化學(xué) 工程與工藝 畢業(yè)設(shè)計(jì) 外文 英文 文獻(xiàn) 翻譯 醋酐生產(chǎn)工藝

1、acetic anhydride production process acetic anhydride is a colorless volatile, with a strong irritating smell and corrosiveness liquid. name of acetic anhydride, molecular formula c4h6o3, the flash point of 64.4 deg c. density of 1.082 0g / cm3. melting point - 74.13 deg c. the boiling point of 138.6

2、3 deg c. the refractive index nd 1.390. 20 degrees of viscosity of 0.91 mpa? s. spontaneous ignition temperature of 388.9 deg c. soluble in cold water, in water is decomposed into acetic acid, ethyl acetate and ethanol production. soluble in chloroform, ether and benzene. toxic, eye and mucosa has a

3、 strong irritating, mass concentration of 0.36 mg / m3 when the eye irritation; 0.18mg / m3, can change a persons brain electrical image, can cause tissue protein modification. the steam stimulation is stronger, extremely easy to burn the skin and eyes, such as frequent exposure can cause dermatitis

4、 and chronic conjunctivitis. on rat oral ld50 was 1780 mg / kg. when spilled and or adhesion to the skin, to immediately with water or 2% washing soda, systemic poisoning should be timely medical treatment. air max allowable volume fraction 5 u l / l. acetic anhydride is the country to encourage the

5、 development of basic organic chemical raw materials, mainly used for the production of cellulose acetate, of which two cellulose acetate is used in the manufacture of cigarette filter tip and plastic, three cellulose acetate is the manufacturing of advanced film material, is widely used in medicine

6、, pesticides, dyes, military, spices, metal finishing industries.acetic anhydride is precursor products, acetic anhydride production, management must be in the public security organ for archival filing certification, enterprises sold every batch of goods to perform detailed registration, and to the

7、public security organ for the record. according to the legal provisions, to undocumented units 200 kg acetic anhydride, will be sentenced to 3 years imprisonment. industrialization of acetic anhydride production process has three kinds: the oxidation of acetaldehyde, ethylene ketone and methyl aceta

8、te carbonylation. acetaldehyde oxidation technology source for the canadian sha winigan chemical company. the production process is as follows: acetaldehyde and oxygen at 60 degrees c, 101 kpa or 70 degrees c, 600-700kpa under the conditions of the oxidation reaction, oxygen or air as the oxidant, u

9、sing ethyl acetate as solvent, cobalt acetate as catalyst, acetic acid copper as promoter. acetaldehyde and oxygen ( in excess of about 1%-2%) reaction is first generated peroxy acetic acid, acetic acid and acetaldehyde reaction of acetic anhydride and acetic acid. under this condition, the conversi

10、on rate of acetaldehyde acetic anhydride and acetic acid production rate is 95%, the mass ratio of 56: 44. the total yield of 70%-75% acetic anhydride. by changing the processing conditions, can improve the yield of acetic anhydride. reaction equation:ch3cho+o2 - ch3coooh;ch3coooh+ch3cho ch3coooch (

11、 oh )ch3 ( single peroxy acetic ester );ch3coooch ( oh ) ch3 - ( ch3co ) 2o+h2o;ch3coooch ( oh ch3 2ch3cooh ). acetaldehyde acetic anhydride consumption per ton of 1.165 t, 2300 m3 standard air. acetaldehyde oxidation method has the advantages of simple process, technology is mature, but the serious

12、 corrosion, high consumption, has gradually been eliminated. in foreign countries have been carbonylation of methyl acetate and vinyl ketone method alternative. china shanghai chemical reagent factory of this device has been in a state of production. vinyl ketone law in accordance with the different

13、 materials can be divided into: acetic acid and acetone method. acetic acid process technology from germany wacher chemical company. the production process is as follows: in the first step, the acetic acid in 700-750 c, 10-20kpa pressure and 0.2%-0.3% phosphoric acid three ethyl ester (by acetic aci

14、d quality plan) as catalyst under the conditions of dehydration, cracking ethylene ketone acetate made, conversion rate is about 85%-90%, on vinyl ketone selectivity (corporeal quantity meter ) is about 90%-95%. reaction equation:ch3cooh ch2 = c = o+h2o+147 kj / mol. the second step is to absorb liq

15、uid acetic acid ethylene ketone anhydride generating, by distillation and purification to obtain the product of acetic anhydride, vinyl ketone conversion rate of about 100%. reaction equation:ch3cooh+ch2 = c = o ( ch3co ) 2o+62.8kj / mol. the production process is a german wacher chemical company to

