Method of uninterrupted production of formalin and carbamide-formaldehyde concentrate

FIELD: chemistry.

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

 

The invention relates to the technology of production of formaldehyde and urea-formaldehyde concentrate and can be used in the chemical industry.

A known method for the production of formaldehyde, which consists in the catalytic dehydrogenation of methanol water column device with the receiving contact of the gases and the subsequent absorption of formaldehyde in the interaction of contact of the gases with liquid heat and obtaining aqueous solutions of formaldehyde is formalin /Begraben and other Technology formalin". Novosibirsk, 1995 s-296/.

The relative disadvantage of this method is that formaldehyde gases from the contact is fully transferred to the aqueous solution of formalin, which is an intermediate product for further processing into products formalin series.

A method of obtaining the urea-formaldehyde concentrate the chemisorption of formaldehyde from formaldehydefree contact of the gases obtained by the dehydrogenation of methanol on gelatomaltitolo catalyst 50-65%aqueous solution of urea. The process is carried out in a three column to obtain a urea-formaldehyde concentrate with adjustable content of uronic and trisonomy derivatives (RU patent No. 2142964, 08G 12/12).

The disadvantages of this method include the fact that% the SS chemical bonding of urea formaldehyde takes place in conditions of high temperatures (120-140° (C) in the lower part of the column, which leads to the formation of molecules branched structure, reducing consumer properties of the obtained product, as well as the fact that the entire formaldehyde contact of the gases is transferred in a single product - urea-formaldehyde concentrate.

The closest in technical essence and the achieved result is a continuous way to obtain a urea-formaldehyde concentrate, namely, that before chemisorption contact gases previously sent to formaldehyde absorption by water to form a concentrated aqueous solution of formaldehyde is formalin, as an intermediate product, which is then mixed with the urea-formaldehyde preconcentrator obtained in the process of chemisorption and having a molar ratio of formaldehyde and urea (1.9 to 4.0)is:1, obtained by mixing formaldehyde concentrate as a commercial product with a molar ratio of formaldehyde and urea (4,5÷5,2):1 (RU patent No. 2247129, 08G 12/12). Part of concentrated formalin diluted to obtain technical formalin water condensate formed after cooling the gases leaving the zone chemisorption.

Preconcentrate coming out of the process at the stage of chemisorption low ratio of formaldehyde and urea, t is aetsa intermediate product and requires bringing components to a specified ratio. Preconcentrate mixed with concentrated formalin obtained by absorption in the first stage of formaldehyde emissions with complicated dosing system intermediates that do not guarantee the stability of the composition and physico-chemical properties of the final product.

The objective of the invention is to improve the quality and stabilization of the composition of formaldehyde and urea-formaldehyde concentrate and process simplification scheme.

This object is achieved in that in the method of continuous receipt of formaldehyde and urea-formaldehyde concentrate, including catalytic dehydrogenation of methanol with education formaldehydefree contact of gases, of which there are part of formaldehyde in the form of formalin, the supply contact of the gases on the chemisorption of formaldehyde in an aqueous solution of urea, obtaining formaldehyde concentrate with the calculated molar ratio of formaldehyde and urea (4,5-5,2):1, characterized in that the selection of the formaldehyde from the contact of the gases in the form of formalin provide contact cooling gases dehydrogenation of methanol below the dew point to a temperature of 50-80°and chemisorption serves the remainder of the contact of gases obtaining after chemisorption of urea-formaldehyde concentrate with the calculated molar of sootnoshenie the M.

The method is as follows. Contact gases, obtained by catalytic dehydrogenation of methanol, come on cooling to a temperature below the dew point of the gases is condensed part of formaldehyde, water and residual methanol to form formaldehyde in a quantity and concentration, temperature-dependent cooling of the gases in the temperature range of 50-80°C. the Obtained formalin away after cooling in an independent product.

The cooled gases contact with the residual of the equilibrium vapor content of formaldehyde, water and methanol are sent to stage chemisorption aqueous solution of urea, where formaldehyde is chemically bonded with urea at a temperature of 50-70°With neutral or slightly alkaline medium at pH 6.5-9.0 in obtaining formaldehyde concentrate as a separate commercial product. The quantity of urea solution set of conditions for the maintenance of the urea-formaldehyde concentrate molar ratio of formaldehyde and urea (4,5-5,2):1.

