CN114644556A - Device and process method for preparing propionate - Google Patents
Device and process method for preparing propionate Download PDFInfo
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- CN114644556A CN114644556A CN202011519008.0A CN202011519008A CN114644556A CN 114644556 A CN114644556 A CN 114644556A CN 202011519008 A CN202011519008 A CN 202011519008A CN 114644556 A CN114644556 A CN 114644556A
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- rectifying tower
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- rectifying
- propionic acid
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- 238000000034 method Methods 0.000 title claims abstract description 61
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 title claims description 41
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 claims abstract description 269
- 235000019260 propionic acid Nutrition 0.000 claims abstract description 132
- IUVKMZGDUIUOCP-BTNSXGMBSA-N quinbolone Chemical compound O([C@H]1CC[C@H]2[C@H]3[C@@H]([C@]4(C=CC(=O)C=C4CC3)C)CC[C@@]21C)C1=CCCC1 IUVKMZGDUIUOCP-BTNSXGMBSA-N 0.000 claims abstract description 132
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 84
- 239000002994 raw material Substances 0.000 claims abstract description 77
- -1 alcohol compound Chemical class 0.000 claims abstract description 24
- 238000006243 chemical reaction Methods 0.000 claims abstract description 20
- 239000013067 intermediate product Substances 0.000 claims abstract description 11
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 135
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 90
- 239000003054 catalyst Substances 0.000 claims description 48
- 239000000463 material Substances 0.000 claims description 43
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 claims description 42
- 238000010992 reflux Methods 0.000 claims description 34
- FKRCODPIKNYEAC-UHFFFAOYSA-N ethyl propionate Chemical compound CCOC(=O)CC FKRCODPIKNYEAC-UHFFFAOYSA-N 0.000 claims description 30
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 claims description 29
- 238000000926 separation method Methods 0.000 claims description 27
- 239000000203 mixture Substances 0.000 claims description 26
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 21
- 150000001298 alcohols Chemical class 0.000 claims description 20
- 239000002808 molecular sieve Substances 0.000 claims description 15
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims description 15
- 239000003795 chemical substances by application Substances 0.000 claims description 12
- 239000002815 homogeneous catalyst Substances 0.000 claims description 10
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 9
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 8
- 230000018044 dehydration Effects 0.000 claims description 7
- 238000006297 dehydration reaction Methods 0.000 claims description 7
- 239000002638 heterogeneous catalyst Substances 0.000 claims description 7
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 6
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 claims description 6
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 claims description 6
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 5
- 238000004064 recycling Methods 0.000 claims description 4
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 claims description 3
- 238000011049 filling Methods 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 238000011112 process operation Methods 0.000 claims description 2
- 239000012071 phase Substances 0.000 abstract description 21
- 239000007791 liquid phase Substances 0.000 abstract description 11
- JOXIMZWYDAKGHI-UHFFFAOYSA-N toluene-4-sulfonic acid Chemical compound CC1=CC=C(S(O)(=O)=O)C=C1 JOXIMZWYDAKGHI-UHFFFAOYSA-N 0.000 description 24
- 238000012856 packing Methods 0.000 description 20
- 239000000047 product Substances 0.000 description 20
- RJUFJBKOKNCXHH-UHFFFAOYSA-N Methyl propionate Chemical compound CCC(=O)OC RJUFJBKOKNCXHH-UHFFFAOYSA-N 0.000 description 19
- 229940017219 methyl propionate Drugs 0.000 description 19
- 239000000945 filler Substances 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- UHOPWFKONJYLCF-UHFFFAOYSA-N 2-(2-sulfanylethyl)isoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(CCS)C(=O)C2=C1 UHOPWFKONJYLCF-UHFFFAOYSA-N 0.000 description 9
- 239000012528 membrane Substances 0.000 description 8
- 239000011347 resin Substances 0.000 description 8
- 229920005989 resin Polymers 0.000 description 8
- 239000007788 liquid Substances 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 5
- 238000002309 gasification Methods 0.000 description 4
- 239000000284 extract Substances 0.000 description 3
- 238000000066 reactive distillation Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 125000000542 sulfonic acid group Chemical group 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 125000003158 alcohol group Chemical group 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 238000010533 azeotropic distillation Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910001628 calcium chloride Inorganic materials 0.000 description 2
- 239000001110 calcium chloride Substances 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 230000032050 esterification Effects 0.000 description 2
- 238000005886 esterification reaction Methods 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- HFZLSTDPRQSZCQ-UHFFFAOYSA-N 1-pyrrolidin-3-ylpyrrolidine Chemical compound C1CCCN1C1CNCC1 HFZLSTDPRQSZCQ-UHFFFAOYSA-N 0.000 description 1
- 244000099147 Ananas comosus Species 0.000 description 1
- 235000007119 Ananas comosus Nutrition 0.000 description 1
- XINCECQTMHSORG-UHFFFAOYSA-N Isoamyl isovalerate Chemical compound CC(C)CCOC(=O)CC(C)C XINCECQTMHSORG-UHFFFAOYSA-N 0.000 description 1
- 240000008790 Musa x paradisiaca Species 0.000 description 1
- 235000018290 Musa x paradisiaca Nutrition 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 235000014121 butter Nutrition 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000000025 natural resin Substances 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 239000011949 solid catalyst Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 235000013599 spices Nutrition 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The application discloses device I, device I includes: a first rectification column; a propionic acid inlet is formed in the top of the first rectifying tower; an alcohol compound inlet is formed in the bottom of the first rectifying tower; and an intermediate product gas outlet is formed in the top of the first rectifying tower. According to the method, the liquid-phase propionic acid moves from the top of the rectifying tower to the bottom of the rectifying tower, the alcohol raw material flows from the bottom of the rectifying tower to the top of the rectifying tower in a gas phase state, the alcohol raw material and the rectifying tower are in countercurrent contact and react, the closer to the top of the rectifying tower, the higher the propionic acid content is, the lower the alcohol content is, and the influence of multi-component azeotropy is eliminated by virtue of the reaction.
Description
Technical Field
The application relates to a device and a process method for preparing propionate, belonging to the technical field of propionate.
Background
The propionate is low in toxicity and can be applied to solvents of natural or synthetic resins; can be used as spice for blending apple essence, banana essence, plum essence, pineapple essence, butter, western wine and other edible essence, and can also be used as high-grade daily-use cosmetic essence; the ethyl propionate and the propyl propionate can promote the low-temperature performance of the lithium ion battery, improve the compatibility of the electrolyte with the anode material and the cathode graphite material, reduce the viscosity and the eutectic point of the electrolyte system, and are beneficial to the migration of lithium ions.
Taking ethyl propionate as an example, the traditional process adopts an esterification method, concentrated sulfuric acid, p-toluenesulfonic acid or sulfonic acid resin is used as a catalyst, and benzene, toluene or cyclohexane is used as an intermittent reaction process of a water-carrying agent. The water generated after the esterification of the propionic acid and the ethanol is separated out of the reaction system by the water-carrying agent, but because the azeotropic point of the ethanol and the water-carrying agent is lower, the ethanol, the water and the water at the top of the tower generally comprise 30% of ethanol, 10% of water and 60% of the water-carrying agent by mass, so that a large amount of ethanol is carried out of the reaction system, latent heat of a large amount of ethanol and the water-carrying agent is wasted in the rectification process, and the energy consumption is high; the reaction raw material ethanol is excessive in quantity, the conversion rate of the propionic acid is higher than 90% as much as possible, and the ethanol separated from the tower top can only be recovered by the azeotropic composition of 95% ethanol and 5% water; about 2% of propionic acid, 5% of ethanol, 2% of water and about 91% of ethyl propionate are remained in the tower bottom product, and the unreacted propionic acid and the catalyst are removed by alkali washing and then are rectified and separated, so that the yield of the propionic acid is low and is only about 95%, and the raw material waste is caused.
