CN114945617A - Process for producing short-chain polyether polyols - Google Patents

Abstract

The present invention relates to a process for producing short-chain polyether polyols comprising catalyzing the polymerization of a reaction mixture comprising an H-functional initiator and alkylene oxide monomers with an alkaline catalyst to form a crude alkaline short-chain polyether polyol, neutralizing the crude alkaline short-chain polyether polyol with a mineral acid to produce a crude acid-neutralized short-chain polyether polyol having an alkalinity of less than or equal to 0.60meq/kg, and purifying the acid-neutralized short-chain polyether polyol to produce a polyether polyol product having a hydroxyl value of from 100mg KOH/g to 1100mg KOH/g. The H-functional initiator may comprise 60 to 100% by weight of the plant-based H-functional initiator, based on the total weight of the H-functional initiator.

Description

Process for producing short-chain polyether polyols

Technical Field

The present specification relates generally to a method of producing short-chain polyether polyols using an H-functional initiator comprising plant-based glycerol. The present specification also relates to the use of such short-chain polyether polyols in the production of polyurethanes such as polyurethane foams.

Background

Polymeric polyols have many applications. For example, they can be reacted with isocyanates to produce polyurethanes, which are one of the most widely used polymeric materials in modern industrial fields. Polymeric polyols generally include two broad classes of polyols: polyether polyols and polyester polyols. Polyether polyols are typically prepared by reacting an epoxide with an initiator having an active hydrogen atom (i.e., an H-functional initiator). In contrast, polyester polyols are generally prepared by reacting polyfunctional carboxylic acids with polyfunctional hydroxy compounds.

Processes for producing polyether polyols typically employ various means for controlling the basicity of the final polyether polyol product. In particular, polyether polyol purification steps are generally aimed at reducing the alkali ion content until very low alkalinity levels (e.g., less than 5-10ppm) are reached. For example, polyether polyols are typically prepared by alkoxylation using a basic catalyst, followed by neutralization with an acid and filtration from the crude polyether polyol. However, a problem observed is that the alkalinity levels of certain short-chain polyether polyols prepared using glycerol H-functional initiators and alkaline catalysts may be inconsistent and are often too high. Furthermore, residual basic ions in the crude polyether polyol can adversely interfere with subsequent reactivity of the polyol, for example in the production of polyurethanes. It would therefore be desirable to provide a process for producing such short-chain polyether polyols which provides for maintaining a consistently low alkalinity level.

Drawings

Features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, various embodiments of the invention; and wherein:

FIG. 1 is a flow diagram of a process for producing short-chain polyether polyols;

FIG. 2 is a graph of the effect of different H-functional initiators on the basicity of different batches of short-chain polyether polyols; and

FIG. 3 is a graph of the trend of alkalinity of tallow-based versus vegetable-based H-functional initiators versus the final alkalinity of short-chain polyether polyols.

Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It should be understood, however, that the intention is not to limit the scope or particular invention embodiments.

Disclosure of Invention

In certain aspects, the present invention relates to a process for producing short-chain polyether polyols. The method may include catalyzing polymerization of a reaction mixture including an H-functional initiator and alkylene oxide monomers using an alkaline catalyst to form a crude alkaline short-chain polyether polyol, neutralizing the crude alkaline short-chain polyether polyol with a mineral acid to produce a crude acid-neutralized short-chain polyether polyol having an alkalinity level of less than or equal to 0.60meq/kg, and purifying the crude acid-neutralized short-chain polyether polyol to produce a short-chain polyether polyol product having a hydroxyl value of from 100mg KOH/g to 1100mg KOH/g. The H-functional initiator may comprise 60 to 100 wt% of the plant-based glycerol, based on the total weight of the H-functional initiator.

Detailed Description

Although the following detailed description contains many specifics for the purpose of illustration, one of ordinary skill in the art will appreciate that many variations and alterations to the following details can be made, and are considered to be included herein. Accordingly, the following embodiments are set forth without any loss of generality to, and without imposing limitations upon, any claims presented. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

As used in this specification, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a polyol" or "the/the polyol" may include a plurality of such polyols.

