WO2007020192A2

WO2007020192A2 - Method for covering the demand for polymers i, up to at least 90 % of which containing acrylic acid, salts thereof and/or alkyl esters of the acrylic acid in manner that is a radically incorporated by polymerization

Info

Publication number: WO2007020192A2
Application number: PCT/EP2006/065008
Authority: WO
Inventors: Ulrich Hammon; Klaus Joachim MÜLLER-ENGEL; Ulrich JÄGER
Original assignee: Basf Aktiengesellschaft
Priority date: 2005-08-12
Filing date: 2006-08-03
Publication date: 2007-02-22
Also published as: TW200710103A; EP1915405A2; CA2617955A1; JP2009504826A; CN102015790A; KR20080034203A

Description

Process for covering the need for polymers I containing at least 90% of their weight acrylic acid, their salts and / or alkyl esters of acrylic acid radically polymerized ein¬

description

The present invention relates to a process for covering the need for polymers I which contain at least 90% of their weight acrylic acid whose salts and / or alkyl esters of acrylic acid in free-radically polymerized form, in at least one of the countries I from the group include the United States of America, Hong Kong, Singapore, South Korea, Taiwan, Indonesia, Thailand, Japan, China, Germany, England, France, Italy, Belgium, Netherlands, Sweden, Switzerland, Norway, Finland, Denmark, Canada, Poland, the Czech Republic, Romania, Bulgaria, Spain, India, Pakistan, Portugal, Austria and South Africa.

It is generally known that acrylic acid can be prepared by heterogeneously catalyzed partial gas phase oxidation of propylene and / or of propane with molecular oxygen over catalysts in the solid state (cf., for example, EP-A 731 077, EP-A 1 254 709, EP-A). A 1 192 987, EP-A 1 193 240, DE-A 198 35 247, EP-A 895 809, DE-A 101 01 695, EP-A 293 224, EP-A 1 106 598, EP-A 990 636 DE-A 10 2005 009 885, DE-A 10 2004 003 212, DE-A 10 2005 013 039, DE-A 10 2005 009 891, DE-A 10 2005 010 111 and DE-A 102 45 585). This also includes processes in which propane is partially dehydrogenated to give propylene in the first reaction stage and / or oxydehydrogenated, and the resulting propylene is subsequently partially oxidized in the presence of the remaining propane (cf.

DE-A 102 45 585 and literature cited in this document). It is furthermore known to esterify acrylic acid with alkanols, in particular C 1 -C 5 -alkanols, in particular the monohydric alkanols, to give alkyl esters (this term also encompasses hydroxyalkyl esters herein) (eg EP-A 677 506, EP-A 694 524, EP-A). A 984 918 and EP-A 609 127). The acrylic acid (if appropriate also its salts, for example its alkali metal and / or ammonium salts which are obtainable by neutralization of acrylic acid with the corresponding bases such as alkali metal hydroxide (eg KOH, NaOH) or ammonia) and / or their alkyl esters are then frequently converted to polymers I polymerized containing at least 90% of its weight acrylic acid, their salts and / or their alkyl esters (alkyl acrylates) polymerized in a free radical and are used for a variety of uses (eg as adhesives, as water superabsorbent resins or as a binder). Optionally, neutralization can also take place after the polymerization.

The aim is to produce both acrylic acid, its salts and their alkyl acrylates, as well as the polymers I as economically as possible. The usual procedure is that the raw material base for the propane and / or propylene, namely petroleum or its distillates and / or natural gas from the regions of their natural occurrence into the countries I is exported. There, from higher hydrocarbons contained in these raw materials by thermal cracking at elevated temperatures and possibly under pressure and optionally in the presence of steam ("steam cracking") or catalysts (eg hydrosilicates, "catalytic cracking") obtained mixtures of lower hydrocarbons, from which, as part of their distillative separation in so-called splinters, also isolates the propylene and propane contained in them in good purity. The propylene and / or propane thus obtained is then used in countries I and others for the production of acrylic acid. Demanding esterification and subsequent free-radical polymerization of acrylic acid (and, if appropriate, their salts, for example their alkali metal salts) and / or their alkyl esters to give polymers I forms the current procedure for meeting the demand for polymers I in countries I.