Disclosure of Invention
According to one aspect of the application, a device I is provided, wherein liquid phase propionic acid moves from the top of a rectifying tower to the bottom of the rectifying tower, an alcohol raw material flows from the bottom of the rectifying tower to the top of the rectifying tower in a gas phase state, the alcohol raw material and the rectifying tower are in countercurrent contact and react, the closer to the top of the rectifying tower, the higher the propionic acid content is, the lower the alcohol content is, and the influence of multi-component azeotropy is eliminated by virtue of the reaction.
According to a first aspect of the present application, there is provided an apparatus I, comprising: a first rectification column; a propionic acid inlet is formed in the top of the first rectifying tower; an alcohol compound inlet is formed in the bottom of the first rectifying tower;
and an intermediate product gas outlet is formed in the top of the first rectifying tower.
Optionally, a propionic acid outlet is further arranged at the bottom of the first rectifying tower;
the propionic acid outlet is connected with the propionic acid inlet at the top of the first rectifying tower.
Optionally, the propionic acid inlet is positioned at a full tower height of 1/6-1/2 away from the top of the first rectifying tower;
the height from the alcohol compound inlet to the tower kettle of the first rectifying tower is 0-1/2 of the total tower height;
the propionic acid inlet is higher than the alcohol compound inlet.
Optionally, the propionic acid inlet is positioned at a full tower height of 1/5-1/3 away from the top of the first rectifying tower;
the height of the alcohol compound inlet from the tower bottom of the first rectifying tower is 1/10-1/4 of the total tower height.
Optionally, the number of plates of the first rectifying tower is 40-60.
Optionally, the device I further comprises a knockout drum and a second rectifying tower;
the inlet end of the water diversion tank is connected with the top of the first rectifying tower, and the outlet end of the water diversion tank is connected with the top of the second rectifying tower;
preferably, the number of plates of the second rectifying column is 30 to 80.
Preferably, the water separation tank comprises at least one of a molecular sieve and anhydrous calcium chloride.
Optionally, the function of the water separation tank is as follows: the anhydrous calcium chloride chemisorbs water in the propionate-alcohol-water system, and then uses a 4A or 5A molecular sieve to adsorb a small amount of residual water, so that the water content of the system is controlled below 500ppm, preferably below 100 ppm.
Optionally, the water separation tank contains a molecular sieve inorganic membrane, so that the water content of the system can be controlled below 500ppm, preferably below 100 ppm.
Optionally, the second rectification column top is connected to the first rectification column bottom such that the second rectification column top stream passes to the first rectification column bottom;
and a propionate outlet is arranged at the tower kettle of the second rectifying tower.
Optionally, the apparatus I further comprises a third rectification column; the first rectifying tower kettle is connected with the top of the third rectifying tower, so that the material flow of the third rectifying tower kettle is introduced into the third rectifying tower;
the third rectifying tower kettle is connected with the top of the first rectifying tower, so that the material flow of the third rectifying tower kettle is introduced into the first rectifying tower;
preferably, the number of plates of the third rectifying column is 30 to 60.
According to a second aspect of the present application, a process I for the preparation of propanoates is provided, carried out using the above-described apparatus I.
Optionally, the following process steps are included:
(1) introducing a raw material I containing propionic acid from the top of a first rectifying tower, introducing a raw material II containing alcohol compounds from the bottom of the first rectifying tower, reacting, and obtaining the intermediate product gas containing propionate at the top of the first rectifying tower;
filling a catalyst I in the first rectifying tower or containing the catalyst I in a raw material I containing propionic acid;
the molar ratio of the propionic acid to the alcohol compound is 2: 1-10: 1.
optionally, the raw materials are propionic acid (with purity of more than 99%) and various alcohols (with purity of more than 99.5%) at a feed molar ratio of 2:1 to 10:1, preferably 4:1 to 6: 1.
The alcohol compound is selected from alcohol normal isomers and isomers such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and tert-butanol.
Optionally, process I provided herein comprises a first rectification column, a knock-out drum, and a second rectification column.
Optionally, the step (1) comprises: and the raw material I and the raw material II react in the first rectifying tower to generate a gas-phase azeotrope containing propionate, the gas-phase azeotrope flows towards the top of the first rectifying tower and continuously reacts with the raw material I introduced from the top of the first rectifying tower to generate intermediate product gas containing propionate.
According to the process method I provided by the application, a propionate-alcohol system subjected to water separation by the water separation tank is separated by the second rectifying tower, light components at the top of the second rectifying tower are recycled to the alcohol raw material, and a propionate product is extracted from the bottom of the second rectifying tower, wherein the purity of the propionate product is more than 99%.
Optionally, the intermediate product gas also contains water and alcohol compounds;
the content of the alcohol compound in the intermediate product gas is 0-3 wt%.
Optionally, in the raw material I containing propionic acid, the mass content of the catalyst I is 0.5-3%.
Optionally, the alcohol compound is selected from at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and tert-butanol.
Optionally, the catalyst I is selected from any one of homogeneous catalysts, heterogeneous catalysts.
Optionally, the homogeneous catalyst is selected from any one of concentrated sulfuric acid and p-toluenesulfonic acid;
the heterogeneous catalyst is selected from sulfonic acid resins.
Optionally, the process operating conditions of the first rectification column are: the temperature of the tower top is 55-110 ℃; the temperature of the tower kettle is 135-150 ℃; the reflux ratio of the tower top is 1:1-2: 1.
Optionally, the propionic acid obtained from the bottom of the first rectifying tower is recycled to the top of the first rectifying tower for use.
Optionally, the following process steps are also included:
(2) introducing a material flow containing propionate obtained at the top of the first rectifying tower into a water separation tank;
(3) introducing a material flow obtained after dehydration in the water separation tank into the top of a second rectifying tower, circulating the material flow extracted from the top of the second rectifying tower to the tower kettle of the first rectifying tower, and obtaining the propionate in the tower kettle of the second rectifying tower;
the water separation tank contains at least one of anhydrous calcium chloride and a molecular sieve.
Optionally, the process operating conditions of the second rectification column are: the temperature of the tower top is 50-80 ℃; the temperature of the tower kettle is 80-120 ℃; the reflux ratio at the top of the tower is 1:1-2: 1.
Optionally, the water content of the stream obtained after dehydration in the water separation tank is less than or equal to 500 ppm.
Optionally, the following process steps are also included:
(4) introducing the material flow obtained at the bottom of the first rectifying tower into the top of a third rectifying tower, introducing the material flow at the bottom of the third rectifying tower into the top of the first rectifying tower, and returning the material flow at the top of the third rectifying tower to the top of the third rectifying tower;
a water carrying agent is filled in the third rectifying tower;
preferably, the water-carrying agent is selected from any one of toluene, benzene, toluene and cyclohexane.
