reaction heat and then cooled to t=100-150With the reaction gases are directed into an absorption column, where due to irrigation water and condensing vapors formed trademarks of formalin (aqueous formaldehyde and unreacted methanol), which derive from the lower part of the column. Non-condensable gases (Ostara casing and, partially, with the circulating blower return in a process for the preparation of the working spirtovodochnogo mixture, and partly sent for disposal.The closest to a developed method of producing formaldehyde is a process involving the preparation photometering gas mixture by forced evaporation photometering mixture and mixing with abhasa, formaldehyde and air, overheating and passing through the silver catalyst at elevated temperature with subsequent absorption of the reaction gases with the formation of end product - formalin (see, for example, B., Narrogin, C. B. Narrogin. Technology for the production of formaldehyde from methanol. - Novosibirsk, 1995, S. 325, technological scheme of the company BASF).If push boiling in spartaaaaaa the required ratio of methanol, water and oxygen in the mixture is maintained independently from each other by means of self-regulation of the flows of air and exhaust gases.This system is less inertia and more convenient in operation compared to the first.However, when the air supply to the stage of evaporation of the methanol, as it is carried out in the described way, the conservation of the l:oxygen close to the boundaries of explosive concentrations therefore we have methanol largely diluted with water, which leads to the dilution of a trademark formalin water and does not allow to obtain a high concentration of formaldehyde in the product product.Introduction formaldehyde spastically in the liquid phase dictates the necessity of using any part of the commodity formalin or tar-water production formaldehyde resins, or return of methanol from plants processing of formalin, which leads to the inevitable introduction of the working mixture of related data streams impurities that are harmful to the catalyst used for the process of obtaining formaldehyde from methanol (in the process of formalin special requirements to the purity of the raw materials, methanol, water, air).Object of the invention is to improve the quality of formalin and its concentration, the decrease of expenditure norms methanol, increasing the service life of the catalyst and the maximum explosion process.This object is achieved by a method of producing formaldehyde, including the preparation photometering gas mixture by forced evaporation photometering mixture, mixed with abhasa, formaldehyde and air is th the resulting reaction gases with the formation of a commercial product, the distinctive feature of which is that the evaporator serves the original methanol and abhas taken from the bottom of the absorption column at a temperature of 70-100And the upper part of the absorption column, and which introduces additional formaldehyde in the gas phase in the amount of 0,86-4.3 wt.% by weight of methanol, when the mass ratio of the original methanol to abhasa containing added formaldehyde of 1: (0.6 to 0.9), while the air supplied after receiving photometering gas mixture outside of the evaporator.In the drawing given technological scheme for obtaining formalin.In the evaporator 1 serves methanol and demineralized water, and abhas taken from the bottom of the absorption column and the upper part.In the evaporator 1 of the original mixture is subjected to forced boiling. After certainareas obtained gas-vapor stream containing less than 1% vol. oxygen and saturated with phlegmatization in the form of water vapor, nitrogen, carbon dioxide and other inert gases contained in the exhaust gases are mixed outside of the evaporator 1 with the preheated air in the pipeline and served in the superheater 2, and then in contopus in podkonicky refrigerator 4, cooled to a temperature of 100-150With and received in the absorption column 5, where the formaldehyde, water vapor and residual methanol is condensed and absorbed by water with formation of commodity formalin, which is derived from a bottom part of the absorption column 5.Non-condensable gases - abgas from the top of column 5 with a residual content of water, methanol and formaldehyde with the circulating blower 6 is partially directed to the evaporator 1 to obtain a working photometering gas mixture, the rest of the flue gas is sent for disposal.In the circulation flow abhasa supplied to spastically 1, dispense part of abhasa taken from the bottom of the column 5 containing a certain amount has not yet absorbed formaldehyde vapours of methanol and water, the replacement of the source streams that are fed into spastically 1 or supplementing these threads in a mass ratio of methanol to abhasa containing added formaldehyde of 1: (0,6-0,9).Thus, in the evaporator, the working photometadata mixture enriched formaldehyde that is necessary to increase the degree of conversion of methanol and selectivity of the process formaldehy commodity formalin. The dosed quantity of additional formaldehyde in the ratio in the gas phase to the methanol must be within 0,86-4.3 wt.