16、 develop a success, and in 1936 achieved industrialization. two existing production process: one, as the tower process. using 4 packed tower for synthesis and separation. the consumption of per ton of acetic anhydride as catalyst, acetic acid 1.35t, 1.5-2kg 0.7-1.0kg 100-160kg, ammonia, acetic acid

17、recovery. secondly, as the liquid ring pump flow. the liquid ring pump for reaction and absorption equipment. the process is simple, being replaced by tower process. per ton of products consumption quota for acetic acid cracking rate, 1.22 t, 75%, the yield of synthesis of 96%. the production proces

18、s is as follows: the first step is to acetone in 700-800 c, atmospheric pressure, no catalyst under the conditions of the cleavage reaction. reaction equation:ch3coch3 ch2 = c = o+ch4-79.53 kj / mol. the second step is to absorb the liquid acetic acid ethylene ketone anhydride generating. reaction e

19、quation:ch2 = c = o+ch3cooh ( ch3co ) 2o+62.8kj / mol. but in the same scale, acetone and acetic acid, acetone method requires larger cracking furnace, absorption tower and the washing tower, and an increase in cyclic acetone water distillation separation and other auxiliary equipment, the project c

20、onstruction cost is high. at the same time, the production cost is also higher acetone method. ketene process relative acetaldehyde oxidation and carbonylation of methyl acetate to the process, the process is complex, a lot of side reactions, high energy consumption, low profit. due to the productio

21、n technology is mature, abroad in the early construction device using this method, in our country is still widely used. in 1973, halcon scientific development corporation obtained the carbonylation of methyl acetate to acetic anhydride production of patent. in 1983, the company cooperates with ameri

22、can eastman-kodak company built up the first set of the carbonylation synthesis of acetic anhydride production device. celanese company also has this technology. the production process is as follows: the first is the methanol and acetic acid in sulfuric acid under the action of catalyst to generate

23、methyl acetate, the reaction pressure is normal pressure, reaction temperature of 65-85 c, the acetic acid conversion rate of about 100%. then, methyl acetate and methanol and carbon monoxide in the methyl iodide and rhodium catalyst or nickel catalysts ( for rhodium catalyst catalytic activity of n

24、i catalyst is 10 times, so the industrial use of rhodium catalyst ) presence, for carbonylation reaction of acetic anhydride and acetic acid, cogeneration. the reaction pressure is about 2.55 mpa, reaction temperature 180 degrees celsius. the acetic acid / acetic acid ratio can be adjusted according

25、 to the requirement. reaction equation:ch3cooh+ch3oh - ch3cooch3+h2o;ch3cooch3+co ( ch3co ) 2o;ch3oh+co - ch3cooh. methyl acetate carbonylation with a short process, products of good quality, low consumption, less waste discharges etc., represents the advanced level of production technology of aceti

26、c anhydride. at present, the main foreign suppliers are used in the process of acetic anhydride. liquid phase process than gas phase process maturity. british bp company in halcon and monsanto synthesis of acetic anhydride carbonylation to acetic acid based on technology, the successful development

27、of the carbonylation of methanol and acetic anhydride - acetic acid process, and on 1987 implementation industrialization ( figure 1 ( omitted) ). gas phase carbonylation of hoechst company in 1986 developed, reaction temperature, 185-216 c, by heterogeneous supported catalysts. the catalyst is a pr

28、ecious metals rhodium, iridium, palladium or rubidium contained in silica, three two aluminum oxide, magnesium oxide, two oxide carrier, which showed the highest activity of rhodium. gas phase esterification reaction with liquid phase method are the same, and liquid phase carbonylation carbonylation

29、 are similar. the difference is: the liquid phase carbonylation of methyl acetate in liquid phase carbonylation reaction; and the gas phase carbonylation reactions in the gas phase, gas phase process were removed from the reaction liquid catalyst recovery. gas phase process can reduce the loss of rh

30、odium, rhodium is fixed on the carrier without the accident was washed out in the solution. gas phase process in terms of investment is better than that of liquid phase process, but the project cost is higher. in 2003, dan group of jiangsu, chinese academy of sciences and beijing university three ho

31、mes, built up the first set of acetic anhydride carbonylation synthesis device, device dimensions is 20000 t / a acetic anhydride . the device can also adjust the production of methyl acetate by lanzhou petrochemical design institute, engineering general contracting and design, production of acetic

32、anhydride purity of the product reached more than 99.5%, more than 99.9% of methyl acetate. a ton of acetic anhydride consumption quota for methanol acetic acid 0.353 t, 0.604t, co for 0.340t, z catalyst 0.44, steam 4.2 t, 147 t water, electric 167kwh, instrument air 300m3. device operation practice

33、 proves, developed by china in this set of acetic anhydride production process is reliable. acetic anhydride carbonylation synthesis process, reactor by esterification and the carbonylation reactor, methanol and acetic acid in the esterification reactor to generate methyl acetate, methyl acetate in

34、carbonylation reactor and co synthesis of acetic anhydride. because the process of catalyst in water, generation acetic anhydride - at the same time, also generates a part of acetic acid. the processes for the production of acetic anhydride mainly, main raw material for co and methanol, acetic acid.