The contact cooling of the gases occurs in the mixing apparatus representing a column apparatus Poppet, nozzle type or hollow scrubber, in which the contact gases pass from the bottom up. The condensation products are cooled and serves as a refrigerant is tivotogo to gas from the top down. When the gases contact with the cooled condensation products is cooling the gases below the dew point and condense the water vapor, formaldehyde and methanol, mixed with the circulating condensation products which are heated.

Circulating condensation products are cooled in the heat exchanger through the heat-conducting wall of any refrigerant, without mixing with it.

The contact cooling gases can be carried out either in a separate apparatus, or device, combined with the absorber or hemosorbent and representing its refrigerant-condensing section.

The drawing shows a variant of the circuit producing products with a standalone cooling device contact gases dehydrogenation of methanol.

Served in certainately 1 methanol and water is vaporized, mixed with air and gas mixture comes in contact device 2 with podkonicky refrigerator. In the contact device 2 on the catalyst is a dehydrogenation of methanol with education formaldehydefree gases. Contact gases in the overheated condition (temperature above dew point) receives the cooling apparatus 3.

In this apparatus the gases contacting with the flow of the condensation products circulating on the circuit: cube machine - circulation pump 5 - chilling the nick 6 - the upper part of the cooling apparatus 3, is cooled to a temperature below the dew point and condense water, formaldehyde and methanol, forming an aqueous solution of formaldehyde is formalin, which is taken from the circulating stream in the form of the finished product.

The remaining part of the contact gas is supplied to the column 4 chemisorption, where the interaction with the aqueous solution of urea forms a urea-formaldehyde concentrate, which derive from a bottom part of this column.

The remaining part of the contact gas is removed from the upper part of the column for recycling.

The essence of the method is illustrated by examples.

Example 1. Contact gases from the reactor for the dehydrogenation of methanol on tregenna silver catalyst in the amount of 12,500 kg/h with a temperature of 130°With, having in its composition (wt.%): formaldehyde - 20, methanol - 1,2, water - 20.5 and non-condensable gases is 58.3 (N2; CO; CO2; H2; O2), is directed to cooling below the dew point (for a given composition - 83° (C) to a temperature of 50°C. Upon cooling of the gas is condensed to 90% of the formaldehyde in the amount of 2250 kg/h Simultaneously condense 100 kg/h of methanol and 2150 kg/h of water, forming the mixture of formalin composition (wt.%): formaldehyde - 50, methanol - 2,2, water - 47,8, in which the number of 4500 kg/h is withdrawn from the process as a separate product.

Neko is dancerama part of the contact of the gases, containing in the saturation state at a temperature of 50°With 250 kg/h formaldehyde, 50 kg/h of methanol and 410 kg/h of water entering through chemisorption. At a temperature of 65°in alkaline medium at pH 7.0 gases in contact with the urea with the formation of urea-formaldehyde concentrate containing the basic substance (in terms of formaldehyde and urea) 80%. On stage chemisorption serves 111 kg/h of urea in the form of a 50% aqueous solution. The amount of urea-formaldehyde concentrate obtained in the process is 451 kg/h While the molar ratio of formaldehyde and urea in the urea-formaldehyde concentrate is 4.5:1.

Example 2. Contact gases from the reactor for the dehydrogenation of methanol on tregenna silver catalyst in the same amount and composition as in example 1, proceed to the stage of cooling below the dew point (for a given composition - 83° (C) to a temperature of 80°C. Upon cooling of the gas condenses 23% of formaldehyde in the number of 575 kg/h Simultaneously condense 15 kg/h of methanol and 276 kg/h of water, forming the mixture of formalin composition (wt.%): formaldehyde - 66,4, methanol and 1.7, water - 31,9, in which the number of 866 kg/h is withdrawn from the process as a separate product.

Non-condensable part of the contact containing gas in the saturation state at a temperature of 80°From 1925 kg/h forms is legido, 135 kg/h of methanol and 2284 kg/h of water entering the stage chemisorption, where the temperature is 65°in alkaline medium at pH 7.0 in contact with the urea with the formation of urea-formaldehyde concentrate containing the basic substance (in terms of formaldehyde and urea) 80%. On stage chemisorption serves 740 kg/h of urea in the form of a 50% aqueous solution. The amount of urea-formaldehyde concentrate is 3331 kg/h While the molar ratio of formaldehyde and urea in the urea-formaldehyde concentrate is 5.2:1.

