CN1151393A - 从溶剂中精馏分离不饱和羧酸的方法 - Google Patents
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- C07C51/42—Separation; Purification; Stabilisation; Use of additives
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- C07C57/02—Unsaturated compounds having carboxyl groups bound to acyclic carbon atoms with only carbon-to-carbon double bonds as unsaturation
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Abstract
在从溶剂中精馏分离合成反应后吸收在溶剂中的不饱和羧酸的方法中，将精馏简便地中断，并用碱性溶液冲洗。按规则的时间间隔进行中断。所用的碱性溶液是碱金属和/或碱土金属氢氧化物(优选NaOH、KOH、Ca(OH)2)或其无水氧化物的水溶液；也可使用碱性的极性有机溶剂(如胺类或酰胺类)。
Description
本发明涉及一种用精馏法从溶剂中分离合成反应后吸收在溶剂中的不饱和羧酸的方法。
目前，在工业上丙烯酸或甲基丙烯酸类不饱和羧酸主要由相应的烯烃、烷烃或不饱和醛经非均相气相催化氧化制备。目前使用的各种方法的区别主要是，进行氧化的方法以及分离在氧化法中不可避免要生成的副产物的工艺技术(DE-A1962431、DE-A2943707)的不同。在合成中，各方法的区别在于反应气体是否循环以及加入的惰性气体的类型。在精制中，区别主要在于来自反应器的目的产物热气体是吸收在低沸点溶剂中或是高沸点溶液中。所有这些方法有一共同点，即最后目的产物都必须用精馏的方法从吸收溶剂中分出。
为了避免在精馏过程中发生聚合，需使用稳定剂，如吩噻嗪(PTZ)、氢醌甲醚(MeHQ)或氢醌(HQ)。尽管如此，在相当长时间操作后，在精馏塔中也会出现聚合物，这样就迫使定期停工并花费很大劳力来清洗设备。这一清洗可按已知的方式用机械的方法或热氧化法进行。但是，它们是很费时的。
本发明的一个目的是提供这样一种方法，用这一方法可简便且可靠地除去聚合物，不需太多的时间。
我们发现，通过中断精馏、然后用碱性溶液冲洗精馏塔的方法可实现这一目的。所用的碱性溶液最好是碱金属和/或碱土金属氢氧化物(优选NaOH、KOH、Ca(OH)2)或其无水氧化物的水溶液。在这里溶于水中的这些化合物的浓度为0.01-30％(重)，优选0.5-10％(重)。根据本发明优选的实施方案，将基本上中性的碱金属或碱土金属盐按＞0∶1至2∶1比(中性盐与氢氧化物的重量比)加到碱性溶液中。为此特别适合的是硫酸盐、乙酸盐、草酸盐、碳酸盐、硫酸氢盐、碳酸氢盐或其他相应碱性化合物的盐。盐的加入使碱性溶液的溶剂性能进一步提高。
根据本发明另一实施方案，碱性的极性有机溶剂如胺类或酰胺类(优选乙酸胺，特别优选单乙酰胺(CH3CONH2)可用来代替碱性水溶液作为溶剂。另一可用于此的溶剂是单甲基乙酰胺(CH3CON(CH3)H)、二甲基乙酰胺(CH3CON(CH3)2)和二甲基甲酰胺(HCON(CH3)2)。
根据本发明进行冲洗的温度由所用溶剂的沸点决定，因为所有上述溶剂的溶剂效果随温度升高而增加。碱金属和碱土金属氢氧化物含水体系的最佳温度为＞80至约115℃(常压下)，优选90-110℃。对于所述的酰胺来说，在每一情况下最佳使用温度应低于相应物质沸点的10-1℃。
本发明的方法可在规则的时间间隔下进行或达到某一沉积物生成量后进行。在每一情况下，需要较短的精馏过程中断时间，特别地达到了相当简便和更加完全地除去聚合物沉积物的目的。
本发明的其他详细内容和优点可在下述实验实施例中找到。
当然，本发明方法完全可用于精馏法分离不饱和羧酸，例如用于粗甲基丙烯酸的纯化精馏，得到纯甲基丙烯酸。发现使用本发明的方法是特别有好处的，也就是在一定的时间间隔在可见的沉积物出现以前。用这一方法事实上一开始就阻止沉积物生成。
实验室实验得到如下结果
实验1(对比实验，根据现有技术)
一种Diphyl/丙烯酸混合物在玻璃塔中精馏(内径8cm，40块泡帽塔板)。混合物取自DE2136396中公开的方法操作的生产装置。
用吩噻嗪使回流稳定。238小时后，由于聚合物生成，塔出现液体回冲。使塔停止操作，先用热水冲洗6小时。结果：不能除去聚合物，必须随后用机械的方法除去。总的清洗时间为整整一个工作日。
实验2(根据本发明用碱冲洗)
步骤同实验1，在212小时后出现回冲，在92℃下，用5％(重)NaOH水溶液冲洗，可使聚合物在冲洗6小时后完全溶解。
实验3(根据本发明用碱/硫酸盐冲洗)
步骤同实验2，在254小时后出现回冲。在92℃下，用含有5％(重)NaOH和5％(重)Na2SO4的水溶液冲洗，仅在冲洗5小时后可使聚合物完全除去。
实验4(根据本发明用酰胺冲洗)
步骤同实验2，在205小时后出现回冲。在190℃下用单甲基乙酰胺冲洗6小时后，可使聚合物完全除去。
生产实验
