CN1112546A

CN1112546A - Semi-continuous producing process for ethyl formate

Info

Publication number: CN1112546A
Application number: CN 95103725
Authority: CN
Inventors: 吴梦海
Original assignee: STATE-OWNED WUJIANG PERFUMERY
Current assignee: STATE-OWNED WUJIANG PERFUMERY
Priority date: 1995-04-17
Filing date: 1995-04-17
Publication date: 1995-11-29
Anticipated expiration: 2015-04-17
Also published as: CN1039226C

Abstract

In the new process for production of ethyl formate, formic acid and ethyl alcohol are used as raw material, sulfuric acid is used as catalyst, and a new prescription and a semicontinuous esterifying process are used, and thus the yield rate is up to 95.4%. Advantage: less raw material consumption, low production cost, good quality of the product, it is suitable for production of ethyl formate of perfume grade, medicine grade and reagent grade.

Description

Semi-continuous producing process for ethyl formate

The present invention relates to the production technique of ethyl formate, particularly the production technique of spices level, pharmaceutical grade and SILVER REAGENT ethyl formate.

Ethyl formate is the unsettled liquid of water white transparency, and facile hydrolysis can be miscible with benzene, ether, ethanol, is slightly soluble in water.Ethyl formate is used to prepare fruit type food flavour and wine essence in foodstuffs industry, also be the raw material of pharmaceutical industry and the raw material of organic synthesis industry, also is widely used as solvent, fumigant, larvacide etc.

Chinese patent index CD-ROM CD, Chinese patent classification annual index, U.S. chemical abstract (C.A.) and world patent document (WP1, WPA) before the present invention makes, still find no the production technique similar to the present invention by retrieval.More representational document about the ethyl formate synthetic method, for example: " (institute of scientific-technical information of Ministry of Chemical Industry edits and publishes world's fine chemistry industry handbook, December nineteen eighty-two the 1st edition, 457 pages), " synthetic flavor handbook (light industry press, December in 1985 the 1st edition, 360 pages) in, sketched Japan, the manufacture method of the ethyl formate of the U.S., (institute of scientific-technical information of Ministry of Chemical Industry compiles " the Chemicals handbook-Organic Chemicals first volume ", Chemical Industry Press, February in 1985 the 1st edition, 263 pages) in introduced the operational path of domestic five tame factories, but the present invention and these production technique and inequality.

Owing to contain in the formic acid and contain the water that again generation is accounted for ethyl formate weight 24% in 7～8% water, the esterification reaction process in 15～16% water, the ethanol, and ethyl formate very easily hydrolysis again, so how water a large amount of in the esterification system is removed, be the key point of ethyl formate preparation always.

Present domestic ethyl formate manufacturer adopts traditional single pot of esterification technique intermittently mostly, this technology is that the intrasystem water of esterification is removed from cat head, be summarized as follows: formic acid and ethanol add a small amount of sulfuric acid as catalyzer, the reflux esterification by a certain proportion ingredient; Constantly water is told from the water trap that is arranged in cat head with the form of ternary azeotrope during the backflow esterification, be that ethyl formate, second alcohol and water steam from cat head with the form of azeotrope, after the condensation cooling, enter the water trap layering, the ester on upper strata, alcohol mixture (saturated by water) pass back into cat head, and the water of lower floor (by ester, pure saturated) shifts out the esterification system; After the dehydration esterification finished, 64～100 ℃ fraction was collected in distillation, and the ethyl formate that has generated in the esterification pot, unreacted formic acid and ethanol are all steamed; The siccative that adds anhydrous sodium sulphate, Calcium Chloride Powder Anhydrous and so in steaming liquid carries out drying, filters then; Filtrate is carried out fractionation, and the fraction of collecting 53～58 ℃ is as the ethyl formate finished product.By this technology, the productive rate of formic acid is generally about 80%.This traditional technology mainly exists problems such as raw material consumption height, equipment capacity is low, the production cycle is long.

The object of the present invention is to provide a kind of productive rate height, good economy performance, equipment capacity is big and the reliable ethyl formate new process of production of stable operation.

The objective of the invention is to realize by following method: with formic acid (content 84～85%) and ethanol (content 92～93%) is raw material, with sulfuric acid is catalyzer, the bed material proportioning is a formic acid: ethanol=1: 2.5～5.0(mol ratio), dripping the material proportioning is formic acid: ethanol=1: 1.0～1.1(mol ratio); After treating that the bed material esterification reaches balance substantially, to drip material adds in the esterification pot continuously, simultaneously ethyl formate is steamed from the esterification column cat head continuously, after the condensation cooling, 60～65% of ethyl formate total amount is returned into cat head as phegma, and remaining shifts out the esterification system as finished product.In whole semicontinuous esterification technique process, control by proportioning raw materials, and rate of addition, return velocity, discharging speed and temperature controlling, make second alcohol and waters a large amount of in the ethyl formate of generation and the esterification system not form azeotrope, thereby the ethyl formate that the esterification column cat head is steamed has just reached the spices grade standard without rectifying, and the intrasystem water of esterification is almost all stayed in the esterification pot, what discharge in the esterification pot at last almost is pure water.As above-mentioned spices level ethyl formate is adopted the ethylene glycol extracting rectifying, promptly reach pharmaceutical grade and SILVER REAGENT standard.