Example 3. Contact gases from the reactor for the dehydrogenation of methanol on tregenna silver catalyst in the same amount and composition as in example 1 is directed to cooling below the dew point (for a given composition - 83° (C) to a temperature of 75°C. Upon cooling of the gas is condensed to 50% of the formaldehyde in the amount of 1250 kg/h Simultaneously condense 18 kg/h of methanol and 887 kg/h of water, forming the mixture of formalin composition (wt.%): formaldehyde - 58, methanol 0.8, water - 41,2, in which the number 2155 kg/h is withdrawn from the process as a separate product.

Non-condensable part of the contact containing gas in the saturation state at a temperature of 75°1250 kg/h formaldehyde, 132 kg/h of methanol and 1673 kg/h of water entering through chemisorption. At a temperature of 65°is in a weak alkaline medium at pH 7.0 gases in contact with the urea with the formation of urea-formaldehyde concentrate containing the basic substance (in terms of formaldehyde and urea) 80%. On stage chemisorption serves 555 kg/h of urea in the form of a 50% aqueous solution. When the molar ratio of formaldehyde and urea in the urea-formaldehyde concentrate is equal to 4.5:1. The amount of urea-formaldehyde concentrate is 2256 kg/h

Example 4. Contact gases from the reactor for the dehydrogenation of methanol on tregenna silver catalyst in the same amount and composition as in example 1, proceed to the stage of cooling below the dew point (for a given composition - 83° (C) to a temperature of 75°C. Upon cooling of the gas is condensed to 50% of the formaldehyde in the amount of 1250 kg/h Simultaneously condense 18 kg/h of methanol and 887 kg/h of water, forming the mixture of formalin composition (wt.%): formaldehyde - 58, methanol 0.8, water - 41,2, in which the number 2155 kg/h is withdrawn from the process as a separate product.

Non-condensable part of the contact containing gas in the saturation state at a temperature of 75°1250 kg/h formaldehyde, 132 kg/h of methanol and 1673 kg/h of water entering through chemisorption. At a temperature of 65°in alkaline medium at pH 7.0 gases in contact with the urea with the formation of urea-formaldehyde concentrate containing the basic substance (in terms of formaldehyde and urea) 80%. On stage chemisorption serves 480 kg/h of urea in the form of a 50% aqueous solution. The number of the received urea-formaldehyde concentrate is 2162 kg/H. When the molar ratio of formaldehyde and urea in the urea-formaldehyde concentrate equal to 5.2:1.

In the prototype in the process of chemisorption receive intermediate - preconcentrate low molar ratio of formaldehyde:urea (1.9 to 4.0)is:1, i.e. with reduced formaldehyde content, and then missing formaldehyde is injected in the form of a concentrated solution of formalin, artificially bringing the ratio to the desired (4,5-5,2):1. When conducting chemisorption with the lack of formaldehyde formed molecules methylalkanes with a different structure than in the case of an excess of formaldehyde. Moreover, the molecular structure is not corrected by artificial increase in the ratio of formaldehyde:urea to the desired mixing with concentrated formalin. Therefore, the chemical properties of produced the prototype of urea-formaldehyde concentrate does not meet the requirements of the quality used in the manufacture based resins.

From the presented examples show that the method of urea-formaldehyde concentrate is obtained under optimal conditions chemisorption immediately with the required ratio of formaldehyde:urea, equal (4,5:5,2):1, and with the desired chemical properties.

In the invention by introducing a single stage cooling contact of the gases leaving after catalytic digid the financing of methanol, simplified the whole process scheme in General, and after this stage in optimal conditions to get the final products - urea-formaldehyde concentrate and formalin, quality and composition of which depend only on the mode of conducting the process at these stages.

Simplification of the technological scheme is achieved by eliminating intermediate stages of collection intermediates, their mutual dosages, mixing, adjusting the composition and complex analytical system of mutual control, which are characteristic of the prototype.