Optionally, the process operating conditions of the third rectification column are: the temperature of the tower top is 80-100 ℃; the temperature of the tower kettle is 90-130 ℃; the reflux ratio of the tower top is 1:1-2: 1. Alternatively, the process for the preparation of propanoates, process I, comprises the process steps of:
(1) raw material propionic acid carrying homogeneous catalyst is fed from the top of a first rectifying tower, and raw material containing alcohol compounds is fed from the bottom of the first rectifying tower; or a sulfonic acid resin catalyst is directly filled into the first rectifying tower, and the propionic acid raw material does not need to carry an additional homogeneous catalyst;
(2) the flow mode of the propionic acid in the first rectifying tower is that the propionic acid flows from the top of the first rectifying tower to the bottom of the first rectifying tower in a liquid phase; various alcohol compounds flow from the bottom of the first rectifying tower to the top of the first rectifying tower in a gas phase state; the gas-liquid phases are contacted in a first rectifying tower;
(3) the generated propionate, water and unreacted alcohol form binary or ternary azeotrope, and the binary or ternary azeotrope continuously moves to the top of the first rectifying tower in a gas phase;
(4) the closer to the top of the first rectifying tower, the higher the propionic acid content is, and the propionic acid continues to react with various alcohols; the tower top produced substance of the first rectifying tower is propionate and water, the alcohol content is lower than 3 percent, and the alcohol raw material is consumed by means of reactive distillation and a large amount of excess propionic acid;
(5) dehydrating the extract at the top of the first rectifying tower by using calcium chloride, and then dehydrating by using a 4A or 5A molecular sieve; or dehydrating through an inorganic molecular sieve membrane;
(6) the propionic acid in the tower kettle of the first rectifying tower is recycled to the reaction raw material;
(7) the dehydrated material flow (propionate product with the content higher than 95 percent and a small amount of corresponding alcohol) enters a second rectifying tower for product separation;
(9) qualified propionate products are extracted from the bottom of the second rectifying tower; and the propionate and the alcohol at the top of the second rectifying tower are recycled to the reaction raw materials.
According to the process method I provided by the application, raw material propionic acid is fed from the lower part of the top of a first rectifying tower, various alcohol raw materials are fed from the bottom of the first rectifying tower, the raw materials and the alcohol raw materials are in reverse contact in the first rectifying tower and react under the action of a catalyst, excessive propionic acid on the top of the first rectifying tower continuously consumes the alcohol raw materials, and a binary or ternary azeotropic system of propionate-alcohol-water is broken; the composition of the top of the first rectifying tower is about more than 80% of propionate, less than 3% of alcohol and about 15% of water, and the propionate, the alcohol and the water are dehydrated and then enter the second rectifying tower for separation; the propionic acid in the tower kettle of the first rectifying tower circulates to a material inlet from the tower top of the first rectifying tower; and an azeotrope of alcohol and propionate extracted from the top of the second rectifying tower is recycled to the bottom of the first rectifying tower, and a qualified propionate product is extracted from the bottom of the second rectifying tower.
According to a third aspect of the present application, there is provided an apparatus II, comprising: a first rectifying tower and a second rectifying tower;
the top of the rectifying tower I is provided with an inlet for propionic acid and alcohol compounds;
the top of the first rectifying tower is connected with the top of the second rectifying tower, so that the material flow at the top of the first rectifying tower is introduced into the top of the second rectifying tower;
an entrainer inlet is formed in the top of the rectifying tower II; or the like, or, alternatively,
the top of the rectifying tower I is connected with the top of the rectifying tower II through a pipeline; the pipeline is provided with an entrainer inlet.
Optionally, the device II further comprises a water separator;
the inlet of the water separator is connected with the tower top of the second rectifying tower, so that the tower top material flow of the second rectifying tower is introduced into the water separator;
the outlet of the water separator is respectively connected with the propionic acid inlets at the top of the rectifying tower II and the top of the rectifying tower I;
preferably, the number of the plates of the rectifying tower I and the number of the plates of the rectifying tower II are 40-60.
Optionally, the device II further comprises a III rectifying tower;
the tower kettle of the II rectifying tower is connected with the top of the III rectifying tower, so that the tower kettle material flow of the II rectifying tower is introduced into the top of the III rectifying tower;
the tower kettle of the III rectifying tower is connected with an entrainer inlet at the top of the II rectifying tower, so that the tower kettle material flow of the III rectifying tower is introduced into the top of the II rectifying tower;
preferably, the number of the plates of the III rectifying tower is 40-60.
Optionally, the device II further comprises an IV rectifying tower;
the tower bottom of the I rectifying tower is connected with the top of the IV rectifying tower, so that the tower bottom material flow of the I rectifying tower is introduced into the top of the IV rectifying tower;
the top of the IV rectifying tower is connected with a propionic acid inlet at the top of the I rectifying tower, so that the top stream of the IV rectifying tower is introduced into the top of the I rectifying tower;
preferably, the number of plates of the IV rectifying tower is 40-60.
Optionally, the apparatus II further comprises a pre-reactor;
one end of the pre-reactor is provided with a propionic acid and alcohol compound inlet; the other end of the prereactor is connected with the top of the rectifying tower I.
According to the fourth aspect of the application, a process method II for preparing propionic ester is also provided, and is characterized by being carried out by the device II.
Optionally, the following process steps are included:
(a) introducing raw materials containing propionic acid and alcohol compounds into the top of a first rectifying tower, reacting in the first rectifying tower, mixing material flow obtained at the top of the first rectifying tower with material flow containing an entrainer, introducing the mixture into the top of a second rectifying tower, and obtaining the propionate in the bottom of the second rectifying tower;
the catalyst II is filled in the rectifying tower I or the raw material containing the propionic acid and the alcohol compound contains the catalyst II.
Optionally, the catalyst II is selected from any one of homogeneous catalysts, heterogeneous catalysts.
Preferably, the homogeneous catalyst is selected from any one of concentrated sulfuric acid and p-toluenesulfonic acid;
the heterogeneous catalyst is selected from sulfonic acid resins.
Alternatively, the molar ratio of the propionic acid to the alcohol compound is 1: 1-1: 10;
preferably, in the raw material containing propionic acid and alcohol compounds, the mass content of the catalyst II is 1-2%.
Optionally, the process operating conditions of the rectifying tower I are as follows: the temperature of the tower top is 55-110 ℃; the temperature of the tower kettle is 135-150 ℃; the reflux ratio of the tower top is 1:1-2: 1;
the process operation conditions of the rectifying tower II are as follows: the temperature of the tower top is 60-80 ℃; the temperature of the tower kettle is 80-100 ℃; the reflux ratio of the tower top is 1:1 to 2.
Optionally, in the step (a), the mass ratio of the stream obtained at the top of the I rectifying tower to the entrainer is 1: 0.5 to 2.
Optionally, the material flow obtained at the top of the rectifying tower II is subjected to standing and layering, the alcohol compound obtained after layering is recycled to the reaction raw material, and the obtained n-heptane is recycled to the top of the rectifying tower II.
Optionally, in the step (a), the raw material containing propionic acid and alcohol compounds is pre-reacted in a pre-reactor and then is introduced into the top of the I rectifying tower;
the pre-reactor is filled with the catalyst II or the raw material containing the propionic acid and the alcohol compound contains the catalyst II.
