SYNTHESIS OF COMMERCIALLY SUITABLE POLYETHER POLYOLS FOR THE POLYURETHANE INDUSTRY BY POLYMERIZATION OF MULTIFUNCTIONAL ALCOHOLS

Description

DESCRIPTION of the industrial invention entitled: “SYNTHESIS OF COMMERCIALLY SUITABLE POLYETHER POLYOLS FOR THE POLYURETHANE INDUSTRY BY POLYMERIZATION “PRODUCTION OF MULTIFUNCTIONAL ALCOHOLS” By: COIMSpA - INDUSTRIAL ORGANIC CHEMISTRY MILANESE, Italian nationality, Via delle Azalee 19, 20090 Buccinasco (MI) Designated Inventors: BELLONI Nicolas, LURAGHI Andrea Filed on: July 30, 2024 *** DESCRIPTION The present invention relates to a pro- yield for the synthesis of suitable polyether polyols for the preparation of polyurethane by polymer- production of polyfunctional alcohols. Polyether polyols are a raw material of commercial interest for their chemical properties physical; they have broad applications and can be used, for example, as precursors of polyu- they are net. In the polyurethane industry, polyols, and in particular the polyether polyols, are the compo- main ingredient for polyurethane production. The hydroxyl groups of polyols react with the isocyanates forming the urethane bond and thus giving origin to polyurethanes. Depending on the type of application final cation, it is necessary to formulate the polyurethane with the most suitable polyol. For this reason it is essential for the polyurethane market to have an ever-widening choice of polyether polyols so as to be able to satisfy all the requests national, even the most demanding ones in terms of performance. In particular, it is desirable and preferable that These polyether polyols have the following characteristics: - purity: typically it must be greater than or equal to at 99.5%, - residual K content: typically must be less than 1 ppm, - residual Na content: typically must be less than 1 ppm, - residual Fe content: typically must be less than 5 ppm, - residual water content: typically must be evenings less than 0.050%, - pH: typically should be between 4.5 and 7.5, preferably between 5.0 and 7.0, - color: typically must be less than 50 Hz, preferably less than 35 Hz, more prefe- significantly lower than 10 Hz. In particular, the term "color" here used lized refers to the existence of vi- color sible that can be quantified by using of a spectrophotometer or colorimeter, using wavelengths of about 400-800 nm, and compare rinsing it with pure water (reference: 0 Hz). The color value is assigned according to the scale Hazen. Current synthesis methods: Synthesis of polyether polyols by polymerization ring-opening Ring-opening polymerization is the production method most used for the production tion of polyether polyols. The most polyethers polyols used are those that can be synthesized produced by ring-opening polymerization of the corresponding cyclic ethers, such as polyethylene glycol (PEG) which is obtained from ethylene oxide, the polypropylene glycol (PPG) that is obtained from propylene oxide and polytetrahydrofuran (PTHF or PTMEG) which is obtained by opening the tetrahydrofuran. The ring-opening reaction of ethers cyclics such as ethylene oxide and propylene oxide can occur through acid catalysis or ba- catalysis physics. The properties and composition of polyether resulting polyol can be controlled va- returning the ratio between ethylene oxide and oxide of propylene and using polyfunctional alcohols nali as a reaction starter. Another cyclic ether usable for the synthesis of polyether polyols is tetrahydrofuran which, again through polymerization catalyzed ring-opening reaction, allows to obtain polytetrahydrofuran. The polyether polyols obtained from these pro- cesses must be subjected to refining and pu- retrieval to remove any impurities. Although the products obtained with this technology are suitable in its use in polyurethane synthesis, the synthesis of polyether polyols by polymerization ring aperture action has limitations. In fact, it is not possible to obtain polyether polyols formed by monomers with 5 or more methylene units since the cyclic ethers to be used as precur- are extremely stable. This technology, therefore, it allows you to obtain a limited number of polyether polyols failing to cover all the performance requirements of the polyurethane industry tano. Synthesis of polyether polyols by polycondensation acid-catalyzed Polymerization of polyfunctional alcohols is a reaction that leads to the formation of a chain polymeric, or a macromolecule, formed by repeating units derived from the starting monomers. The starting monomers are polyfunctional alcohols. The reaction that occurs is also called polycondensation- tion and produces water as a byproduct. Current technology for the synthesis of polye- three polyols by catalytic polycondensation acid of polyfunctional alcohols (glycols) is a pro- process that allows the synthesis of polyether polyols with extremely interesting features for the world of polyurethane, but it has some limitations tions as the products obtained have indices of color and purity not suitable for this type of application cation. Over the years, various methods have been studied to improve the color of the obtained polyether polyols with this technology, and they all include the purifi- polyol cation or glycol pretreatment before the polycondensation reaction. In US patent 6,235,948 a pro- pre-polymerization process for the removal of impurities from the starting polyfunctional alcohol (which lead to increased color) through the use of ion exchange