Method for continuous receipt of formaldehyde and urea-formaldehyde concentrate, including catalytic dehydrogenation of methanol with education formaldehydefree contact of gases, of which there are part of formaldehyde in the form of formalin, the supply contact of the gases on the chemisorption of formaldehyde in an aqueous solution of urea, obtaining formaldehyde concentrate with the calculated molar ratio of formaldehyde and urea (4,5-5,2):1, characterized in that the selection of the formaldehyde from the contact of the gases in the form of formalin provide contact cooling gases dehydrogenation of methanol below the dew point temperature to a temperature of 50-80°formed during the cooling of the condensate away in the form of formalin, and the chemisorption serves the remaining stake is akt gases.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to the method for producing the triaminotoluolphosphatecarbamidoformaldehide resin. Such resin can be used for producing the fireproof coating of the construction materials and constructions. The method for producing the triaminotoluolphosphatecarbamidoformaldehide resin is described and consists in the triaminotoluolphosphate interaction with carbamide, diethanolamine and formaldehyde at the molar ratio 1:1-4:0.2-0.8:5-12, correspondingly. To obtain the homogenous resin solution, the reaction temperature is increased from 20°C to 80°C. Also, the application of resin as a fireproof coating is described.

EFFECT: resin is able to foam and produce the porous protective layer with low thermal conductivity.

3 cl, 3 ex

FIELD: polymer production.

SUBSTANCE: invention relates to technology of producing urea-formaldehyde resins appropriate for manufacturing wood particle boards, fiberboards, plywood, and joiner's building parts, and also for joining furniture parts. Urea-formaldehyde resin production process comprises multistage condensation of urea with urea-formaldehyde concentrate in aqueous solution in a medium having variable acidity at specified temperature conditions. Low-alkalinity condensation is carried out at formaldehyde-to-urea molar ratio (1.8-2.2):1 at 20-95°C and pH 7.3-8.6. Condensation solution is then kept for 10-20 min at 99-95°C and acidified to pH 5.0-5.6. Low-alkalinity condensation product is cooled to 83-87°C and acid condensation is carried out to simultaneously achieve relative viscosity of reaction mixture 90 to 189 sec (VZ-3 viscosimeter) and limiting miscibility between 1:6 and 1:3. Formaldehyde-to-urea molar ratio after loading of the second additional urea portion is (1,2-1,45):1 and final molar ratio after loading of the last portion of urea is (1.1-1,3):1. Finished resin is cooled and packaged. Above-mentioned urea-formaldehyde concentrate is a low-methanolic urea-formaldehyde concentrate containing no more than 0.3 wt % methanol. Advantage of the present process consists in that it allows ensuring controllability of the process, reproducibility of technical characteristics of resin, achievement of specified limiting miscibility value, reduced methanol emission, improved sanitary conditions during properties and processing of resin, and production of resin meeting requirements of existing standards.

EFFECT: enhanced process efficiency and reduced production expenses due to use of inexpensive low-methanolic urea-formaldehyde concentrate.

2 cl, 3 tbl, 10 ex

FIELD: polymer production.

SUBSTANCE: invention, in particular, relates to production of urea-formaldehyde resins widely used in wood-working industry. Process according to invention is implemented via condensation of urea-formaldehyde concentrate with urea on heating first in neutral or low-alkaline medium and then in acidic medium in presence of catalytic additive composed of formaldehyde, sodium hydroxide, and sulfuric acid at molar ratio 1.0:(0.4-0.5):(0.1-0.3), respectively, followed by co-condensation of formed product with additional amount of urea in neutral or low-alkaline medium at initial and final urea-to-formaldehyde molar ratios 1.0:(1.9-2.1) and 1.0:(1.1-1.6), respectively. Action of impurities in urea-formaldehyde concentrate and urea is neutralized with sodium hydroxide solution until pH of mixture 6.0-8.0 is attained. Stabilization of pH of reaction mixture is achieved by using catalytic additive in amount 0.1-0.3% of the weight of initial formaldehyde in urea-formaldehyde concentrate.

EFFECT: simplified technology with high principal characteristics of resins preserved.

3 cl, 1 tbl, 4 ex

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: chemical technology.