%.In addition, due to the fact that abgas taken from the bottom of the absorption column 5, is at a temperature of 70-100C (higher temperature gases in the upper part of the column), it is saturated to a greater extent water vapor, thereby reducing the amount of raw water supplied to the dilution of methanol, and to increase the concentration of produced commercial formalin.In order to avoid condensation of water vapor from the stream taken from the bottom of the column, when mixed with cooler flow from the upper part of the column last overheat the heater 7 to a temperature above the dew point.Example 1. To prepare photometering gas mixture in the evaporator 1 serving 2000 kg/hour of methanol and 810 kg/h of demineralized water (evaporation comes photometadata mixture with the concentration of methanol 71 wt.%). Outside of the evaporator 1 in the resulting gas-vapor stream is metered air 3700 kg/hour. In the mixing chamber of the evaporator 1 through the circulation pump 6 serves abgaz, part of the off-gases from the upper part of absorbtion circulation circuit, in the amount of 246 kg/hour. In this stream include formaldehyde 7.0 wt.%, methanol 2 wt.% water and 16 wt.%. The total number of abhasa is 1200 kg/h. In the contact device 5 by regulating the air supply keep the temperature 680-700C.Thus, in photometering gas mixture mass ratio of methanol : abhas is 1:0.6, the amount of formaldehyde accounts for 0.86 wt.% from the amount of methanol.Received after the evaporator photometering gas mixture overheat up to 110-120With and served in the contact device 3. Coming out of the contact apparatus, the reaction gases are cooled in polcontact the refrigerator 4 and a temperature of 130-150With serves in the absorption column 5. In the column from the reaction gases are absorbed formaldehyde, water, and unreacted methanol. Due to the supply of demineralized water for irrigation columns in the amount of 1150 kg/h, the content of formaldehyde in the formalin is brought to 37 wt.%, the amount of residual methanol is 1.1 wt.%, the rest is water.Rate of methanol in the process is 458 kg per 1 ton of produced 37% formalin. Maximum methanol and demineralized water in the evaporator 1, and temperature of the contact device 3 remain the same as in Example 1.Abgas served in the evaporator 1 in the amount of 572 kg/hour. In the flow of circulating abhasa metered portion of abhasa from the bottom of column 5 in quantity 1228 kg/hour. The composition dosed mixture is the same as in Example 1. The total number of abhasa is 1800 kg/h, and the mass ratio of methanol:abgas - 1:0,9.In photometering gas mixture, the quantity of formaldehyde is 4.3 wt.% from the amount of methanol. Air consumption for cooking photometering gas mixture is 3500 - 3700 kg/hour.When applying for irrigation columns 1250 kg/h of demineralized water mixture of formaldehyde: formaldehyde - 37 wt.%; methanol - 0.9 wt.%; water - the rest.Rate of methanol in the process is 450 kg per 1 ton of produced 37% formalin.The maximum attainable concentration of formaldehyde in the product under the same conditions as in Example 1, is 51 wt.%.In the proposed method maximizes the explosion process in comparison with the known methods of obtaining formalin due to the fact that, firstly, the air fed into photometering mixture outside of the evaporator; the vapor of methanol and water is served superheated above the dew point of the exhaust gases flow - abgaz, contain less than 1% oxygen, which allows to obtain the volume of certainparts explosion of the mixture below the lower explosive limit.The enrichment of the mixture with formaldehyde increases the degree of conversion of methanol and selectivity in the process, and in the process are not introduced impurities that adversely affect the lifetime of the catalyst.
ClaimsThe method of producing formaldehyde, including the preparation spirtovodochnogo mixture by forced evaporation photometering mixture and mixing with abhasa, formaldehyde and air, overheating and passing through the silver catalyst at elevated temperature with subsequent absorption of the reaction gases with the formation of end product - formalin, characterized in that the evaporator serves the original methanol and abhas taken from the bottom of the absorption column at a temperature of 70-1000And the upper part of the absorption column, and which introduces additional formaldehyde in the gas phase in the amount of 0,86-4.3 wt.% by weight of methanol, when the mass ratio of the original methanol to abhasa containing added formaldeh the La.
(a) the air supply and methanol in the evaporator, in which the methanol is evaporated, the formation of gas-phase mixture of methanol and air;
(b) interaction of gas-phase mixture of methanol and air over the catalyst at elevated temperature to obtain a reaction mixture containing formaldehyde formed by partial conversion of methanol and water vapors and noncondensable gases;
(c) passing the reaction mixture through at least one adsorption column where the above-mentioned mixture is absorbed in the aqueous solution flowing in the opposite direction;
(d) separation of the aqueous and non-condensable gases in the absorption columns;
(e) cooling and washing of non-condensable gases that carry small amounts of methanol and formaldehyde; and
(f) the fractional distillation of an aqueous solution with the appropriate Department of methanol
FIELD: industrial organic synthesis.