A disadvantage of this procedure is that in countries I there is a predominant need for propane and propylene for purposes other than acrylic acid production. Thus, the propylene is used with a multiple amount needed mainly for the production of polypropylene. Propane is mainly used for energy production. That is, only a relatively small amount of demand of propylene or propane is used in countries I for acrylic acid production. As a consequence, the acrylic acid raw material base in countries I is comparatively expensive.

It has therefore also been proposed to relocate the production of acrylic acid in one of those countries Il, although promoted oil and gas, but only very limited chemical processing.

As such countries Il come into consideration the People's Republic of Yemen, Oman, Libya, Bahrain, Qatar, Saudi Arabia, Iran, Iraq, United Arab Emirates, Egypt, Kuwait, Venezuela, Brazil, Mexico, Nigeria, Russia, Kazakhstan, Uzbekistan, Turk - Menistan, Algeria, Syria, Jordan and Yemen.

For example, in these countries in the context of the abovementioned extraction of raw materials as by-product raw propanes (containing besides propane at least one component other than propane) could be used directly for a direct oxidation for the production of acrylic acid. Alternatively, the propane could be partially dehydrogenated to propylene and subsequently the resulting propylene be further processed to acrylic acid. In both cases, it does not require a cracker. As a result of the essentially non-existent subsequent chemistry in countries II, propane and / or propylene available in this way would be extremely cost-effective. The same applies to propane and / or propylene produced in refinery crackers, which may be operated in these countries. In refinery crackers are comparatively heavy-boiling petroleum fractions have been converted into relatively low-boiling gasolines and (petroleum) middle distillates.

Acrylic acid produced in countries II in such a cost-effective manner could then be exported to country I and further processed in it to meet the demand for polymers I. However, a disadvantage of such a procedure is that acrylic acid has a pronounced tendency to undesired free-radical polymerization. A ship transport of acrylic acid from countries Il to countries I would normally be done through different climate zones. The acrylic acid to be transported is either exposed to very different temperatures or has to be transported in a thermostated manner in a complex manner. In any case, during transport it must contain added significant additions of polymerization inhibitors (this also applies to a transport of their esters or salts), which subsequently have a disruptive effect on the preparation of polymers I. In addition, acrylic acid in itself forms by condensation reaction with itself first dimeric Michael adducts and by condensation with the same Michael oligomers. These also have a disadvantageous effect in the preparation of polymers I.

The object of the present invention was therefore to provide a process for meeting the demand for polymers I in at least one of the countries I, which does not have the described disadvantages of the prior art processes.

Accordingly, a process to meet the need for polymers I containing at least 90% of their weight of acrylic acid and / or alkyl esters of acrylic acid in copolymerized form in at least one of the countries I from the group comprising the United States of America, Japan, South Korea, Taiwan, Indonesia, Thailand, China, Germany, England, France, Italy, Belgium, Netherlands, Sweden, Switzerland, Norway, Finland, Denmark, Canada, Poland, the Czech Republic, Romania, Bulgaria, Spain, India, Pakistan, Portugal, Austria and South Africa, characterized by the fact that in at least one of the countries Il selected from the group include the People's Republic of Yemen, Oman, Libya, Bahrain, Qatar, Saudi Arabia, Iran, Iraq, United Arab Emirates, Egypt, Kuwait , Venezuela, Brazil, Mexico, Nigeria, Russia, Kazakhstan, Uzbekistan, Turkmenistan, Algeria, Syria, Jordan, Malaysia and Yemen by heterogeneous ka tallowed partial oxidation of propylene and / or propane produces acrylic acid, this neutralized in the at least one country Il as required with a base to form a salt of acrylic acid or esterified with an alkanol, and thus produced acrylic acid, their salts and / or their alkyl esters in the at least one country II is polymerized free-radically to polymers I and subsequently polymerisation sat I, possibly also in a form neutralized with a base, exported to at least one of the countries I.