SUBSTANCE: invention relates to producing urea-formaldehyde resins. Invention describes a method for preparing urea-formaldehyde resins involving condensation of urea-formaldehyde concentrate with carbamide. Condensation is carried out at the initial mole ratio formaldehyde to carbamide = (1.72-2.3):1 at temperature 80-95°C and medium pH 6-9 followed by change of pH medium to 3.5-5.5 with adduct based on a mixture of aliphatic aminoalcohols with inorganic and/or organic acids or their anhydrides no containing chloride ions or a mixture of aliphatic and heterocyclic aminoalcohols with inorganic and/or organic acids or their anhydrides no containing chloride ions, at their mass ratio = (1.0-3.0):1.0 in the amount 0.1-3.0% of urea-formaldehyde concentrate mass followed by carrying out the condensation reaction with additional amount of carbamide to achievement of viscosity value 30-80 s and the following condensation of additional amount of carbamide wherein the final mole ratio of formaldehyde to carbamide = (0.9-1.76):1 and cooling the resin. Invention provides the development of operated technology for synthesis of urea-formaldehyde resins with required properties and, first of all, the low content of formaldehyde after their hardening. Invention can be used in manufacturing urea-formaldehyde resins used as binding agents for making splint-slab and wood-fiber slabs, veneer, adhesives for gluing wood, binding agent components used in making heat-insulating materials and others.

EFFECT: improved method of synthesis of resins.

3 tbl, 1 dwg, 12 ex

FIELD: chemical industry; construction materials industry; methods of production of the carbamide-formaldehyde resin.

SUBSTANCE: the invention is pertaining to the methods of production of the water soluble carbamide-formaldehyde resins applied as binding agents and adhesives used for the timber bonding in production of the wood chipboards, the wood-fiber boards, other similar materials and the heat-insulating materials. The method of production of carbamide-formaldehyde resin provides for condensation of the amino-formaldehyde concentrate representing the aqueous composition, containing of 41.5-60.0 mass % of the formaldehyde and of 20.5-25.0 mass % of the carbamide with the viscosity controller , I the capacity of which use 37 % formalin introduced in one step together with the carbamide-formaldehyde concentrate at the stage of the alkaline condensation before the loading of the first batch of the carbamide and also at presence of 0.02-0.20 mass % of the first batch of the of the additive agent in terms of 100 mass % of the carbamide-formaldehyde concentrate and the first batch of carbamide at the heating in the water solution with the variable acidity and the following additional condensation of the formed product with the additional amount of carbamide and introduction of the second batch of the buffer additive component at the initial and the final molar ratio of carbamide and formaldehyde as 1:(1.9-2.1) and 1:(1.02-1.7) accordingly and the refrigerations of the ready resin. The technical result of the invention is optimization of the conditions for production of the low-molar carbamide-formaldehyde resins with the heightened conditional viscosity and preservation at the high level of the other quality factors.

EFFECT: the invention ensures optimization of the conditions for production of the low-molar carbamide-formaldehyde resins with the heightened conditional viscosity and preservation at the high level of the other quality factors.

2 ex, 1 tbl

FIELD: polymer production.

SUBSTANCE: invention, in particular, relates to binders used for manufacturing molding blends employed for molding profiled items from light alloys. Preparation of urea-formaldehyde binder comprises urea/formaldehyde condensation to achieve refractory index 1.4055-1.4072. Condensation is carried out at initial urea-to-formaldehyde molar ratio 1:(1.95-2.18), pH of mixture from 8 to (4.7-4.1) until viscosity of resin (using viscosimeter VS-4, nozzle 4 mm) 15.5-26.0 s, after which mixture is neutralized to pH 7.0-8.5, water is distilled off from boiling reaction mixture until refractory index achieves 1.4220-1.4230 followed by addition of polyvinyl alcohol solution at a rate of 1.2% solid substance based on initial weight of urea. Reaction mixture is then cooled and two further portions of urea are added to achieve final urea-to-formaldehyde molar ratio 1:(1.40-1.43). When second portion of urea is being charged, sodium decahydrotetraborate is simultaneously added in amount 0.35-0.7% based on the total weight of urea and then first and second post-condensation steps are conducted, each step being followed by ageing for 30-50 min.

EFFECT: reduced toxicity of resin, achieved controlled viscosity and gelation time, improved water resistance, and prolonged shelf time.

3 cl, 1 tbl, 4 ex

FIELD: polymer production.

SUBSTANCE: preparation of urea-formaldehyde resin comprises urea/formaldehyde condensation carried out in presence of ammonia at pH varying from 7.1-7.15 to 5.1-5.3 at 88-104°C, atmosphere pressure, and urea/formaldehyde/ammonia molar ratio 1:(2.0-2.2):(0.1-0.13) until viscosity (using viscosimeter VS-4) achieves 15.5-26.0 s, after which mixture is subjected to post-condensation at 77-58°C with additional urea to achieve final urea-to-formaldehyde molar ratio 1:(1.9-2.0). Reaction mixture is the given additional amount of ammonia and held at 62-38°C for 20-30 min until final urea-to-ammonia ratio 1:(0.11-0.19).