35、 in addition, the process also can directly use the raw materials of methanol and co in the carbonylation reactor in response to acetic acid, without esterification device. therefore, the process can be based on market demand for acetic acid, methyl acetate and acetic anhydride products switch. by c

36、arbonylation catalyst technology is the most important, institute of chemistry chinese academy of sciences after years of research and development and development of the domestic catalyst - multidentate ji ji heterozygous rhodium complexes catalyst. and the united states monsanto developed catalyst,

37、 the catalyst has a water content of less. from jiangsu, the dan group use, reaction conditions and catalyst abroad basically the same ( reaction pressure 3-6mpa, temperature 160-200 c ), an ideal application. in addition to using rhodium catalyst, the carbonylation synthesis of acetic anhydride pro

38、cess can also be used for other metal catalysts. although the rhodium catalyst catalytic activity and selectivity for the best, but there are expensive, shortage of resources, recycling costs higher shortcoming. therefore, many companies have shifted their attention to non noble metal catalysts, whi

39、ch are mainly i a iii a b or b, vi, viii non-noble metals. among them, nickel catalyst in the reaction conditions such as mild and catalytic properties are obviously superior to other non-noble metal, is a kind of the most development prospect of non noble metal catalysts. vinyl ketone and carbonyl

40、synthesis process is the production of acetic anhydride used method. from the contrast can be seen in table 1, ketene process is relatively complex, the product quality is low, the energy consumption is relatively high, high cost, pollution, heavy, small scale. 醋酐生產(chǎn)工藝 醋酐為無色易揮發(fā)，具有強(qiáng)烈刺激性氣味和腐蝕性液體。學(xué)名乙酸酐，

41、分子式為c4h6o3，閃點(diǎn)64.4。密度1.082 0g/cm3。熔點(diǎn)-74.13。沸點(diǎn)138.63。折射率nd 1.390。20粘度0.91 mpa?s。自燃點(diǎn)388.9。溶于冷水，在熱水中分解成醋酸，與乙醇生成乙酸乙酯。溶于氯仿、乙醚和苯。有毒，對(duì)眼及粘膜具有強(qiáng)烈的刺激性，質(zhì)量濃度為0.36 mg/m3時(shí)即對(duì)眼有刺激；0.18mg/m3時(shí)，就能改變?nèi)说哪X電圖象，還能引起細(xì)胞組織蛋白質(zhì)變質(zhì)。其蒸氣刺激性更強(qiáng)，極易燒傷皮膚及眼睛，如經(jīng)常接觸會(huì)引起皮炎和慢性結(jié)膜炎。對(duì)大鼠經(jīng)口ld50為1780 mg/kg。當(dāng)濺及或粘附于皮膚時(shí)，要立即用清水或2%蘇打水沖洗，全身中毒時(shí)應(yīng)及時(shí)就醫(yī)診治。空氣中最高容

42、許體積分?jǐn)?shù)5l/l。 醋酐是國家鼓勵(lì)發(fā)展的基本有機(jī)化工原料，主要用于生產(chǎn)醋酸纖維素，其中二醋酸纖維素用于制造香煙過濾嘴和塑料，三醋酸纖維素是制造高級(jí)感光膠片的材料，還廣泛用于醫(yī)藥、染料、農(nóng)藥、軍工、香料、金屬拋光等行業(yè)。 醋酐是“易制毒”產(chǎn)品，醋酐的生產(chǎn)、經(jīng)營都要依法在公安機(jī)關(guān)備案取證，企業(yè)賣出的每一批商品都要進(jìn)行詳細(xì)的備案登記，并到公安機(jī)關(guān)備案。依據(jù)法律規(guī)定，賣給無證單位200 kg醋酐，將被判處3年有期徒刑。 工業(yè)化的醋酐生產(chǎn)工藝有三種：乙醛氧化法、乙烯酮法和醋酸甲酯羰基化。 乙醛氧化法技術(shù)來源為加拿大sha winigan化學(xué)公司。生產(chǎn)工藝如下：乙醛和氧在60、101 kpa或70、60