然后将实验室获得的知识用于工业装置。实验在根据DE 2136396中公开的方法操作的丙烯酸装置中进行。这一方法可简单描述如下：
*丙烯和/或丙烯醛非均相气相催化氧化生成丙烯酸
*用高沸点溶剂逆流吸收的方法，从反应气体中分离出丙烯酸和一部分副产物
*用逆流吸收法使第一部分低沸点副产物和中沸点副产物分离
*用蒸馏法从高沸点溶剂中分离丙烯酸和低费点副产物和中沸点副产物。
溶剂循环回吸收塔。
在这一精制的末端安装的纯化塔有纯化的丙烯酸侧线出口。为了防止由于聚合物生产出现的回冲，以及为达到很长的操作时间，在操作10-70天，优选20-50天后，使塔短时间停工，以便根据本发明的方法进行冲洗，这样就确保了塔能很长时间可靠操作。塔停工的时间由生产量和其他参数决定。
根据本发明，用10％(重)NaOH水溶液在92℃下的冲洗可在8小时内结束。
用10％(重)NaOH水溶液加5％(重)Na2SO4(按NaOH溶液计)在92℃下进行的冲洗甚至可更迅速地完成，冲洗时间只需7小时，使用单甲基乙酰胺作溶剂的对比冲洗在92℃下同样需要7小时。
Claims (9)
1.一种从溶剂中精馏分离合成反应后吸收在溶剂中的不饱和羧酸的方法，该法包括中断精馏，并用碱性溶液冲洗精馏塔。
2.根据权利要求1的方法，其中按规则的时间间隔进行中断。
3.根据权利要求1或2的方法，其中所用的碱性溶液是碱金属和/或碱土金属氢氧化物(优选NaOH、KOH、Ca(OH)2)或其无水氧化物的水溶液。
4.根据权利要求3的方法，其中溶于水的碱性化合物的浓度为0.01-30％(重)，优选0.5-10％(重)。
5.根据权利要求1或2的方法，其中将中性碱金属或碱土金属盐按＞0∶1至2∶1(中性盐与氢氧化物的重量比)加到碱性溶液中。
6.根据权利要求5的方法，其中加入的中性盐是硫酸盐、乙酸盐、草酸盐、碳酸盐或其他相应碱性化合物的中性盐。
7.根据权利要求1或2的方法，其中洗冲在80-115℃，优选90-110℃和常压下进行。
8.根据权利要求1的方法，其中所用的碱性溶液是碱性极性有机溶剂。
9.根据权利要求8的方法，其中所用的有机溶剂是胺类或酰胺类，优选乙酰胺类，特别是单乙酰胺。
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19536179.2 | 1995-09-28 | ||
| DE19536179A DE19536179A1 (de) | 1995-09-28 | 1995-09-28 | Verfahren zur rektifikativen Abtrennung von ungesättigten Carbonsäuren aus Lösungsmitteln |
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| CN1151393A true CN1151393A (zh) | 1997-06-11 |
| CN1068578C CN1068578C (zh) | 2001-07-18 |
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| CN96113381A Expired - Fee Related CN1068578C (zh) | 1995-09-28 | 1996-09-25 | 从溶剂中精馏分离不饱和羧酸的方法 |
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| EP (1) | EP0765854B1 (zh) |
| JP (1) | JPH09110779A (zh) |
| KR (1) | KR100453791B1 (zh) |
| CN (1) | CN1068578C (zh) |
| CA (1) | CA2183673A1 (zh) |
| CZ (1) | CZ292498B6 (zh) |
| DE (2) | DE19536179A1 (zh) |
| DK (1) | DK0765854T3 (zh) |
| ES (1) | ES2175004T3 (zh) |
| MX (1) | MX9603731A (zh) |
| MY (1) | MY116551A (zh) |
| SG (1) | SG50765A1 (zh) |
| TW (1) | TW358088B (zh) |
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| US6723398B1 (en) * | 1999-11-01 | 2004-04-20 | Dow Global Technologies Inc. | Polymer blend and fabricated article made from diverse ethylene interpolymers |
| SG85160A1 (en) * | 1999-03-02 | 2001-12-19 | Nippon Catalytic Chem Ind | Method for production of (meth) acrylic acid and/or (meth) acrylic esters |