Optionally, the following process steps are also included:
(b) introducing the material flow obtained from the tower bottom of the II rectifying tower to the top of a III rectifying tower, obtaining the propionate from the tower top of the III rectifying tower, and introducing the material flow obtained from the tower bottom of the III rectifying tower to the top of the II rectifying tower;
preferably, the process operating conditions of the III rectifying tower are as follows: the temperature of the tower top is 70-90 ℃; the temperature of the tower kettle is 90-110 ℃; the reflux ratio of the tower top is 1:1-2: 1.
optionally, the following process steps are also included:
(c) introducing the material flow obtained from the tower bottom of the I rectifying tower into an IV rectifying tower, and circulating the material flow obtained from the tower top of the IV rectifying tower to the top of the I rectifying tower for recycling;
preferably, the process operating conditions of the IV rectifying tower are as follows:
the temperature of the tower top is 60-70 ℃; the temperature of the tower kettle is 99-105 ℃; the reflux ratio of the tower top is 1:1-2: 1.
the beneficial effects that this application can produce include:
1. excessive propionic acid at the top of the rectifying tower and excessive alcohol content in a ternary azeotropic system of propionate, water and alcohol are eliminated by a reaction-rectification technical means, the content of propionate can be controlled to be more than 80 percent by a single tower, and the content of alcohol is controlled to be less than 3 percent;
2. a water-carrying agent is not needed, and the content of alcohol and propionate returned by the second rectifying tower is obviously reduced, so that the energy consumption is obviously reduced;
3. the chemical adsorbent or the inorganic membrane is adopted to separate water, so that the process is simple;
4. the continuous process has stable product quality and high propionate yield.
Drawings
FIG. 1 is a schematic view of an embodiment of the process of the present invention;
FIG. 2 is a schematic view of an embodiment of the process flow of the present invention;
FIG. 3 is a schematic view of an embodiment of the process flow of the present invention;
the reference numerals in the figures are explained below:
1, a first rectifying tower, 2, a water separation tank and 3, a second rectifying tower;
4a third rectifying tower, 5a first rectifying tower and 6 a second rectifying tower;
7 water knockout drum, 8 III rectifying tower, 9 IV rectifying tower.
Detailed Description
The present application will be described in detail with reference to examples, but the present application is not limited to these examples.
The invention takes propionic acid and various alcohols as raw materials, takes concentrated sulfuric acid, p-toluenesulfonic acid and sulfonic resin as catalysts, and obtains products of methyl propionate, ethyl propionate, propyl propionate and butyl propionate including isomers through the processes of reactive distillation, reactive separation and the like.
The specific process of the invention comprises the following steps:
the raw material propionic acid carries a certain amount of homogeneous catalyst and is fed from the top 1/4 of the first rectifying tower 1, and various alcohol raw materials are fed from the bottom of the first rectifying tower 1. The temperature of the top of the first rectifying tower 1 is controlled between 55 ℃ and 110 ℃, and the temperature of the bottom of the first rectifying tower 1 is controlled between 135 ℃ and 145 ℃. Propionic acid flows from the top of the first rectifying tower 1 to the bottom of the first rectifying tower 1 in a liquid phase state in the first rectifying tower 1, various alcohols flow from the bottom of the first rectifying tower 1 to the top of the first rectifying tower 1 in a gas phase state, and a gas-liquid two phase contacts and reacts in the first rectifying tower 1. The generated propionate, water and unreacted alcohol form binary or ternary azeotrope, the binary or ternary azeotrope continuously moves to the top of the first rectifying tower 1 in a gas phase mode, the closer to the top of the first rectifying tower 1, the higher the content of propionic acid is, the continuous reaction with various alcohols is carried out, the produced substances at the top of the first rectifying tower 1 are propionate and water, the alcohol content is lower than 3%, and alcohol raw materials are consumed by means of reactive distillation and a large amount of excess propionic acid. The bottom of the first rectifying tower 1 is excess propionic acid which is directly circulated to the top of the first rectifying tower 1. The light components extracted from the top of the first rectifying tower 1 are dehydrated by a calcium chloride and then dehydrated by a 4A or 5A molecular sieve, or enter the second rectifying tower 3 (product separation tower) after being dehydrated by an inorganic molecular sieve membrane, the propionate and the alcohol azeotrope extracted from the top of the second rectifying tower 3 circulate to the bottom of the first rectifying tower 1, and the product is separated from the bottom of the second rectifying tower 3. If the catalyst is a sulfonic acid resin heterogeneous catalyst, the catalyst is directly filled into a rectifying tower, and the propionic acid raw material does not need to carry the homogeneous catalyst.
In the present application, process I for the preparation of propanoates comprises the following process steps:
(1) raw material propionic acid is fed from the lower part of the top of the first rectifying tower 1, various alcohol raw materials are fed from the bottom of the first rectifying tower 1, the raw materials and the alcohol raw materials are in reverse contact in the first rectifying tower 1 and react under the action of a catalyst, excessive propionic acid at the tower top continuously consumes the alcohol raw materials, and a binary or ternary azeotropic system of propionate-alcohol-water is broken;
(2) the composition of the top of the first rectifying tower 1 is about more than 80 percent of propionate, less than 3 percent of alcohol and about 15 percent of water enter the second rectifying tower 3 for separation after dehydration,
(3) the propionic acid in the tower bottom of the first rectifying tower 1 circulates to a feed inlet at the tower top of the first rectifying tower 1;
(4) the azeotrope of the alcohol and the propionate extracted from the top of the second rectifying tower 3 is recycled to the bottom of the first rectifying tower 1, and the qualified propionate product is extracted from the bottom of the second rectifying tower 3.
The model of the gas chromatograph used in the present example was Shimadzu GC-2014C.
Example 1
As shown in figure 1, propionic acid and ethanol are used as raw materials to prepare ethyl propionate, the feeding molar ratio of the raw materials of the propionic acid and the ethanol is 4:1, the propionic acid is fed from 1/4 which is positioned below the top of a first rectifying tower 1, a catalyst adopts p-toluenesulfonic acid, the content of the catalyst is 1 percent of the mass fraction of the propionic acid, the catalyst is completely dissolved in the propionic acid, and the propionic acid moves from the top of the first rectifying tower 1 to the bottom of the first rectifying tower 1 in a liquid phase state. Ethanol is fed from the bottom of the first rectifying tower 1, flows from the bottom of the first rectifying tower 1 to the top of the first rectifying tower 1 in a gas phase, and is contacted and reacted in the first rectifying tower 1 in a gas-liquid two-phase mode. The number of the tower plates of the first rectifying tower 1 is 60, the height of the filler is 2m, the reflux ratio at the top of the first rectifying tower 1 is controlled to be 1:1-2:1, the temperature at the top of the first rectifying tower 1 is stabilized to be 80-85 ℃, the temperature at the bottom of the first rectifying tower 1 is 135-140 ℃, and the composition at the top of the first rectifying tower 1 is determined to be about 82.4 percent of ethyl propionate, 14.5 percent of water and 3.1 percent of ethanol. The water content can be reduced to 100ppm after the absorption of anhydrous calcium chloride and a 4A molecular sieve. The mixture enters a second rectifying tower 3 (the number of tower plates is 60) for separation, theta-ring packing is still adopted, the height of the packing is 2m, the reflux ratio of the top of the second rectifying tower 3 is controlled to be 1:1-2:1, the temperature of the top of the second rectifying tower 3 is 78-80 ℃, the temperature of the bottom of the second rectifying tower 3 is 98-100 ℃, and the composition of 55 percent ethanol and 45 percent ethyl propionate at the top of the second rectifying tower 3 is determined. Propionic acid in the bottom of the first rectifying tower 1 and additional supplemented propionic acid directly circulate to the top of the first rectifying tower 1, light components in the top of the second rectifying tower 3 and additional supplemented ethanol circulate to the bottom of the first rectifying tower 1, qualified ethyl propionate products are extracted from the bottom of the second rectifying tower 3, and the yield of single ethyl propionate can be close to 95%.