SUBSTANCE: process comprises providing alcohol-water-gas mixture via evaporation of water-methanol mixture, combining the latter with air and emission gas, catalytic dehydrogenation of methanol on silver catalyst at elevated temperature followed either absorption of formaldehyde from reaction gases or chemisorption thereof from indicated gases with urea solution in column to produce and recover formalin in case of absorption or urea-formaldehyde solution in case of chemisorption. Into absorption/chemisorption stage, preheated emission gas is supplied in weight proportion to methanol (0.25-6,8):1. Generally, emission gas is preheated to 50-130°C.
EFFECT: increased concentration of produced formalin or urea-formaldehyde solution, widened concentration control range, simplified equipment, and reduced fire risk.
2 cl, 1 dwg, 4 ex
FIELD: industrial organic synthesis.
SUBSTANCE: in presence of a process for production of methyl ethyl ketone widely applicable in petroleum processing and petrochemical industries at oil dewaxing and paraffin deoiling plants, in varnish-and-paint industry to produce polyurethane coatings, in wood processing industry to produce a variety of glues, in industrial rubber article industry, in perfumery, and in other areas. Process comprises 2-butanol/hydrogen peroxide reaction conducted at 20-100°C and butanol/peroxide molar ratio (1.0-13.0):1 on titanium silicate catalyst having MFI, MEL, or beta zeolite topology and containing 0.1 to 9.5% titanium, content of catalyst ranging from 0.01 to 20% based on the total weight of reaction medium. Thus formed methyl ethyl ketone is isolated from reaction medium via rectification in the form of azeotrope with water while unreacted 2-butanol with admixture of water is recycled to synthesis stage. Methyl ethyl ketone/water azeotrope is separated via extraction with organic solvent as extractant at extractant-to-azeotrope ratio (0.5-10):1 and number of extraction steps from 1 to 10. Extract is separated via rectification or distillation processes to recover commercial methyl ethyl ketone while returning extractant to separation stage.
EFFECT: increased yield of methyl ethyl ketone and reduced power consumption.
2 cl, 1 tbl
SUBSTANCE: invention pertains to the method of uninterrupted production of formalin and carbamide-formaldehyde concentrate. The method involves catalytic dehydrogenation of methanol with formation of formaldehyde-containing contact gases, in which there is separation of part of the formaldehyde in form of formalin, supply of contact gases for chemisorption of formaldehyde by a water solution of carbamide, obtaining of carbamide-formaldehyde concentrate with calculated molar ratios of formaldehyde to carbamide of (4.5-5.2):1. Separation of part of the contact gases in form of formalin is made by cooling the contact gases of dehydrogenation of methanol to temperature lower than the dew point of 50-80°C. The resulting condensate is removed in form of formalin, and the remaining part of contact gases is taken for chemisorption.
EFFECT: method increases quality and stabilisation of the mixture of formalin and carbamide-formaldehyde concentrate and simplifies the process.
1 dwg, 4 ex
SUBSTANCE: invention refers to electrochemical method of primary and secondary alcohol oxidation to related carbonyl compounds including preparation of mother solution at room temperature. Then salt 2,2,6,6-tetramethylpiperidine hydrochloride of general formula is added to electrolyte solution consisting of oxidised alcohol, water, methylene chloride, sodium chloride and sodium sulphate with electrolysis on platinum electrodes at current strength 1.5 A and temperature 20-25°C.
EFFECT: higher technological effectiveness of process combined with reduced time for producing high-yield end product.
SUBSTANCE: method involves preparation of a reaction mixture at room temperature consisting of the alcohol to be oxidised, sodium bicarbonate, an organic solvent and a nitroxyl radical. Electrolysis is carried out on platinum electrodes with current of 1 A and temperature of 20-25°C. Potassium iodide is added to the reaction mixture. The organic solvent used is dichloromethane and the nitroxyl radical used is 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxyl of formula: with ratio of alcohol to nitroxyl radical equal to 10:1.
EFFECT: invention ensures high output of end products a within short period of time and less expenses on electricity using a high-technology method.