The advantage of the procedure according to the invention lies in the fact that the production of acrylic acid in at least one country II is particularly cost-effective, that the prices for the required for the production of acrylic acid raw materials propane and / or propylene are disproportionately low. A transport of the "acrylic acid" in the form of polymers I from countries II to countries I is then possible without any detriment to a transport of the acrylic acid itself.Accordingly, the need for polymers I in countries I can be more cost-effective As a method for the production of acrylic acid from propane and / or propylene in countries II, basically all known processes of the prior art according to the invention can be considered.

However, according to the invention, one of the methods as used e.g. in EP-A 731 077, DE-A 102 45 585, DE-A 10 2005 009 885, DE-A 10 2004 003 212, DE-A 10 2005 013 039, DE-A 10 2005 009 891 and in DE-A 10 2005 010 111 are described.

In this process, crude propane (which is understood as meaning propane which contains at least one analytically detectable constituent other than propane) in a first step comprises at least one partial dehydrogenation process selected from the group consisting of homogeneous dehydrogenation, heterogeneously catalyzed dehydrogenation and subjected to heterogeneously catalyzed oxydehydrogenation, wherein a propane and propylene-containing gas mixture 1 is produced.

From the gas mixture formed in the first step 1 or from a subset deselen with the same composition is then separated from the components contained therein, of propane and propylene, optionally an amount and / or converted into other compounds, wherein from the gas mixture 1 respectively a propane and propylene-containing gas mixture 1 'is produced, and in at least one further step, gas mixture 1 and / or gas mixture 1' as a constituent of a gas mixture 2 (in the simplest way, for example obtainable by adding the gas mixture 1 and / or gas mixture 1 ' molecular oxygen, air, or another mixture of molecular oxygen and inert gas is added, but the required oxygen may also have been added in advance in the production of the gas mixture 1) a heterogeneously catalyzed gas phase partial oxidation of gas mixture 1 and / or gas mixture Subjected 'contained propylene.

In the simplest variant, all the steps of the process according to the invention are carried out in a single reaction zone and on a catalyst layer located in the same. as described, for example, in EP-A 608838, EP-A 529853, DE-A 19835247, EP-A 895809, EP-A 1192987, DE-A 10029338, WO 99/03825, DE-A 10118814, DE -A10119933, EP-A 603836, DE-A 19832033, DE-A 19836359, EP-A 962253 and EP-A 1193240. From the resulting product gas mixture, the acrylic acid can then be separated off as described in WO 04089856 and unreacted propane and propylene can be recycled to the reaction zone.

Preferably, however, the various steps are carried out in more than one reaction zone, e.g. EP-A 938463, EP-A 117146, DE-A 3313573, GB-A 2118939, US-A 31611670, WO 01/96270, EP-A 731077, DE-A

A 19837520, DE-A 10245585, DE-A 102005009885, DE-A 102004003212, DE-A 10200501303, DE-A 102005013039, DE-A 102005009891 and DE-A 102005010111. The separation of the acrylic acid from the resulting product gas can also be carried out as described in these documents. The same applies to the recycling of unreacted propane and propylene.

The resulting and purely separated acrylic acid can be neutralized as required with a base to their salts (eg with a metal hydroxide, or with amines) or with mono- or polyhydric alkanols, which preferably have 1 to 8 carbon atoms and are advantageously monovalent, on the Way of a direct reaction to obtain the corresponding alkyl acrylates are esterified. Suitable esterification catalysts are, for example, sulfuric acid, organic sulfonic acids (for example p-toluenesulfonic acid, methanesulfonic acid, benzenesulfonic acid or dodecylbenzenesulfonic acid) or sulfonic acid ion exchangers. For example, the esterification can be carried out as described in DE-A 19604252, EP-A 784046, EP-A 781759, EP-A 790230 and EP-A

A 795536 described. Preferred esterification alkanols are methanol, ethanol, propanol, n-butanol, tert-butanol, sec-butanol and 2-ethylhexanol. Preferred bases are the alkali metal hydroxides, especially KOH and NaOH, and NH ₃ .