In the present application, "comprises", "comprising", "contains", "containing" and "having" and the like may have meanings given to them by the us patent law, and may mean "including", and the like, and are generally interpreted as open-ended terms. The terms "consisting of … …" or "consisting of … …" are closed-ended terms that include only the components, structures, steps, etc., that are recited in combination with these terms and in accordance with U.S. patent laws. "consisting essentially of … … (of) or" consisting essentially of … … (of) "generally has the meaning assigned to them by the U.S. patent laws. In particular, such terms are generally intended to be closed-ended terms, but are intended to include additional items, materials, components, steps or elements that do not materially affect the basic and novel characteristics or functions of the term with which it is used. For example, trace elements present in a composition that do not affect the properties or characteristics of the composition are permissible if they exist in the language "consisting essentially of", even if not expressly listed in the listing of terms following such terms. When open-ended terms such as "comprising" or "including" are used in this specification, it is to be understood that the language directly supporting "consisting essentially of … … (inclusive of) and" consisting of … … (inclusive of) "are to be interpreted as if explicitly stated, and vice versa.

The terms "first", "second", "third", "fourth", and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that any terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Similarly, if a method herein is recited as comprising a series of steps, the order of such steps presented herein is not necessarily the only order in which such steps may be performed, and certain recited steps may be omitted and/or certain other steps not recited herein may be added to the method.

As used herein, the term "substantially" refers to a complete or nearly complete range or degree of an action, feature, property, state, structure, item, or result. For example, an object that is "substantially" enclosed is intended to be completely enclosed or almost completely enclosed. In some cases, the exact degree of tolerance for deviation from absolute completeness may depend on the particular context. However, in general, an approximation will have the same overall result as if an absolute and a radical one were obtained. The use of "substantially" when used in a negative sense is also intended to refer to the complete or near complete absence of an action, feature, property, state, structure, item, or result. For example, a composition that is "substantially free" of particles will lack particles entirely, or nearly entirely, such that the effect will be the same as if the particles were entirely absent. In other words, a composition that is "substantially free" of an ingredient or element can still actually contain such an item so long as there is no measurable effect.

As used herein, the term "about" is used to provide flexibility to the numerical range endpoints by providing values that may be "slightly above" or "slightly below" the endpoints. Unless otherwise indicated, the use of the term "about" in reference to a particular number or numerical range should also be understood to provide support for such numerical terms or ranges without the term "about". For example, for convenience and brevity, a numerical range of "about 50 grams to about 80 grams" should also be understood to provide support for the range of "50 grams to 80 grams". Further, it should be understood that in the present specification, even if the term "about" is used, support is provided for the actual numerical value. For example, a recitation of "about" 30 should be interpreted to provide support not only for values slightly above 30 and slightly below 30, but also for the actual value 30. In some cases, "about" refers to an amount within 10% of a stated value. In other embodiments, "about" refers to an amount within 5% of a stated value.

As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.

For example, as used herein, the term "functionality" refers to the average number of reactive hydroxyl groups (-OH) present per molecule of the-OH functional material. In the preparation of polyurethane foams, hydroxyl groups react with isocyanate groups (-NCO) attached to isocyanate compounds. The term "hydroxyl number" refers to the number of reactive hydroxyl groups available for reaction and is expressed as milligrams of potassium hydroxide equivalent to the hydroxyl content of one gram of polyol (astm d 4274-16). The term "equivalent weight" refers to the weight of a compound divided by its valence. For polyols, the equivalent weight is the weight of the polyol combined with the isocyanate groups and can be calculated by dividing the molecular weight of the polyol by its functionality. The equivalent weight of the polyol can also be calculated by dividing 56, 100 by the hydroxyl number of the polyol — equivalent weight (g/equivalent) — (56.1x1000)/OH number.

Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. By way of illustration, a numerical range of "about 1 to about 5" should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range. Accordingly, included within this range of values are individual values, e.g., 2,3, and 4; and sub-ranges, such as 1-3, 2-4, and 3-5, etc.; and 1,2,3, 4, and 5 alone.