Example 2
As shown in figure 1, propionic acid and ethanol are used as raw materials to prepare ethyl propionate, the feeding molar ratio of the raw materials of the propionic acid and the ethanol is 4:1, the propionic acid is fed from 1/4 which is positioned below the top of a first rectifying tower 1, a catalyst adopts p-toluenesulfonic acid resin, the catalyst is filled into the first rectifying tower 1, and theta ring packing is filled in a way that one layer of catalyst is filled in one layer, and the height is about 8 cm. The propionic acid moves from the top of the first rectifying tower 1 to the bottom of the first rectifying tower 1 in a liquid phase state. Ethanol is fed from the bottom of the first rectifying tower 1, flows from the bottom of the first rectifying tower 1 to the top of the first rectifying tower 1 in a gas phase, and is contacted and reacted in the first rectifying tower 1 in a gas-liquid two-phase mode. The number of the tower plates of the first rectifying tower 1 is 60, the metal theta ring is filled, the height of the filler is 2m, the reflux ratio of the top of the first rectifying tower 1 is controlled to be 1:1-2:1, the temperature of the top of the first rectifying tower 1 is stabilized to be 80-85 ℃, the temperature of the bottom of the first rectifying tower 1 is 135-140 ℃, and the composition of ethyl propionate at the top of the first rectifying tower 1 is about 82.2%, 14.3% of water and 3.5% of ethanol through determination. The water content can be reduced to 100ppm after the absorption of anhydrous calcium chloride and a 4A molecular sieve. And (3) the mixture enters a second rectifying tower 3 (the number of tower plates is 60) for separation, theta-ring packing is still adopted, the height of the packing is 2m, the reflux ratio of the top of the second rectifying tower 3 is controlled to be 1:1-2:1, the temperature of the top of the second rectifying tower 3 is 78-80 ℃, the temperature of the bottom of the second rectifying tower 3 is 98-100 ℃, and the composition of the top of the second rectifying tower 3 is about 55% ethanol and 45% ethyl propionate through measurement. Propionic acid in the bottom of the first rectifying tower 1 and additional supplemented propionic acid directly circulate to the top of the first rectifying tower 1, light components in the top of the second rectifying tower 3 and additional supplemented ethanol circulate to the bottom of the first rectifying tower 1, qualified ethyl propionate products are extracted from the bottom of the second rectifying tower 3, and the yield of single ethyl propionate can be close to 95%.
Example 3
As shown in figure 2, the methyl propionate is prepared by taking propionic acid and methanol as raw materials, the feeding molar ratio of the propionic acid to the methanol is 4:1, the propionic acid is fed from 1/4 which is positioned below the top of a first rectifying tower 1, a catalyst adopts p-toluenesulfonic acid resin, the catalyst is filled in the rectifying tower, and the filling mode of theta ring packing is that one layer of catalyst is filled, one layer of packing is filled, and the height is about 10 cm. The propionic acid moves from the top of the first rectifying tower 1 to the bottom of the first rectifying tower 1 in a liquid phase state. Methanol is fed from the bottom of the first rectifying tower 1, flows from the bottom of the first rectifying tower 1 to the top of the first rectifying tower 1 in a gas phase, and is in gas-liquid two-phase contact and reaction in the first rectifying tower 1. The number of the tower plates of the first rectifying tower 1 is 60, the metal theta ring is filled, the height of the filler is 2m, the reflux ratio of the top of the first rectifying tower 1 is controlled to be 1:1-2:1, the temperature of the top of the first rectifying tower 1 is stabilized to be 67-73 ℃, the temperature of the bottom of the first rectifying tower 1 is 110-115 ℃, and the compositions of the top of the first rectifying tower 1 are about 95.5 percent of methyl propionate, 2.5 percent of water and 2 percent of methanol through determination. After gasification, water is separated by an inorganic molecular sieve membrane, and the water content can be reduced to 200 ppm. And (3) the mixture enters a second rectifying tower 3 (the number of tower plates is 60) for separation, theta-ring packing is still adopted, the height of the packing is 2m, the reflux ratio of the top of the second rectifying tower 3 is controlled to be 1:1-2:1, the temperature of the top of the second rectifying tower 3 is 59.5-62.5 ℃, the temperature of the bottom of the second rectifying tower 3 is 79-83 ℃, and the composition of the top of the second rectifying tower 3 is measured to be about 48 percent of methanol and 52 percent of methyl propionate. The bottom of the first rectifying tower 1 contains about 2-3% of water, the water enters a third rectifying tower 4 and is added with a toluene water-carrying agent for separation, the number of plates of the third rectifying tower 4 is 60, the height of a metal theta ring packing is 2m, the reflux ratio of the top of the third rectifying tower 4 is controlled to be 1:1-2:1, the temperature of the top of the third rectifying tower 4 is stabilized to be 83-88 ℃, and the temperature of the bottom of the third rectifying tower 4 is 115-120 ℃. Propionic acid in the kettle 4 of the third rectifying tower and additional supplementary propionic acid directly circulate to the top of the first rectifying tower 1, light components in the top of the second rectifying tower 3 and additional supplementary methanol circulate to the bottom of the first rectifying tower 1, qualified methyl propionate products are extracted from the bottom of the second rectifying tower 3, and the yield of single methyl propionate can exceed 95%.
Example 4
As shown in fig. 2, methyl propionate is prepared by using propionic acid and methanol as raw materials, the feed molar ratio of the propionic acid to the methanol is 4:1, the propionic acid is fed from the position 1/4 below the top of the first rectifying tower 1, the catalyst adopts concentrated sulfuric acid, the content of the catalyst is 1% of the mass fraction of the propionic acid, the catalyst is completely dissolved in the propionic acid, and the propionic acid moves from the top of the first rectifying tower 1 to the bottom of the first rectifying tower 1 in a liquid phase state. Methanol is fed from the bottom of the first rectifying tower 1, flows from the bottom of the first rectifying tower 1 to the top of the first rectifying tower 1 in a gas phase, and is contacted and reacted in the first rectifying tower 1 in a gas-liquid two-phase mode. The number of the tower plates of the first rectifying tower 1 is 60, the metal theta ring is filled, the height of the filler is 2m, the reflux ratio of the top of the first rectifying tower 1 is controlled to be 1:1-2:1, the temperature of the top of the first rectifying tower 1 is stabilized to be 67-73 ℃, the temperature of the bottom of the first rectifying tower 1 is 110-115 ℃, and the compositions of the top of the first rectifying tower 1 are about 95.6 percent of methyl propionate, 2.2 percent of water and 2.2 percent of methanol through determination. After gasification, water is separated by an inorganic molecular sieve membrane, and the water content can be reduced to 200 ppm. And (3) the mixture enters a second rectifying tower 3 (the number of tower plates is 55) for separation, theta-ring packing is still adopted, the height of the packing is 2m, the reflux ratio of the top of the second rectifying tower 3 is controlled to be 1:1-2:1, the temperature of the top of the second rectifying tower 3 is 59.5-62.5 ℃, the temperature of the bottom of the second rectifying tower 3 is 79-83 ℃, and the composition of the top of the second rectifying tower 3 is measured to be about 48 percent of methanol and 52 percent of methyl propionate. The bottom of the first rectifying tower 1 contains about 2-3% of water, the water enters a third rectifying tower 4 and is added with a toluene water-carrying agent for separation, the number of tower plates of the third rectifying tower 4 is 50, the height of a metal theta ring packing is 2m, the reflux ratio of the top of the third rectifying tower 4 is controlled to be 1:1-2:1, the temperature of the top of the third rectifying tower 4 is stabilized to be 83-88 ℃, and the temperature of the bottom of the third rectifying tower 4 is 115-120 ℃. Propionic acid in the kettle 4 of the third rectifying tower and additional supplementary propionic acid directly circulate to the top of the first rectifying tower 1, light components in the top of the second rectifying tower 3 and additional supplementary methanol circulate to the bottom of the first rectifying tower 1, qualified methyl propionate products are extracted from the bottom of the second rectifying tower 3, and the yield of single methyl propionate can exceed 95%.