According to the invention, polymers I preferably have at least 95% of their weight, and very preferably at least 98% of their weight, of free-radical copolymerization of their salts and / or alkyl esters of acrylic acid. In this case, the acrylic acid can be copolymerized either as such or in the form of one of its salts, for example its alkali metal salts (eg Na and / or K salt). Of course, the polymers I may also have been partially or completely neutralized subsequently to their preparation by free-radical polymerization by means of NaOH and / or KOH and optionally with NH 3 (or with another base). Of course, it is also possible to neutralize with the corresponding carbonates or bicarbonates. That is, in principle, the radical polymerization and / or after completion of radical polymerization with, for example, alkali metal and / or ammonium hydroxide may be partially or fully neutralized in advance. Suitable superabsorbent polymers I are described, for example, in DE-A 10221202, DE-A 10221203 and in EP-A 1506153. As a rule, they contain no or at most in amounts of up to 10% by weight of esters of acrylic acid.

That is to say, they are normally polymers I which at least 90% or at least 95% of their weight contain acrylic acid and / or salts thereof (in particular their alkali metal and / or ammonium salts, preferably their Na salt) contain. To optimize the properties of the superabsorbers, it may be useful to use monoethylenically unsaturated comonomers which do not carry any acid group. These include nitriles such as acrylonitrile, methacrylonitrile, amides such as acrylamide and methacrylamide, N-vinyl amides such as N-vinylformamide, N-vinylacetamide and N-vinylpyrrolidone, vinyl esters of unsaturated C 1 -C 4 -carboxylic acids such as vinyl formate, vinyl acetate and vinyl propionate, but also esters of monoethylenically unsaturated C ₃ -C ₆ - carboxylic acids. Other suitable mono-ethylenically unsaturated comonomers free of acid groups are styrene and alkyl-substituted styrenes, such as ethylstyrene or tert-butylstyrene. Such co-monomers may very generally be constituents of polymers I.

Frequently, polymers I which are suitable as superabsorbents also contain copolymerized crosslinking comonomers in small amounts (generally from 0.01 to 3% by weight). Comonomers which have 2, 3, 4 or 5 ethylenically unsaturated double bonds in the molecule are, for example, suitable as such. Examples include divinylbenzene and allyl acrylate. As crosslinking compounds it is also possible for saturated or unsaturated polyfunctional compounds which have at least two (for example 2, 3, 4 or 5) functional groups which have a reactivity with respect to the carboxyl group of the acrylic acid or its salts (in particular its alkali metal salts). are complementary. However, suitable crosslinkers are also monoethylenically unsaturated compounds which, in addition to the ethylenically unsaturated double bond, have a further functional group which is complementary to carboxyl groups.

Examples of these are hydroxyalkyl acrylates and hydroxyalkyl methacrylates. Also suitable as crosslinkers are polymers having a multiplicity of such complementary functional groups.

Suitable initiators for the preparation of polymers I are, in particular, peroxo compounds, such as organic peroxides, organic hydroperoxides, hydrogen peroxide, persulfates, perborates, azo compounds and redox initiator systems. The production of a superabsorber can also include internal postcrosslinking. For this purpose, the free-radically produced polymer is reacted in advance of its drying with compounds which have at least two opposite carboxyl groups or -COO ^Θ groups have reactive groups. This reaction can be carried out at room temperature or at elevated temperatures up to 22O ⁰ C. Polymers I should encompass such crosslinked polymers.

It should be noted at this point that all percent by weight, based on polymers I, always refer to "anhydrous" (i.e., completely dry) polymers I.

Of course, polymers I also include those polymers which, as described, have been obtained by free-radical polymerization, dried and optionally comminuted and then surface-crosslinked. For surface crosslinking, preference is given to using compounds which have at least two functional groups which can react with the functional groups, preferably the carboxyl or carboxylate groups, of the polymer with crosslinking. For this purpose, the postcrosslinkers, preferably in the form of an aqueous solution, are applied to the surface of the polymer particles. The aqueous solution may contain water-miscible organic solvents. Suitable postcrosslinking agents are, for example, di- or polyglycidyl compounds, diols and polyols, and polyamines and polyamidoamines. The application of the crosslinker solution is preferably carried out by spraying a solution of the crosslinker.