This same principle applies to ranges reciting only one numerical value as either a minimum or maximum value. Moreover, such an interpretation should apply regardless of the breadth of the range or the characteristics being recited.

Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least an implementation. Thus, the appearances of the phrase "in one embodiment" appearing in various places throughout the specification are not necessarily all referring to the same embodiment.

Example embodiments

The following provides a preliminary summary of embodiments of the invention, followed by a more detailed description of specific embodiments. This preliminary summary is intended to assist the reader in understanding the technical concepts more quickly, but is not intended to identify key or essential features thereof, nor is it intended to limit the scope of the claimed subject matter.

The methods of producing short-chain polyether polyols described herein provide various means for controlling the alkalinity throughout the production process to help provide consistently low alkalinity levels. For example, a method of producing a short-chain polyether polyol may include catalyzing polymerization of a reaction mixture including an H-functional initiator and an alkylene oxide monomer. When preparing the reaction mixture, care may be taken to select the H-functional initiator, in particular glycerol, to minimize the overall contribution of the H-functional initiator to the final alkalinity of the short-chain polyether polyol product. Otherwise, the production process may require additional time and cost to purify the short-chain polyether polyol product to achieve a suitable alkalinity level. For example, it has been found that vegetable-based (e.g., vegetable-based, nut-based, legume-based) glycerol may generally have a lower alkalinity level than tallow-based (i.e., animal fat-based) glycerol. Thus, in some embodiments, the plant-based glycerin contributes less to the final alkalinity of the short-chain polyether polyol product than the tallow-based glycerin.

In view of this, the process of the present invention may generally include plant-based glycerin in the reaction mixture to help minimize the initial alkalinity level in the reaction mixture and to help minimize the overall contribution of the H-functional initiator to the final alkalinity of the short-chain polyether polyol product. For simplicity, "glycerin" will be used herein to refer to "glycerin", and "glycerol", each of which may be used interchangeably herein. With this in mind, in some embodiments, the H-functional initiator can include from about 60% to about 100% by weight plant-based glycerol, based on the total weight of H-functional initiator in the reaction mixture. In some other embodiments, the H-functional initiator may comprise from about 80 wt% to about 100 wt%, from about 90 wt% to about 100 wt%, or from about 95 wt% to about 100 wt% of the plant-based glycerol, based on the total weight of H-functional initiator in the reaction mixture.

In some embodiments, the plant-based glycerol may be combined with a tallow-based H-functional initiator to minimize the initial alkalinity level of the reaction mixture. In other embodiments, the plant-based glycerol may be combined with additional plant-based H-functional initiators to minimize the initial alkalinity level of the reaction mixture. In a further example, the H-functional initiator may comprise a completely plant-based glycerol.

For example, plant-based H-functional initiators can be obtained from a variety of plant-based raw materials, such as various edible oils or mixtures thereof. Non-limiting examples of plant-based raw materials can include canola oil, cottonseed oil, peanut oil, linseed oil, coconut oil, linseed oil, corn oil, olive oil, palm kernel oil, palm oil, castor oil, rapeseed oil, sesame oil, soybean oil, sunflower oil, and the like, and combinations thereof. In some specific examples, the vegetable-based glycerin may be obtained from feedstocks including canola oil, coconut oil, corn oil, olive oil, palm oil, peanut oil, soybean oil, or combinations thereof.