resins. In US Patent 7,294,746 post-polymerization treatment methods are described. treatment with adsorbents such as carbon black. En- both pre- and post-treatment methods added- there are steps in the process to produce a polymer commercially acceptable. Technologies have also been developed to mo- to modify the reaction conditions and control the color of the product. For example, the application for bre- US 2005 / 272911 discloses control methods of the formation of color by carrying out the reaction of polycondensation in the presence of a catalyst composed of an acid and a base. Or, WO 2011 / 041348 A2 describes a process where ag- a base is added during the reaction to obtain a color-reduced polyol. In both cases the ag- addition of a base reduces catalytic activity of the acid and at the same time leads to the presence + of unwanted ions in the final polyol (such as Na or + K ) which make the polyol unusable for the polyurethane synthesis. Metal ions give in- important interactions with subsequent processes of the polyurethane industry and consequently the need need for further steps to purify the product. US 2008 / 242830 A1 describes a process for the production of polyether polyols in the form of po- methylene ether glycols by polycondensation tion in the presence of at least one acid catalyst, where the resulting polyether polyols exhibit a reduced color; in a first phase, the polyether po- liol is prepared from 1,3-propane diol in the presence of an acid catalyst; subsequently, the polye- The polyol thus obtained is treated with an agent reducing agent to form a hydride to decrease the coloring of polyether polyol. The document does not mention the use of an acid oxidizing agent and a reducing acid in the reaction of polycondensation. Another technology that exploits polycondensation sation of polyfunctional alcohols is the one described in the patent EP 3 792 296 A2 which exploits the combi- nation of a BrØnsted acid with a base of BrØnsted to form the catalyst, a pro-salt ionic. The polyether polyols produced with this technology, however, do not have the required characteristics is from the polyurethane industry. The color of the pro- reduced is high and the ionic protic salt re- It is extremely difficult to remove from the po- liolo. The primary purpose of this invention is that of providing a procedure that allows the production of different types of polyethers po- lioli, suitable for the polyurethane industry, with a effective production process and without the need for post-synthesis treatments. In this context, a specific purpose of the in- invention is to provide a process that prevents partial degradation (oxidation) of the raw materials and the consequent increase in color of the product. Summary of the invention In order to achieve the above-mentioned purposes, constitutes an object of the present invention a process for the synthesis of polyether polyols me- acid-catalyzed polycondensation of alcohols multifunctional having the defined characteristics in the following claims, which constitute integral and integral part of this description tion. Another object of the invention lies in the use of a combination of acids, as a mixture catalytic, for the synthesis of polyether polyols, me- diante condensation of polyfunctional alcohols, of a catalytic mixture of acids comprising at least one oxidizing acid and at least one reducing acid. This type of catalysis allows to obtain polye- polyols, from polyfunctional alcohols, commercial- mind suitable for the polyurethane industry without need to carry out further treatments purpose of reducing color. The polyether obtained can be a homo- polymer or a copolymer, with distribution of mo- random or block names. The description also describes a polyether polyol obtainable by the process according to the invention and having, following the reaction of polycondensation, color below 50 Hz, pre- preferably lower than 35 Hz, more preferably less than 10 Hz, in the absence of further treatments minds for color reduction.re to Detailed description of the invention Polyether polyols suitable for the preparation of polyurethane to which the invention refers are polyether polyols, obtained by polycondensation of at least one or more di- or poly-functional alcohols, with particular specifications of purity and color, which make them usable as precursors for manu- polyurethane facts. These polyether polyols can they can therefore be used for numerous applica- tions such as: polyurethane for footwear, polyurethane for flexible foams, thermoplastic polyurethane, casting polyurethane, polyurethane adhesives, ade- hot-melt polyurethane, polyurethane for fake leather and polyurethane ink net The mixture of monomers, formed by one or more polyfunctional alcohols, is reacted in con- polycondensation conditions thanks to a mixture of at least one oxidizing acid and at least one oxidizing acid leader. The term polyfunctional alcohols refers to to molecules containing 2 or more functional groups hydroxylic (-OH) capable of giving po- reaction condensation. Polyfunctional alcohols can be (but are not limited to) monoethylene glycol- nicotine, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, glycol dipropylene, 2,2-dimethylpropanol, 1,4-butane- diol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonan- diol, 1,10-decanediol, 1,11-undecanediol, 1,12-do- decanediol, 2-butyl-2-ethyl-1,3-propanediol, 1-n- propyl-2-ethyl-1,3-propanediol, 