Otherwise, the preparation of water superabsorbent polymers I can proceed as in the already cited prior art. The preparation of superabsorbent polymers I is described moreover in "Modern Superabsorbent Polymer Technology", edited by FL Buchholz and AT Graham, Wiley-VCH (1998), and in the specifications EP-A 445619, DE-A 19846413, WO-A 01/38402, DE-A 3825366, US-A 6241928, EP-A 457660, WO-A 02/94328, EP-A 955086 and WO-A 02/94329, as in the state cited in these documents of the technique.

Incidentally, polymers I can generally be prepared by free-radical substance, solution, emulsion (especially aqueous) and suspension polymerization. These methods are known per se to the person skilled in the art and e.g. in DE-A 19602391 and WO 9727222. As a rule, the export of polymer material I will take place in at least one of the countries I by ship. In principle, however, a transport as air freight or in rail or road transport is possible. The transport of the polymers I can be carried out in bulk, as a solution, as an aqueous emulsion or as an aqueous suspension.

In a similar manner as in the method according to the invention can also be used to meet the demand for polymers which are mainly composed of acrylonitrile, or of methacrylonitrile, or esters of methacrylic acid, proceed. That is, the partial oxidation or partial oxidation of the corresponding precursors Fermentation, including optionally appropriate subsequent neutralization or esterification, as well as the polymerization in countries II and the resulting polymer is transferred to countries I.

Claims

claims

1. A method for meeting the need for polymers I, the at least 90% of their weight acrylic acid, their salts and / or alkyl esters of acrylic acid radically copolymerized in at least one of the countries I from the

Group comprising the United States of America, Japan, Hong Kong, Singapore, South Korea, Taiwan, Indonesia, Thailand, China, Germany, England, France, Italy, Belgium, Netherlands, Sweden, Switzerland, Norway, Finland, Denmark, Canada, Poland, the Czech Republic, Romania, Bulgaria, Spain, India, Pakistan, Portugal, Austria and South Africa, characterized by the fact that in at least one of the countries II selected from the group comprising the People's Republic of Yemen, Oman, Libya, Bahrain, Qatar, Saudi Arabia, Iran, Iraq, United Arab Emirates, Egypt, Kuwait, Venezuela, Brazil, Mexico, Nigeria, Russia, Kazakhstan, Uzbekistan, Turkmenistan, Algeria, Syria, Jordan, Malaysia and Yemen by heterogeneously catalyzed partial oxidation of propylene and or propane produces acrylic acid, these neutralized in the at least one country Il as required with a base to form a salt of acrylic acid or with an alkanol ver estert, and thus produced acrylic acid, whose salts and / or their alkyl esters in the at least one country II radically polymerized to polymers I and then so produced polymer I, optionally also in a subsequently neutralized with a base form, in at least one of the countries I exported.

2. The method according to claim 1, characterized in that the polymer I contains at least 95% of its weight of acrylic acid, their salts and / or alkyl esters of acrylic acid ein¬ free-radical polymerized.

3. The method according to claim 1, characterized in that the polymer I contains at least 90% of its weight acrylic acid and / or their salts copolymerized in a free-radically.

4. The method according to claim 1, characterized in that the polymer I contains at least 95% of its weight acrylic acid and / or their salts copolymerized in a free-radically.

5. The method according to any one of claims 1 to 4, characterized in that the method for the production of acrylic acid is a heterogeneously catalyzed partial oxidation of propylene.

6. The method according to claim 5, characterized in that it starts from crude propane, which in a first step at least one partial dehydrogenation process selected from the group comprising the homogeneous dehydrogenation, the heterogeneously catalyzed dehydrogenation and subjected to the heterogeneously catalyzed oxydehydrogenation to produce a propane and propylene-containing gas mixture 1, of this or a subset thereof of the same composition is then optionally separated from the constituents other than propane and propylene contained therein an amount and / or converted into other compounds, wherein in each case a propane and propylene-containing gas mixture 1 'is produced from the gas mixture 1, and then in at least one further step gas mixture 1 and / or gas mixture 1' as part of a gas mixture 2 of a heterogeneously catalyzed gas phases -

Partial oxidation of in the gas mixture 1 and / or gas mixture 1 'contained propylene subjected.