Example 5
As shown in figure 3, propionic acid and methanol are used as raw materials to prepare methyl propionate, the feed molar ratio of the raw materials propionic acid and methanol is 1:6, the propionic acid, the methanol and 1% p-toluenesulfonic acid catalyst are uniformly mixed, and the mixture enters the middle part of a rectifying tower I5 after passing through a pre-reactor (50 ℃). The number of plates of the rectifying tower 5I is 60, the height of the filler is 2m, the reflux ratio of the tower top of the rectifying tower 5I is controlled to be 1:1-2:1, the temperature of the tower top of the rectifying tower 5I is stabilized to be 59.5-62.5 ℃, the temperature of the tower bottom of the rectifying tower 5I is stabilized to be 75-78 ℃, and the tower top of the rectifying tower 5I is measured to form about 48 percent of methanol and 52 percent of methyl propionate, and the water content is lower than 100 ppm. The light components extracted from the top of the rectifying tower I5 are mixed with about half of the mass of n-heptane and then enter the middle part of the rectifying tower II 6, the number of tower plates of the rectifying tower II 6 is 60, the height of a metal theta ring filler is 2m, the reflux ratio of the tower top of the rectifying tower II 6 is controlled to be 1:1-3:1, the temperature of the tower top of the rectifying tower II 6 is stabilized at 58-60 ℃, the temperature of a tower bottom of the rectifying tower II 6 is 61-63 ℃, the composition of the tower top of the rectifying tower II 6 is about 52 percent of methanol and 48 percent of n-heptane, the methanol and the n-heptane can be layered after being cooled and stood in a water separator 7, the methanol is circulated as a raw material, and the n-heptane is circulated as an entrainer. The composition of the first rectifying tower 5 kettle is less than 0.5 percent of propionic acid, about 79.5 percent of methanol and 20 percent of water, the water and the methanol do not have azeotropic boiling and are directly rectified, and the third rectifying tower 8 top extracts the methanol with the purity higher than 99.9 percent and circulates to the reaction raw materials. And (3) carrying out alkali washing on the propionic acid-containing water solution at the tower bottom of the third rectifying tower 8 to reach a neutral pH value, and then discharging to a water-free treatment plant. The product from column II, rectification column 6, had a composition of about 0.5% methanol, 3% n-heptane and 96.5% methyl propionate. The product from the 6 th tower bottom of the II rectifying tower enters the middle part of the III rectifying tower 8, the number of tower plates of the III rectifying tower 8 is 30, metal theta ring packing is filled, the height of the packing is 1m, the reflux ratio of the top of the III rectifying tower 8 is controlled to be 1:1-2:1, the temperature of the top of the III rectifying tower 8 is 79-81 ℃, the tower bottom of the III rectifying tower 8 is 98-100 ℃, and the top of the III rectifying tower 8 extracts methyl propionate with the content higher than 99.9 percent. And n-heptane at the bottom of the rectifying tower 8 of the III is recycled to the entrainer for recycling. And (3) separating methanol and water at the bottom of the rectifying tower 5 of the rectifying tower I from the rectifying tower IV 9 (the tower top temperature of the rectifying tower IV 9 is 65 ℃, the tower bottom temperature of the rectifying tower IV is 100.5 ℃, and the operation reflux ratio of the tower top is 2: 1), wherein the methanol and the water are not subjected to azeotropic distillation, and the methanol at the top of the rectifying tower IV 9 is recycled to the reaction raw materials.
Example 6
As shown in figure 3, propionic acid and methanol are used as raw materials to prepare methyl propionate, the feeding molar ratio of the raw materials of the propionic acid and the methanol is 1:6, the propionic acid and the methanol pass through a packed p-toluenesulfonic acid fixed bed reactor (namely a pre-reactor), the reaction temperature is 60-100 ℃, and then the propionic acid and the methanol enter the middle part of a rectifying tower I5 (a p-toluenesulfonic acid solid catalyst is packed in the rectifying tower I5, and the packing mode of the catalyst and theta ring packing is a layer of catalyst and a layer of packing, and the height is about 7 cm). The number of plates of the rectifying tower 5I is 60, the height of the filler is 2m, the reflux ratio of the tower top of the rectifying tower 5I is controlled to be 1:1-2:1, the temperature of the tower top of the rectifying tower 5I is stabilized to be 59.5-62.5 ℃, the temperature of the tower bottom of the rectifying tower 5I is stabilized to be 75-78 ℃, and the tower top of the rectifying tower 5I is measured to form about 48 percent of methanol and 52 percent of methyl propionate, and the water content is lower than 100 ppm. The light component extracted from the top of the first rectifying tower 5 is mixed with half of the mass of n-heptane and then enters the middle part of the second rectifying tower 6, the number of tower plates of the second rectifying tower 6 is 60, the height of the filler is 2m, the reflux ratio of the top of the second rectifying tower 6 is controlled to be 1:1-3:1, the temperature of the top of the second rectifying tower 6 is stabilized at 58-60 ℃, the temperature of a bottom of the second rectifying tower 6 is 61-63 ℃, the composition of the top of the second rectifying tower 6 is 52% of methanol and 48% of n-heptane, the methanol and the n-heptane can be layered after being cooled and settled in the water separator 7, the methanol is circulated as a raw material, and the n-heptane is circulated as an entrainer for use. The composition of the first rectifying tower 5 kettle is less than 0.5% propionic acid, about 79.5% methanol and 20% water, the water and the methanol do not azeotropy, the water is directly rectified in the IV rectifying tower 9, the purity of the methanol extracted from the top of the IV rectifying tower 9 is more than 99.9%, and the methanol is circulated to the reaction raw material. And (3) carrying out alkaline washing on the propionic acid-containing water solution in the tower 9 of the IV rectifying tower to reach neutral pH value, and then discharging the propionic acid-containing water solution to a sewage treatment plant. The product from column II, rectification column 6, had a composition of about 0.5% methanol, 3% n-heptane and 96.5% methyl propionate. The product from the 6 th tower of the II rectifying tower enters the middle part of the III rectifying tower 8, the number of tower plates of the III rectifying tower 8 is 20-30, metal theta ring packing is filled, the height of the packing is 1m, the reflux ratio at the top of the III rectifying tower 8 is controlled between 1:1 and 2:1, the temperature at the top of the III rectifying tower 8 is 79-81 ℃, the 98-100 ℃ of the 8 th tower of the III rectifying tower is realized, and the methyl propionate with the content higher than 99.9 percent is extracted from the top of the III rectifying tower 8. And n-heptane at the bottom of the rectifying tower 8 of the III is recycled to the entrainer for recycling. And (3) separating methanol and water at the bottom of the tower 5 of the rectifying tower I from the rectifying tower IV 9 (the tower top temperature of the rectifying tower IV 9 is 65 ℃, the tower bottom temperature of the tower is 100.5 ℃, and the operation reflux ratio of the tower top is 2: 1), wherein the methanol and the water are not subjected to azeotropic distillation, and the methanol at the tower top of the rectifying tower IV 9 is recycled to the reaction raw materials.