1-isopropyl-2,2-di- methyl-1,3-propanediol, glycol hydroxypivalate neopentyl, 2-methyl-1,3-propanediol, 3-methyl-1,5- pentadiol, 1,3-butylene glycol, cyclohexanedimetha- nol, isosorbide, glycerin, trimethylolpropane, pen- taerythritol, polyethylene glycol with PM between 200 and 10000, polypropylene glycol with PM included between 200 and 10000, capped polypropylene glycol ethylene oxide with PM between 200 and 10000, polytetrahydrofuran with PM between 200 and 10000, polytrimethylene ether glycol with PM between 200 and 10000 or mixtures of two or more of these. The polyfunctional alcohols just described are the monomers that will lead to the formation of the desired polyether polyol. According to the invention the catalytic mixture of acids is a mixture comprising at least one acid oxidizing agent and at least one reducing acid. This mi- The choice of acids is intended to promote the reaction of polycondensation while maintaining the low color. The molar ratio between oxidizing acids and acids reducing agents at the beginning of the polycondensation reaction sation can be between 0.3 and 1.5. Preferi- can probably be between 0.5 and 1.2. More pre- It can probably be between 0.6 and 1.0. The acids constituting the catalytic mixture can be added to the reaction monomers in various ways: already pre-mixed together or one at a time time in the glycolic mixture before the start of the polymer synthesis process, in acid sequence reducing-acid oxidizing or already premixed in different phases of the process, dosing the quantity of considered in aliquots during processing. The term “oxidizing acid” refers to results in an acid in which the non-metal has the number of the highest oxidation it can take. An acid oxidant is therefore a molecule, equipped with a group acid, capable of reducing itself, oxidizing other species. Oxidizing acids can be (but are not li- a): nitric acid, sulfuric acid, p-acid toluenesulfonic acid (as is or substituted), ben- zensulfonic acid (as is or substituted), methane- sulfonic acid, chlorosophlonic acid, tetrafluoroe- trifluoromethanesulfonic acid, trifluoromethanesulfonic acid, trifluoromethanesulfonic acid perfluorooctanesulfonic acid, chloric acid, perclo- rich, iodic acid, chromic acid, acid permanganate or a mixture of two or more of these you. The term “reducing acid” refers to a acid in which the non-metal has an oxidation number lower than the maximum it can assume. A reducing acid is therefore a molecule, equipped with an acidic group, capable of oxidizing by reducing other species. Reducing acids can be (but are not limited to): oxalic acid, ascorbate bico, nitrous acid, aqueous solutions of anhydride sulfurous (SO *7H O), sulfurous acid, sulfi- 2 2 hydrochloric acid, bromous acid, phosphorous acid, hypophosphorous acid sphorous acid, diphosphorous acid, chlorous acid, acid hypochlorous acid, boric acid or a mixture of the two or more of these. The acids constituting the catalytic mixture, solid whether liquid or not, they will dissolve into the mixture of monomers. This type of catalysis is called “homogeneous catalysis”. Homogeneous catalysis is extremely effective compared to other types of ca- talisi; the only contraindication is the need for remove the catalyst at the end of the process. Acid oxidizing catalyst combinations and preferred reducing acid catalyst com- they take: - sulfuric acid with hypophosphorous acid; - p-toluenesulfonic acid with phosphorous acid; - p-toluenesulfonic acid with hypophosphorous acid; - p-toluenesulfonic acid with boric acid; - benzenesulfonic acid with phosphorous acid; - benzenesulfonic acid with hypophosphorous acid; - methanesulfonic acid with phosphorous acid; - methanesulfonic acid with hypophosphorous acid; - methanesulfonic acid with hypochlorous acid; - tetrafluoroethanesulfonic acid with hypophosphatase- exorbitant; - trifluoromethanesulfonic acid with sulfur- red The polycondensation reaction is carried out se- according to the conventional technique while keeping under pressure reaction of the reagents and with the removal of the water which is form as a result of polycondensation; the tempe- reaction rate, which is chosen according to the monomers used and the molecular weight that is wants to reach, can be between 160°C and 250°C. The pressure at which the synthesis may be slightly higher than the pres- atmospheric pressure (typically around +0.5 bar) in case of nitrogen stripping process or the reaction can be carried out under high vacuum (ti- typically between 30 mbar and 50 mbar of pressure residual). The reaction time is chosen according to the molecular weight, desired from time to time for the polyether polyol. Monomers can all be present up to from the beginning of the reaction or one or more monomers can be added at a later time. If only one monomer is present, a homopolymer, if there are more than one monomer present from the beginning you will get a random copolymer. If you adds a monomer different from the first in a second phase a block copolymer will be obtained. The acids constituting the catalytic mixture can be added to the reaction monomers in various ways: pre-mixed together, one at a time before the start of the process or individually in different phases of the process, dosing the quantity of considered all at once or in aliquots du- during processing. The reaction will end a once the desired molecular weight is reached. polyether polyol will not need further la- color reduction works: it will be only It is essential to