| US6722377B1 (en) * | 1999-08-27 | 2004-04-20 | Rohm And Haas Company | Process for cleaning reactors |
| DE10000854A1 (de) * | 2000-01-12 | 2001-07-19 | Basf Ag | Verfahren zum Reinigen von Trennkolonnen |
| US7275038B1 (en) * | 2000-08-18 | 2007-09-25 | The Crawford Group, Inc. | Web enabled business to business operating system for rental car services |
| DE10144490A1 (de) * | 2001-09-10 | 2003-03-27 | Basf Ag | Verfahren zur Herstellung von (Meth)acrylsäureestern |
| AU2002362718B2 (en) * | 2001-10-09 | 2008-09-18 | Mitsubishi Chemical Corporation | Process for production of (meth)acrylic compounds and method of distillation |
| DE10211273A1 (de) | 2002-03-13 | 2003-03-06 | Basf Ag | Verfahren zur Reinigung von Bodenkolonnen, die zur rektifikativen Behandlung von (Meth)acrylsäure und/oder deren Ester enthaltenden Flüssigkeiten verwendet worden waren |
| DE10237061A1 (de) * | 2002-08-09 | 2004-02-19 | Basf Ag | Verfahren zur Reinigung von Apparaten, in welchen(Meth)acrylsäure enthaltende organische Lösungsmittel behandelt und/oder erzeugt wurden |
| JP3971974B2 (ja) * | 2002-09-03 | 2007-09-05 | 三菱化学株式会社 | （メタ）アクリル酸類の製造方法 |
| US20040104108A1 (en) | 2002-12-03 | 2004-06-03 | Mason Robert Michael | High capacity purification of thermally unstable compounds |
| DE10347664A1 (de) | 2003-10-09 | 2004-12-02 | Basf Ag | Verfahren der rektifikativen Auftrennung einer Acrylsäure enthaltenden Flüssigkeit |
| US8652624B2 (en) | 2007-11-14 | 2014-02-18 | Dow Global Technologies Llc | Articles and methods of making the same |
| WO2010129795A1 (en) * | 2009-05-08 | 2010-11-11 | 3M Innovative Properties Company | Oral care method and kit |
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| US3157693A (en) * | 1959-03-05 | 1964-11-17 | Celanese Corp | Recovery of acrylic acid esters by water wahing and fractionation |
| US3470238A (en) * | 1964-11-06 | 1969-09-30 | Mitsubishi Petrochemical Co | Process for recovering acrylic and methacrylic ester |
| US3818079A (en) * | 1970-07-07 | 1974-06-18 | Japanese Geon Co Ltd | Method of preventing the polymerization of unsaturated carboxylic acid |
| DE2235326A1 (de) * | 1972-07-19 | 1974-02-07 | Degussa | Verfahren zur reinigung 1,2-ungesaettigter carbonsaeuren |