Example 7
As shown in fig. 1, propionic acid and n-propanol are used as raw materials to prepare propyl propionate, the feeding molar ratio of the raw materials of the propionic acid and the n-propanol is 4:1, the propionic acid is fed from the position 1/4 below the top of the first rectifying tower 1, the catalyst adopts p-toluenesulfonic acid, the content of the catalyst is 1% of the mass fraction of the propionic acid, the catalyst is completely dissolved in the propionic acid, and the propionic acid moves from the top of the first rectifying tower 1 to the bottom of the first rectifying tower 1 in a liquid phase state. The n-propanol is fed from the bottom of the first rectifying tower 1, flows from the bottom of the first rectifying tower 1 to the top of the first rectifying tower 1 in a gas phase, and is contacted and reacted in the first rectifying tower 1 in a gas-liquid two-phase manner. The number of the tower plates of the first rectifying tower 1 is 60, the metal theta ring is filled, the height of the filler is 2m, the reflux ratio of the top of the first rectifying tower 1 is controlled to be 1:1-2:1, the temperature of the top of the first rectifying tower 1 is stabilized to be 88-103 ℃, the temperature of the bottom of the first rectifying tower 1 is 140-145 ℃, and the compositions of the top of the first rectifying tower 1 are about 83.5 percent of propyl propionate, 13 percent of water and 3.5 percent of n-propanol through determination. After gasification, the water content is reduced to 200ppm by dehydration through an inorganic molecular sieve membrane. The propionic acid in the bottom of the first rectifying tower 1 and the additional supplemented propionic acid are directly circulated to the top of the first rectifying tower 1. The propyl propionate and the n-propanol are not azeotropic and enter a second rectifying tower 3 (the number of tower plates is 60) for separation, the n-propanol is extracted at the temperature of 97-100 ℃ at the top of the second rectifying tower 3 and is recycled to the reaction raw material, the temperature of the tower bottom of the second rectifying tower 3 is 118-.
Example 8
As shown in fig. 1, propionic acid and n-propanol are used as raw materials to prepare propyl propionate, the feeding molar ratio of the raw materials of the propionic acid and the n-propanol is 4:1, the propionic acid is fed from the position 1/4 below the top of the first rectifying tower 1, the catalyst adopts p-toluenesulfonic acid, the content of the catalyst is 1% of the mass fraction of the propionic acid, the catalyst is completely dissolved in the propionic acid, and the propionic acid moves from the top of the first rectifying tower 1 to the bottom of the first rectifying tower 1 in a liquid phase state. The normal propyl alcohol is fed from the bottom of the first rectifying tower 1, flows from the bottom of the first rectifying tower 1 to the top of the first rectifying tower 1 in a gas phase, and is in gas-liquid two-phase contact and reacts in the first rectifying tower 1. The number of the tower plates of the rectifying tower is 60, the metal theta ring is filled, the height of the filler is 2m, the reflux ratio of the top of the first rectifying tower 1 is controlled to be 1:1-2:1, the temperature of the top of the first rectifying tower 1 is stabilized to be 88-103 ℃, the temperature of the bottom of the first rectifying tower 1 is 140-145 ℃, and the compositions of the top of the first rectifying tower 1 are determined to be about 83.5 percent of propyl propionate, 13 percent of water and 3.5 percent of n-propanol. After gasification, the water content is reduced to 200ppm by dehydration through an inorganic molecular sieve membrane. The propionic acid in the bottom of the first rectifying tower 1 and the additional supplemented propionic acid are directly circulated to the top of the first rectifying tower 1. The propyl propionate and the n-propanol are not subjected to azeotropy and enter a second rectifying tower 3 (the number of tower plates is 60) for separation, the n-propanol is extracted at the temperature of 97-100 ℃ at the top of the second rectifying tower 3 and is recycled to the reaction raw material, the temperature of 118 in the tower bottom of the second rectifying tower 3 is 123 ℃, and the propyl propionate is extracted at the bottom of the second rectifying tower 3.
Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.
Claims (10)
1. An apparatus I, comprising: a first rectification column; a propionic acid inlet is formed in the top of the first rectifying tower; an alcohol compound inlet is formed in the bottom of the first rectifying tower;
and an intermediate product gas outlet is formed in the top of the first rectifying tower.
2. The device I according to claim 1, characterized in that a propionic acid outlet is further arranged at the bottom of the first rectifying tower;
the propionic acid outlet is connected with a propionic acid inlet at the top of the first rectifying tower;
preferably, the height of the propionic acid inlet from the top of the first rectifying tower is 1/6-1/2 of the total tower height;
the height from the alcohol compound inlet to the tower kettle of the first rectifying tower is 0-1/2 of the total tower height;
the propionic acid inlet is higher than the alcohol compound inlet;
preferably, the number of the trays of the first rectifying tower is 40-60;
preferably, the device I further comprises a water separation tank and a second rectifying tower;
the inlet end of the water diversion tank is connected with the top of the first rectifying tower, and the outlet end of the water diversion tank is connected with the top of the second rectifying tower;
preferably, the number of plates of the second rectifying column is 30 to 80;
preferably, the water separation tank comprises at least one of a molecular sieve and anhydrous calcium chloride;
preferably, the second rectification column top is connected with the first rectification column bottom so that the second rectification column top stream is passed to the first rectification column bottom;
a propionate outlet is formed in the tower kettle of the second rectifying tower;
preferably, the device I further comprises a third rectification column; the first rectifying tower kettle is connected with the top of the third rectifying tower, so that the material flow of the third rectifying tower kettle is introduced into the third rectifying tower;
the tower kettle of the third rectifying tower is connected with the top of the first rectifying tower, so that the material flow of the tower kettle of the third rectifying tower is introduced into the first rectifying tower;
preferably, the number of plates of the third rectifying column is 30 to 60.
3. A process I for the preparation of propanoates, characterized by being carried out using the apparatus I according to claim 1 or 2.