remove the residues of the catalyst. to stop the reaction. This last process It is carried out by adding, at the end of the reaction, a adsorbent solid capable of removing residues of catalyst from the polyether polyol and performing finally a simple filtration to separate the phase liquid (polyether polyol) from the solid phase (ma- adsorbent material + free acid residue). Example A (Reference, without reducing acid) In a glass reactor, equipped with ag- Claisen capacitor and capacitor are added 8000 g of 1,6-hexanediol and 22g of methanesulfuric acid nico. The reagents are heated to a tempera- temperature equal to 180°C under inert gas flow. reaction is monitored in terms of molecular weight product color and texture. The molecular weight of the product is determined by titration of the –OH terminals while the color is determined via HACH Lange colorimeter on Hz scale. Test 1: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 118 0 10 398 146 16 1051 273 26 2056 441 Test 2: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 118 0 10 411 138 16 1072 271 26 2009 436 Test 3: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 118 0 10 423 144 16 1065 267 26 2088 439 Example B In a glass reactor, equipped with stirrer and Claisen condenser, they are added 8000g of 1,6 hexanediol and a mixture of acids were added formed from 22 g of methanesulfonic acid and 12 g of hypophosphorous acid. The reagents are heated to a temperature of 180°C under gas flow inert. The reaction is monitored in terms of molecular weight of the product and color. The molecular weight molecular weight of the product is determined by ti- removal of the –OH terminals while the color is determined by HACH Lange colorimeter on scale Hz. Test 1: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 118 0 10 523 0 16 1264 1 23 2011 5 Test 2: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 118 0 10 538 0 16 1302 0 23 2067 2 Test 3: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 118 0 10 492 0 16 1211 2 23 2001 6 Example C In a glass reactor, equipped with ag- Claisen capacitor and capacitor are added 6000g of 1,6 hexanediol, 2000g of monoethyl glycol- nico and a mixture of acids consisting of 20g of acid methanesulfonic acid and 11g of hypophosphorous acid. The rea- people are heated to a temperature equal to 200°C under an inert gas flow. The reaction is monitored in terms of molecular weight of the pro- product and color. The molecular weight of the product is determined by titration of the –OH terminals while the color is determined by color- HACH Lange meter on Hz scale. Test 1: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 96 0 10 514 0 18 1043 3 30 2037 8 Test 2: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 96 0 10 569 0 18 1173 0 30 2186 3 Test 3: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 96 0 10 542 0 18 1093 1 30 2085 7 Example D In a glass reactor, equipped with ag- Claisen capacitor and capacitor are added 8000g of 1,3-butylene glycol and a mixture of acids made up of 11g of methanesulfonic acid and 11g of hypochlorous. The reagents are heated to a temperature temperature equal to 220°C under inert gas flow. reaction is monitored in terms of molecular weight product color and texture. The molecular weight of the product is determined by titration of the –OH terminals while the color is determined via HACH Lange colorimeter on Hz scale. Test 1: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 90 0 8 284 0 16 563 0 22 997 2 Test 2: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 90 0 8 320 0 16 649 0 22 1063 0 Test 3: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 90 0 8 301 0 16 599 1 22 1026 3 Example E In a glass reactor, equipped with ag- Claisen capacitor and capacitor are added 7900g of neopentyl glycol, 100g of trimethylol- propane and a mixture of acids consisting of 18g of trifluoromethanesulfonic acid and 10g of sulfur- red. The reagents are heated to a tempera- temperature equal to 200°C under inert gas flow. reaction is monitored in terms of molecular weight product color and texture. The molecular weight of the product is determined by titration of the –OH terminals while the color is determined via HACH Lange colorimeter on Hz scale. Test 1: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 104 0 8 539 3 16 1011 8 24 1894 18 Test 2: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 104 0 8 487 3 16 942 9 24 1798 21 Test 3: Molecular Weight Time- Co- medium lore reaction (h) (g / mol) (Hz) 0 104 0 8 517 0 16 975 5 24 1856 11 Conclusions: As can be seen from the comparison between examples A and B, with the same monomers and synthesis conditions, the use of the catalytic mixture described by This invention allows to obtain colors of the final polyether polyol much lower and in line with the quality required for subsequent synthesis of polyurethane (which requires colors less than 50 Hz). Test Example A Example B N° Color (Hz) – a Color (Hz) – a end of reaction end of reaction 1 441 5 2 436 2 3 439 6 Examples B, C, D, and E demonstrate how the catalytic mixture described in the present invention the system is efficient even when using various types of types of monomers (glycols), both alone and in mix together, giving the opportunity to generate new types of polyether polyols to be used for the synthesis of polyurethanes. Example Monomers used B 1,6-hexanediol C 1,6-hexanediol + glycol monoethylene D 1,3-butylene glycol And neopentyl glycol + trimethylolpropane