43、0-700kpa條件下進(jìn)行氧化反應(yīng)，用氧氣或空氣作氧化劑，以醋酸乙酯為溶劑，醋酸鈷為催化劑，醋酸銅為促進(jìn)劑。乙醛與氧氣(過量約1%-2%)反應(yīng)首先生成過氧醋酸，過氧醋酸再與乙醛反應(yīng)生成醋酐和醋酸。在此條件下，乙醛轉(zhuǎn)化率為95%，醋酐及醋酸產(chǎn)率的質(zhì)量比為56：44。醋酐的總收率為70%-75%。通過改變工藝條件，可以提高醋酐的產(chǎn)率。反應(yīng)方程式為： ch3cho+o2ch3coooh； ch3coooh+ch3choch3coooch(oh) ch3(單過氧醋酸酯)； ch3coooch(oh)ch3(ch3co)2o+h2o； ch3coooch(oh)ch32ch3cooh。 每噸醋酐消耗乙醛

44、1.165 t，標(biāo)準(zhǔn)狀態(tài)空氣2300 m3。乙醛氧化法流程簡單，工藝成熟，但腐蝕嚴(yán)重，消耗較高，已逐漸被淘汰。在國外已被醋酸甲酯羰基化和乙烯酮法所替代。我國上海化學(xué)試劑總廠這種裝置已經(jīng)處于停產(chǎn)狀態(tài)。 乙烯酮法按照原料不同又可以分為：醋酸法和丙酮法。 醋酸法技術(shù)來源為德國wacher化學(xué)公司。生產(chǎn)工藝如下：第一步，醋酸在700-750、10-20kpa的壓力及0.2%-0.3%磷酸三乙酯(按醋酸質(zhì)量計(jì))作催化劑的條件下，裂解脫水制成乙烯酮，醋酸轉(zhuǎn)化率約為85%-90%，對(duì)乙烯酮的選擇性(物質(zhì)的量計(jì))約為90%-95%。反應(yīng)方程式為： ch3coohch2=c=o+h2o+147 kj/mol。

45、第二步是液體乙酸吸收乙烯酮生成醋酐，經(jīng)精餾提純制得成品醋酐，乙烯酮的轉(zhuǎn)化率約100%。反應(yīng)方程式為： ch3cooh+ch2=c=o(ch3co)2o+62.8kj/mol。 該生產(chǎn)工藝是德國wacher化學(xué)公司開發(fā)成功的，并于1936年實(shí)現(xiàn)工業(yè)化?，F(xiàn)有兩種生產(chǎn)流程： 其一，為塔式流程。用4個(gè)填料塔進(jìn)行合成與分離。每噸醋酐的消耗定額為，醋酸1.35t，催化劑1.5-2kg，氨0.7-1.0kg，回收醋酸100-160kg。 其二，為液環(huán)泵流程。以液環(huán)泵為反應(yīng)及吸收設(shè)備。該流程十分簡單，正在取代塔式流程。每噸產(chǎn)品的消耗定額為，醋酸1.22 t，裂解率75%，合成收率96%。 生產(chǎn)工藝如下： 第一

46、步是丙酮在700-800、常壓、沒有催化劑的條件下進(jìn)行裂解反應(yīng)。反應(yīng)方程式為： ch3coch3ch2=c=o+ch4-79.53 kj/mol。 第二步是液體乙酸吸收乙烯酮生成醋酐。反應(yīng)方程式為： ch2=c=o+ch3cooh(ch3co)2o+62.8kj/mol。 但在相同規(guī)模下，丙酮法和醋酸法比較，丙酮法需要較大的裂解爐、吸收塔和洗滌塔，并增加了循環(huán)丙酮-水的蒸餾分離等輔助設(shè)備，項(xiàng)目建設(shè)費(fèi)用高。同時(shí)，丙酮法的生產(chǎn)成本也較高。 乙烯酮法相對(duì)乙醛氧化法和醋酸甲酯羰基化工藝來說，流程復(fù)雜，副反應(yīng)多，能耗較大，利潤較低。由于生產(chǎn)技術(shù)相當(dāng)成熟，在國外早期建設(shè)的裝置應(yīng)用該法，在我國仍普遍應(yīng)用。 1973年，halcon科學(xué)開發(fā)集團(tuán)公司取得了醋酸甲酯羰基化生產(chǎn)的醋酐的專利。1983年，該公司與美國eastman-kodak公司合作建成了第一套羰基合成醋酐生產(chǎn)裝置。cel