4. Process I according to claim 3, characterized in that it comprises the following process steps:
(1) introducing a raw material I containing propionic acid from the top of a first rectifying tower, introducing a raw material II containing alcohol compounds from the bottom of the first rectifying tower, reacting, and obtaining the intermediate product gas containing propionic ester at the top of the first rectifying tower;
filling a catalyst I in the first rectifying tower or containing the catalyst I in a raw material I containing propionic acid;
the molar ratio of the propionic acid to the alcohol compound is 2: 1-10: 1;
preferably, the step (1) comprises: the raw material I and the raw material II react in the first rectifying tower to generate a gas-phase azeotrope containing propionate, the gas-phase azeotrope flows towards the top of the first rectifying tower and continuously reacts with the raw material I fed from the top of the first rectifying tower to generate an intermediate product gas containing propionate;
preferably, the intermediate product gas also contains water and alcohol compounds;
the content of the alcohol compound in the intermediate product gas is 0-3 wt%;
preferably, in the raw material I containing propionic acid, the mass content of the catalyst I is 0.5-3%;
preferably, the alcohol compound is selected from at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and tert-butanol;
preferably, the catalyst I is selected from any one of homogeneous catalysts, heterogeneous catalysts;
preferably, the process operating conditions of the first rectifying tower are as follows: the temperature of the tower top is 55-110 ℃; the temperature of the tower kettle is 135-150 ℃; the reflux ratio of the tower top is 1:1-2: 1;
preferably, the propionic acid obtained from the tower bottom of the first rectifying tower is recycled to the tower top of the first rectifying tower for use;
preferably, the method also comprises the following process steps:
(2) introducing a material flow containing propionate obtained at the top of the first rectifying tower into a water separation tank;
(3) introducing a material flow obtained after dehydration in the water diversion tank into the top of a second rectifying tower, circulating the material flow extracted from the top of the second rectifying tower to the kettle of the first rectifying tower, and obtaining the propionate in the kettle of the second rectifying tower;
preferably, the process operating conditions of the second rectifying tower are as follows: the temperature of the tower top is 50-80 ℃; the temperature of the tower kettle is 80-120 ℃; the reflux ratio of the tower top is 1:1-2: 1;
preferably, the water content of the material flow obtained after dehydration in the water separation tank is less than or equal to 500 ppm;
preferably, the method also comprises the following process steps:
(4) introducing the material flow obtained at the bottom of the first rectifying tower into the top of a third rectifying tower, introducing the material flow at the bottom of the third rectifying tower into the top of the first rectifying tower, and returning the material flow at the top of the third rectifying tower to the top of the third rectifying tower;
a water carrying agent is filled in the third rectifying tower;
preferably, the water-carrying agent is selected from any one of toluene, benzene, toluene and cyclohexane;
preferably, the process operating conditions of the third rectifying tower are as follows: the temperature of the tower top is 80-100 ℃; the temperature of the tower kettle is 90-130 ℃; the reflux ratio of the tower top is 1:1-2: 1.
5. An apparatus II, comprising: a first rectifying tower and a second rectifying tower;
the top of the rectifying tower I is provided with an inlet for propionic acid and alcohol compounds;
the top of the first rectifying tower is connected with the top of the second rectifying tower, so that the material flow at the top of the first rectifying tower is introduced into the top of the second rectifying tower;
an entrainer inlet is formed in the top of the rectifying tower II; or the like, or, alternatively,
the top of the rectifying tower I is connected with the top of the rectifying tower II through a pipeline; the pipeline is provided with an entrainer inlet.
6. The apparatus II according to claim 5, further comprising a water separator;
the inlet of the water separator is connected with the tower top of the second rectifying tower, so that the tower top material flow of the second rectifying tower is introduced into the water separator;
the outlet of the water separator is respectively connected with the propionic acid inlets at the top of the rectifying tower II and the top of the rectifying tower I;
preferably, the number of the plates of the rectifying tower I and the number of the plates of the rectifying tower II are 40-60;
preferably, the device II further comprises a III rectifying tower;
the tower kettle of the II rectifying tower is connected with the top of the III rectifying tower, so that the tower kettle material flow of the II rectifying tower is introduced into the top of the III rectifying tower;
the tower kettle of the III rectifying tower is connected with an entrainer inlet at the top of the II rectifying tower, so that the tower kettle material flow of the III rectifying tower is introduced into the top of the II rectifying tower;
preferably, the number of the plates of the III rectifying tower is 40-60;
preferably, the device II further comprises an IV rectifying tower;
the tower kettle of the I rectifying tower is connected with the top of the IV rectifying tower, so that the material flow of the tower kettle of the I rectifying tower is introduced into the top of the IV rectifying tower;
the top of the IV rectifying tower is connected with a propionic acid inlet at the top of the I rectifying tower, so that the top stream of the IV rectifying tower is introduced into the top of the I rectifying tower;
preferably, the number of plates of the IV rectifying tower is 40-60;
preferably, the apparatus II further comprises a pre-reactor;
one end of the pre-reactor is provided with a propionic acid and alcohol compound inlet; the other end of the prereactor is connected with the top of the rectifying tower I.
7. A process II for the preparation of propanoates, characterized by the fact that it is carried out using the apparatus II according to claim 5 or 6.
8. Process II according to claim 7, characterized in that it comprises the following process steps:
(a) introducing raw materials containing propionic acid and alcohol compounds into the top of a first rectifying tower, reacting in the first rectifying tower, mixing material flow obtained at the top of the first rectifying tower with material flow containing an entrainer, introducing the mixture into the top of a second rectifying tower, and obtaining the propionate in the bottom of the second rectifying tower;
the catalyst II is filled in the rectifying tower I or contained in the raw material containing the propionic acid and the alcohol compound;
preferably, the catalyst II is selected from any one of homogeneous catalysts, heterogeneous catalysts;
preferably, the molar ratio of the propionic acid to the alcohol compound is 1: 1-1: 10;
preferably, in the raw material containing propionic acid and alcohol compounds, the mass content of the catalyst II is 1-2%;
preferably, the process operating conditions of the rectifying tower I are as follows: the temperature of the tower top is 55-110 ℃; the temperature of the tower kettle is 135-150 ℃; the reflux ratio of the tower top is 1:1-2: 1;
the process operation conditions of the rectifying tower II are as follows: the temperature of the tower top is 60-80 ℃; the temperature of the tower kettle is 80-100 ℃; the reflux ratio of the tower top is 1: 1-2;
preferably, in the step (a), the mass ratio of the stream obtained at the top of the I rectifying tower to the entrainer is 1: 0.5 to 2;
preferably, material flow obtained at the top of the rectifying tower II is subjected to standing and then demixing, alcohol compounds obtained after demixing are recycled to reaction raw materials, and obtained n-heptane is recycled to the top of the rectifying tower II;
preferably, in the step (a), the raw material containing propionic acid and alcohol compounds is pre-reacted in a pre-reactor and then is introduced into the top of the I rectifying tower;
the pre-reactor is filled with the catalyst II or the raw material containing the propionic acid and the alcohol compound contains the catalyst II.
9. The process II according to claim 8, further comprising the process steps of:
(b) introducing the material flow obtained from the tower bottom of the II rectifying tower to the top of a III rectifying tower, obtaining the propionate from the tower top of the III rectifying tower, and introducing the material flow obtained from the tower bottom of the III rectifying tower to the top of the II rectifying tower;
preferably, the process operating conditions of the III rectifying tower are as follows: the temperature of the tower top is 70-90 ℃; the temperature of the tower kettle is 90-110 ℃; the reflux ratio of the tower top is 1:1-2: 1.
10. process II according to claim 9, characterized in that it further comprises the following process steps:
(c) introducing the material flow obtained from the tower bottom of the I rectifying tower into an IV rectifying tower, and circulating the material flow obtained from the tower top of the IV rectifying tower to the top of the I rectifying tower for recycling;
preferably, the process operating conditions of the IV rectifying tower are as follows: the temperature of the tower top is 60-70 ℃; the temperature of the tower kettle is 99-105 ℃; the reflux ratio of the tower top is 1:1-2: 1.
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| CN202011519008.0A CN114644556A (en) | 2020-12-21 | 2020-12-21 | Device and process method for preparing propionate |
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| CN202011519008.0A CN114644556A (en) | 2020-12-21 | 2020-12-21 | Device and process method for preparing propionate |
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| CN104649902A (en) * | 2013-11-19 | 2015-05-27 | 中国石油天然气股份有限公司 | Production method of sec-butyl acetate |
| CN207944042U (en) * | 2017-12-26 | 2018-10-09 | 东营市海科新源化工有限责任公司 | A kind of process system preparing propionic ester |
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