Claims

1. Procedure for the synthesis of polyether polyols by acid-catalyzed polycondensation of polyfunctional alcohols, characterized by the fact that the polycondensation reaction is carried out with the use of a mixture of acid catalysts comprising at least one oxidizing acid and at least one reducing acid.

2. Process according to claim 1 characterized by the fact that the acid catalyst oxidant is chosen from the group consisting of acid nitric acid, sulfuric acid, p-toluenesulfonic acid (as is or substituted), benzenesulfonic acid (as is which or substituted), methanesulfonic acid, acid chlorosulfonic acid, tetrafluoroethanesulfonic acid, trifluoromethanesulfonic acid, acid perfluorooctanesulfonic acid, chloric acid, acid perchloric acid, iodic acid, chromic acid, acid permanganate or a mixture of two or more of these.

3. Process according to claim 1 or 2, characterized by the fact that the acid catalyst reducing agent is chosen from the group consisting of acid oxalic acid, ascorbic acid, nitrous acid, solutions aqueous sulfur dioxide (SO2*7H2O), acid sulfurous acid, hydrogen sulfide, bromous acid, acid phosphorous, hypophosphorous acid, diphosphorous acid, chlorous acid, hypochlorous acid, boric acid or a mixture of two or more of these.

4. Proceeding according to any of the claims 1 to 3, characterized by the fact that the molar ratio between oxidizing acids and reducing acids at the beginning of the reaction polycondensation is between 0.3 and 1.

5.

5. Proceeding according to any of the claims 1 to 4, characterized by the fact that the molar ratio between oxidizing acids and reducing acids at the beginning of the reaction polycondensation is between 0.5 and 1.

2.

6. Proceeding according to any of the claims 1 to 5, characterized by the fact that the molar ratio between oxidizing acids and reducing acids at the beginning of the reaction polycondensation is between 0.6 and 1.

0.

7. Proceeding according to any of the claims 1 to 6, characterized in that polyfunctional alcohol is chosen by the group that consists of monoethylene glycol, glycol diethylene, triethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, 2,2- dimethylpropanol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-butyl-2- ethyl-1,3-propanediol, 1-n-propyl-2-ethyl-1,3- propanediol, 1-isopropyl-2,2-dimethyl-1,3- propanediol, glycol hydroxypivalate neopentyl, 2-methyl-1,3-propanediol, 3-methyl-1,5- pentadiol, 1,3-butylene glycol, cyclohexanedimethanol, isosorbide, glycerin, trimethylolpropane, pentaerythritol, polyethylene glycol with PM between 200 and 10000, polypropylene glycol with PM between 200 and 10000, polypropylene glycol capped with oxide ethylene with PM between 200 and 10000, polytetrahydrofuran with PM between 200 and 10000, polytrimethylene ether glycol with PM between 200 and 10000 or from a mixture of two or more of these.

8. Proceeding according to any of the claims 1 to 7 characterized by the fact that the catalyst mixture is chosen by the group that consists of: - sulfuric acid with hypophosphorous acid; - p-toluenesulfonic acid with phosphorous acid; - p-toluenesulfonic acid with hypophosphorous acid; - p-toluenesulfonic acid with boric acid; - benzenesulfonic acid with phosphorous acid; - benzenesulfonic acid with hypophosphorous acid; - methanesulfonic acid with phosphorous acid; - methanesulfonic acid with hypophosphorous acid; - methanesulfonic acid with hypochlorous acid; - tetrafluoroethanesulfonic acid with hypophosphatase- exorbitant; - trifluoromethanesulfonic acid with sulfur- red 9. Process according to any of the claims indications 1 to 8, in which the polycondensation reaction sation is carried out with homogeneous catalysis at tempera- temperatures from 160°C to 250°C.

10. Use of a catalytic mixture comprising at least one oxidizing acid and at least one reducing acid cente, for the synthesis of polyether polyols, by means of polycondensation of polyfunctional alcohols.

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