| JPH05310636A (ja) * | 1992-05-14 | 1993-11-22 | Idemitsu Petrochem Co Ltd | アクリル酸エステル又はメタクリル酸エステルの製造方法 |
| US5432925A (en) * | 1993-08-04 | 1995-07-11 | International Business Machines Corporation | System for providing a uniform external interface for an object oriented computing system |
| DE4335172A1 (de) * | 1993-10-15 | 1995-04-20 | Basf Ag | Verfahren zur Reinigung von Roh-(Meth)acrylsäure |
-
1995
- 1995-09-28 DE DE19536179A patent/DE19536179A1/de not_active Withdrawn
-
1996
- 1996-08-13 US US08/696,193 patent/US5728272A/en not_active Expired - Fee Related
- 1996-08-19 CA CA002183673A patent/CA2183673A1/en not_active Abandoned
- 1996-08-21 TW TW085110170A patent/TW358088B/zh active
- 1996-08-23 MY MYPI96003485A patent/MY116551A/en unknown
- 1996-08-29 MX MX9603731A patent/MX9603731A/es not_active IP Right Cessation
- 1996-09-12 KR KR1019960039436A patent/KR100453791B1/ko not_active IP Right Cessation
- 1996-09-18 CZ CZ19962735A patent/CZ292498B6/cs not_active IP Right Cessation
- 1996-09-24 JP JP8251799A patent/JPH09110779A/ja active Pending
- 1996-09-25 CN CN96113381A patent/CN1068578C/zh not_active Expired - Fee Related
- 1996-09-26 DE DE59609045T patent/DE59609045D1/de not_active Revoked
- 1996-09-26 ES ES96115457T patent/ES2175004T3/es not_active Expired - Lifetime
- 1996-09-26 DK DK96115457T patent/DK0765854T3/da active
- 1996-09-26 EP EP96115457A patent/EP0765854B1/de not_active Revoked
- 1996-09-27 SG SG1996010696A patent/SG50765A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| TW358088B (en) | 1999-05-11 |
| DE19536179A1 (de) | 1997-04-03 |
| JPH09110779A (ja) | 1997-04-28 |
| KR970015554A (ko) | 1997-04-28 |
| MX9603731A (es) | 1997-03-29 |
| EP0765854A1 (de) | 1997-04-02 |
| CZ273596A3 (cs) | 1998-05-13 |
| ES2175004T3 (es) | 2002-11-16 |
| SG50765A1 (en) | 1998-07-20 |
| CA2183673A1 (en) | 1997-03-29 |
| KR100453791B1 (ko) | 2005-01-31 |
| DE59609045D1 (de) | 2002-05-16 |
| CN1068578C (zh) | 2001-07-18 |
| CZ292498B6 (cs) | 2003-10-15 |
| DK0765854T3 (da) | 2002-06-17 |
| MY116551A (en) | 2004-02-28 |
| EP0765854B1 (de) | 2002-04-10 |
| US5728272A (en) | 1998-03-17 |
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