A variety of H-functional initiators may be included in the reaction mixture, provided that at least a portion (e.g., at least 60 weight percent) of the H-functional initiators comprise plant-based glycerol. Non-limiting examples of H-functional initiators may include aliphatic or aromatic N-mono-, N-and N, N ' -dialkyl substituted diamines having 1 to 4 carbon atoms in the alkyl group, such as mono-and dialkyl substituted ethylene diamines, diethylene triamines, triethylene tetramine, 1, 5-pentanediamine, 1, 3-propanediamine, 1, 3-and/or 1, 4-butanediamine, 1,2-, 1,3-, 1,4-, 1, 5-and/or 1, 6-hexamethylenediamine, phenylenediamine, 2, 4-and 2, 6-toluenediamine, 4 ' -, 2, 4-and/or 2,2 ' -diaminodiphenylmethane, and the like, or combinations thereof. Other examples of H-functional initiators may include ethanolamine, diethanolamine, N-methyl-and N-ethyl alkanolamines, such as N-methyl-and N-ethyl-diethanolamine and triethanolamine, as well as ammonia, and the like, or combinations thereof. Other examples of H-functional initiators may include monofunctional compounds such as butyl carbitol, and polyfunctional compounds such as water, ethylene glycol, 1, 2-propylene glycol and/or trimethylene glycol, diethylene glycol, dipropylene glycol, 1, 4-butanediol, 1, 6-hexamethylene glycol, glycerol, trimethylolpropane, pentaerythritol, sorbitol, sucrose, and the like, or combinations thereof. The listed H-functional initiators can be used individually or as mixtures. Depending on the particular H-functional initiator used, the resulting short-chain polyether polyol may be a diol, triol, or other higher polyol. In some embodiments, the resulting short-chain polyether polyol may comprise a diol. In another embodiment, the resulting short-chain polyether polyol may be or include a triol.

Regardless of the particular H-functional initiator or combination of H-functional initiators employed in the reaction mixture, the overall alkalinity level of the H-functional initiator may be kept low. This minimizes the overall contribution of the H-functional initiator to the final basicity of the short-chain polyether polyol. In this regard, the level of alkalinity of the H-functional initiator may generally be less than or equal to 0.30 milliequivalents per kilogram (meq/kg). In some other embodiments, the H-functional initiator may have a basicity level of less than or equal to 0.25meq/kg, less than or equal to 0.20meq/kg, less than 0.15meq/kg, or less than or equal to 0.10 meq/kg. As previously mentioned, the use of H-functional initiators having alkalinity levels within these ranges may help to minimize the contribution of the H-functional initiator to the initial alkalinity of the reaction mixture and to the total alkalinity of the short-chain polyether polyol product. The basicity of the H-functional initiator may be measured according to ASTM D4662-15 or other similar methods.

In addition to the H-functional initiator, the reaction mixture may also include an alkylene oxide monomer. Non-limiting examples of alkylene oxide monomers can include styrene oxide, ethylene oxide, propylene oxide, butylene oxide, and the like, or combinations thereof. The alkylene oxide monomers may be used alone, in sequence or as a mixture of two or more thereof. In some specific embodiments, the alkylene oxide monomer may include from about 40 wt.% to about 100 wt.%, from about 60 wt.% to about 100 wt.%, or from about 80 wt.% to about 100 wt.% ethylene oxide, based on the total weight of the alkylene oxide monomer. In some other embodiments, the alkylene oxide monomer may include from about 40 wt% to about 100 wt%, from about 60 wt% to about 100 wt%, or from about 80 wt% to about 100 wt% of styrene oxide, based on the total weight of the alkylene oxide monomer. In some embodiments, the alkylene oxide monomers can include from about 40% to about 100%, from about 60% to about 100%, or from about 80% to about 100% by weight butylene oxide, based on the total weight of the alkylene oxide monomers. In some other embodiments, the alkylene oxide monomer may include from about 40 wt% to about 100 wt%, from about 60 wt% to about 100 wt%, or from about 80 wt% to about 100 wt% propylene oxide, based on the total weight of the alkylene oxide monomer. In other embodiments, the alkylene oxide monomer may include from about 90 wt% to about 100 wt%, or from about 95 wt% to about 100 wt% propylene oxide, based on the total weight of the alkylene oxide monomer.