The nearly 3 years production practice of State-Owned Wujiang Perfumery prove, the present invention compared with prior art, have the following advantages: (1) raw material consumption is low, productive rate is high (in the ethyl formate of content 95.5% per ton, 0.736 ton of formic acid unit consumption, 0.765 ton of ethanol unit consumption, the productive rate of formic acid reaches 95.4%, improves 10～15% than prior art); (2) equipment capacity (reactor with unit volume calculates) improves about 4.1 times; (3) good product quality (just can reach the spices grade standard) without rectifying.

Accompanying drawing 1 is the processing unit sketch of the semicontinuous esterification of ethyl formate.

Among the figure: esterification pot [1], esterification column [2], condenser [3], water cooler [4], liquid vessel [5], under meter [6], [7], [8] and other utility appliance, as thermometer [T], tensimeter [P] etc.

The present invention is explained in detail by embodiment below in conjunction with accompanying drawing 1:

1. it is raw material that the present invention for preparing burden adopts formic acid (content 84～85%) and ethanol (content 92～93%), with sulfuric acid is catalyzer, the bed material proportioning is a formic acid: ethanol=1: 2.5～5.0(mol ratio), dripping the material proportioning is formic acid: ethanol=1: 1.0～1.1(mol ratio).

2. the total reflux esterification adds the vitriol oil of bed material and bed material weight 0.8～1.0% in 1000 liters of esterification pots [1], in the chuck of esterification pot [1], feed steam, open and stir, heating total reflux esterification is about 1 hour, when the tower top temperature of esterification column [2] was stabilized in 53.5～54.0 ℃, the total reflux esterification finished.

3. after semicontinuous esterification total reflux esterification process finishes, promptly begin semicontinuous esterification operation.Under 54.0～54.1 ℃ of control tower top temperatures and material turnover EQUILIBRIUM CONDITION, to drip the bottom of expecting to add continuously by 200～300 liters/hour speed esterification pot [1] through under meter [6], simultaneously ethyl formate is steamed from the top of esterification column [2] continuously, behind condenser [3], water cooler [4], enter liquid vessel [5], part ethyl formate steams liquid and passes back into cat head through under meter [7] by 200～450 liters/hour speed, and another part ethyl formate steams liquid and shifts out reactive system through under meter [8] by 100～300 liters/hour speed.The dropping material weight that proceeds to adding when whole semicontinuous esterification process is 14～15 times of bed material formic acid weight and esterification column tower top temperature when being higher than 54.1 ℃, pot internal reaction liquid temps and reaching 75 ℃, drips and finishes.When the esterification column tower top temperature is higher than 54.5 ℃, pot internal reaction liquid temps and reaches 78 ℃, stop to collect ethyl formate.Merge above-mentioned ethyl formate and steam liquid, promptly can be used as spices level ethyl formate.Merge above-mentioned ethyl formate and steam liquid, promptly can be used as spices level ethyl formate.Prepare pharmaceutical grade and SILVER REAGENT ethyl formate as need, then adopt the ethylene glycol extracting rectifying to get final product above-mentioned spices level ethyl formate.

4. after regaining the end of collection ethyl formate, begin collection and contain ester ethanol.Contain the ester ethanol preparation bed material that after content conversion, is used to cook.Finish when ester ethanol is collected tower top temperature and is higher than that the liquid temperature reaches 88 ℃ in 78.0 ℃, pots when containing.

Collection begins to collect light ethanol after containing the end of ester ethanol.Light ethanol is used to cook after concentrating and prepares bed material or drip material.When collecting tower top temperature and be higher than that the liquid temperature reaches 98 ℃ in 95.0 ℃, pots, finishes by light ethanol.At this moment, remaining in the pot is almost pure water, and its weight is 4.3～4.5 times of bed material formic acid weight, and this waste water discards.

Now select the ethyl formate of four lot numbers, as follows with spices level (U.S. FCC III), pharmaceutical grade, SILVER REAGENT (chemical pure) standard control:

Test result shows, the ethyl formate that adopts semicontinuous esterification technique to produce just reaches the spices grade standard without rectifying, after rectifying, just can reach pharmaceutical grade and SILVER REAGENT standard.

Claims

1, semi-continuous producing process for ethyl formate, it comprises that with formic acid and ethanol be raw material, with sulfuric acid is catalyzer, produce ethyl formate through processes such as batching, esterification (or again through extracting rectifying) and withdrawals, it is characterized in that: determined bed material and dripped the rational proportion of expecting, the proportioning of bed material is a formic acid: ethanol=1: 2.5～5.0 (mol ratio), and the proportioning that drips material is a formic acid: ethanol=1: 1.0～1.1 (mol ratio); After treating that the bed material esterification reaches balance substantially, under control tower top temperature and material turnover EQUILIBRIUM CONDITION, to drip material adds in the esterification pot continuously, simultaneously ethyl formate is steamed from the esterification column cat head continuously, after the condensation cooling, 60～65% of ethyl formate total amount is returned into cat head as phegma, and remaining shifts out the esterification system as finished product, and the water that produces in contained water and the esterification reaction process in raw material formic acid and the ethanol is retained in the esterification pot.

2, novel process according to claim 1 is characterized in that in whole semicontinuous esterification process, the turnover balance of material is a dripping quantity: quantity of reflux: load=1: 1.0～1.5: 0.5～1.0(volume ratio).

3, novel process according to claim 1, it is characterized in that dropping material weight that whole semicontinuous esterification process proceeds to adding is 14～15 times of bed material formic acid weight, and when the esterification column tower top temperature is higher than 54.1 ℃, pot internal reaction liquid temps and reaches 75 ℃, drip and finish.When the esterification column tower top temperature is higher than 54.5 ℃, pot internal reaction liquid temps and reaches 78 ℃, stop to collect ethyl formate.