EFFECT: enabled production of low-toxicity, freely flowing binder capable of being hardened at ambient temperature for required hardening time and providing high strength to reinforced ground, reduced production expenses, and simplified equipment.

3 cl, 1 tbl, 4 ex

FIELD: polymer production.

SUBSTANCE: invention relates to production of urea-formaldehyde resins used as binders in manufacture of wood particle boards, wooden fiberboards, plywood, wood adhesives, and in other industrial fields. Invention provides a method for producing uron-containing urea-formaldehyde resins via consecutive condensation of urea-formaldehyde concentrate with solid urea first at formaldehyde-to-urea molar ratio (5.2-3.3):1, pH below or equal to 3, and temperature above or equal to 80°C and then at molar ratio (2.5-2.65):1 at pH 7.0-9.0 and 20-70°C, urea being added first in amount providing formaldehyde-to-urea molar ratio in resin (2.10-2.40):1 and then in amount providing above ratio equal to (1.50-2.09):1.

EFFECT: simplified resin production technology at the same high physicochemical properties of products based thereon and reduced toxicity of products.

3 tbl, 4 ex

FIELD: polymer production.

SUBSTANCE: production of urea-formaldehyde filler, useful as synthetic white filler in manufacture of polymers, paper, and varnish-and-paint materials, is accomplished by interaction of urea with urea-formaldehyde concentrate modified in synthesis stage with 1 to 20% of uranium derivatives and containing 54.5-59.5% formaldehyde, 21.0-24.5% urea, the rest water. Synthesis is carried out in aqueous medium in presence of phosphoric acid at elevated temperature, after which reaction mixture is neutralized with chalk/aminoalcohol/aqueous ammonia mixture [(1-4):(1-4):(1-5)]. Aminoalcohol is a product composed of 30-70% monoethanolamine, 10-50% mixture of 1-(2-hydroxyethyl)imidazol-2-ine and 1-(2-hydroxyethyl)ethylenediamine, and water (no more than 20%).

EFFECT: enhanced process efficiency and lowered oil absorption.

1 tbl, 2 ex

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

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 invention relates to a continuous method of obtaining aqueous solutions of formaldehyde, in particular solutions having a concentration in the range from 53 to 57 wt.%, the method includes the following stages:

(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: chemical technology.

SUBSTANCE: invention relates to a method for continuous synthesis of glyoxal-containing products of the desired concentration in a single-step technological cycle. Method involves vapor-phase catalytic process of partial oxidative dehydrogenation of ethylene glycol with oxygen diluted with steam and nitrogen in the mole ratio from 1/6.5 to 1/13.0 at temperature 400-700°C on carrier Ag-contacts and massive Ag-catalysts made of materials of electrolytic origin of particles size 0.1-4.0 mm. Then the process involves continuous the vat-less separation of vapor-gaseous oxidate for liquid fractions and gaseous phase wherein prepared aqueous aldehyde solutions contain 4-40% of glyoxal, 6.2% of glycolic aldehyde, not above, 4.6% of formaldehyde, not above, 4.0% of ethylene glycol, not above, at the total acidity index 2%. The end product comprises 39.8% of glyoxal, 5.5% of glycolic aldehyde and 0.4% of formaldehyde. The process of continuous the vat-less separation of synthesis products for glyoxal-containing liquid fractions and depleted gaseous phase is carried out continuously in the range of temperature 10-400°C as result of subcontact cooling in combination with three-step combined condensation of components of vapor-gaseous oxidate in a cascade block-unit in fractional isolation of liquid and gaseous products of synthesis, and in regulation of heat regimen of the combined condensation and change of the ratio of liquid fractions.

EFFECT: improved method of synthesis.

1 dwg, 13 ex

FIELD: organic chemistry, fuel production.

SUBSTANCE: claimed method includes feeding of heated hydrocarbon-containing and oxygen-containing gas in reaction unit, vapor phase oxidation of hydrocarbon-containing gas at 250-450°C and pressure of 2.0-10 MPa under near isothermal conditions; cooling of reaction mixture in heat exchangers, separation of gas and liquid phases of reaction mixture. separation of obtained methanol solution of formaldehyde, C2-C4-alcohols and methanol, methanol and gas phase after separation into reactors; catalytic methanol conversion on zeolite catalyst at 350-450°C and pressure of 3-8 MPa; cooling of produced reaction mixture in heat exchangers; separation of gas and liquid phases of reaction mixture; separation of aqueous fraction and synthetic diesel fuel liquid fractions, including fraction of liquid hydrocarbons, corresponding to motor gasoline having octane number of at least 92.

EFFECT: products of high quality; simplified technology; decreased energy consumption.

5 cl, 1 tbl

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: organic chemistry, in particular formaldehyde production.

SUBSTANCE: claimed method includes oxidation of hydrocarbon-containing gas with oxygen-containing gas at elevated temperature and pressure followed by reaction mixture cooling and separation of target liquid product. As hydrocarbon-containing gas ethane-containing gas is used, including natural and associated gases containing not less than 10 % of ethane. Ethane-containing gas preliminary pressed up to 2-5 MPa and heated up to 280-450°C, and oxygen-containing gas, preliminary pressed up to pressure of ethane-containing gas or more are separately fed into blenders of arranged in tandem reaction zones up to oxygen content of 2-10 vol.%. Reaction mixture is continuously cooled through wall either directly in oxidation process or before feeding thereof in next reaction zone to temperature not more than 450°C. As oxygen-containing gas air, oxygen or oxygen-enriched air are used.

EFFECT: increased formaldehyde yield, simplified process, decreased energy consumption.

2 cl, 4 ex, 1 tbl, 1 dwg

FIELD: industrial organic synthesis and chemical engineering .

SUBSTANCE: invention relates to a process of producing liquid oxygenates, including methanol, C2-C4-alcohols, formaldehyde, lower organic acids, or mixtures thereof, and to installation for implementation the process. Process comprises successively supplying natural gas from complex gas preparation plant to a series of "gas-gas" heat exchangers and into annular space of at least one tubular reaction zone of reactor, wherein natural gas is heated to temperature of the beginning of reaction, whereupon heated gas is passed to the entry of the tubular reaction zone mixer, into which compressed air or oxygen is also injected to provide gas-phase oxidation in reaction zone of reactor. Resulting reaction mixture is discharged from reactor into a series of "gas-liquid" and "gas-gas" heat exchangers, wherein reaction mixture is cooled to ambient temperature and sent to separator, wherefrom liquid phase is passed through lower carboxylic acid recovery vessel to the system of rectification columns to isolate the rest of mixture components, whereas leaving gas is recycled to complex gas preparation plant. More specifically, oxidation is carried out within temperature range 240 to 450°C and pressure from 2 to 10 MPa at residence time of reaction mixture in reactor 2-6 sec and oxidant concentration 2 to 15 wt %. In reactor having mixers hollow and at least one tubular reaction zones, required temperature is maintained constant throughout all length of tubular reaction zone and at entries for compressed air or oxygen in mixers of each of tubular reaction zones and hollow reaction zone. Liquid oxygenate production plant is composed of aforesaid complex gas preparation plant, a series of "gas-gas" heat exchanger to heat natural gas, reactor, a series of "gas-liquid" and "gas-gas" heat exchangers to cool reaction mixture obtained in reactor, gas-liquid separator, lower carboxylic acid recovery vessel, and system of rectification columns to isolate the rest of products.

EFFECT: enabled implementation of the process directly near gas and gas condensate deposits, increased conversion of methane per one passage through reactor, and increased yield of oxygenates due to improved design of plant.

6 cl, 1 dwg, 1 tbl

FIELD: industrial organic synthesis.

SUBSTANCE: formaldehyde is produced via oxidative dehydrogenation of methanol with air oxygen at high temperature on silver-containing in fixed-bed reactor enclosing gas stream distributor followed by absorption of resultant reaction gases to form methanolic formalin, which is further rectified. Gas stream distributor utilized is inert filling composed of geometrically shaped members 3-10 mm in diameter placed on grid mounted upstream of catalyst in the form of a bed 50 to 500 mm thick.

EFFECT: increased conversion and selectivity of process.

1 dwg, 4 ex

The invention relates to the chemical industry, in particular to methods of regeneration of silver catalysts for the preparation of formaldehyde from methanol
Up!