The method of producing short-chain polyether polyols may also include catalyzing the polymerization of alkylene oxide monomers to form crude short-chain polyether polyols. The polymerization of alkylene oxide monomers can be catalyzed in a variety of ways. For example, catalyzing the alkoxylation of the alkylene oxide monomer can be performed by increasing the temperature of the reaction mixture, adding a basic catalyst to the reaction mixture, or a combination thereof. For example, in some cases, catalysis may be performed at elevated temperatures, or no catalyst may be used, or a reduced amount of catalyst may be used, which may allow for no filtration or minimize filtration processes. Thus, in some embodiments, a high temperature process may help control or minimize the alkalinity of the reaction mixture. Notably, achieving the desired reaction rate by using high temperature catalysis alone without the use of an alkaline catalyst may tend to have a temperature level that adversely affects the final short-chain polyether polyol product. Conversely, a large amount of basic catalyst may be added to the reaction mixture at a much lower temperature to provide greater thermal stability and an equivalent or faster reaction rate. The trade-off here may be increased viscosity of the reaction mixture and increased neutralization and filtration requirements of the production process.

Thus, although not absolutely required, the methods of producing short-chain polyether polyols described herein may generally include adding an alkaline catalyst to the reaction mixture at a temperature of from about 50 ℃ to about 125 ℃. In more detail, a variety of alkaline catalysts can be added to or included in the reaction mixture to catalyze the polymerization of alkylene oxide monomers to form crude alkaline short-chain polyether polyols. Non-limiting examples can include C1 to C4 alkali metal alkoxides, alkali metal hydroxides, and the like, or combinations thereof. The C1-C4 alkali metal alkoxide can include, for example, sodium methoxide, sodium ethoxide, potassium isopropoxide, sodium butoxide, etc., or a combination thereof. For example, the alkali metal hydroxide may include sodium hydroxide, potassium hydroxide, cesium hydroxide, strontium hydroxide, barium hydroxide, and the like, or combinations thereof. The alkali metal hydroxide can be used as a solid alkali metal hydroxide catalyst or an aqueous alkali metal hydroxide catalyst (e.g., from about 0 wt.% to about 50 wt.%, from about 5 wt.% to about 45 wt.%, or from about 10 wt.% to about 40 wt.% of an aqueous alkali metal hydroxide catalyst). Thus, in some embodiments, the basic catalyst may comprise from about 40 wt.% to about 100 wt.% of the alkali metal hydroxide (as a solid alkali metal hydroxide or an aqueous alkali metal hydroxide) and from about 0 wt.% to about 60 wt.% of the alkali metal hydroxide, based on the total weight of the basic catalyst. In some other embodiments, the basic catalyst may comprise from about 60 wt% to about 100 wt%, from about 80 wt% to about 100 wt%, from about 90 wt% to about 100 wt%, or from about 95 wt% to about 100 wt% of alkali metal hydroxide (as solid alkali metal hydroxide or aqueous alkali metal hydroxide), based on the total weight of the basic catalyst and any remaining amount of another basic catalyst. In some specific embodiments, the basic catalyst may comprise from about 40 wt% to about 100 wt% potassium hydroxide (as solid potassium hydroxide or an aqueous solution of potassium hydroxide) and from about 0 wt% to about 60 wt% of another basic catalyst, based on the total weight of the basic catalyst. In some other embodiments, the basic catalyst may comprise from about 60 wt% to about 100 wt%, from about 80 wt% to about 100 wt%, from about 90 wt% to about 100 wt%, or from about 95 wt% to about 100 wt% of potassium hydroxide (as solid potassium hydroxide or aqueous potassium hydroxide solution), based on the total weight of the basic catalyst and any remaining amount of another basic catalyst.

As noted above, since the basic catalyst is typically used in conjunction with higher temperatures, the amount of basic catalyst can be maintained at a concentration that reduces or minimizes the neutralization and filtration requirements. In some specific embodiments, the reaction mixture may include from about 0.01 wt% to about 1 wt% of the basic catalyst, based on the total weight of the reaction mixture. In some other embodiments, the reaction mixture may include from about 0.01 wt% to about 0.6 wt%, from about 0.05 wt% to about 0.8 wt%, or from about 0.08 wt% to about 1 wt% of the basic catalyst, based on the total weight of the reaction mixture. In some specific embodiments, the reaction mixture may include from about 0.05 wt% to about 0.5 wt% of the basic catalyst, based on the total weight of the reaction mixture.

The crude alkaline short-chain polyether polyol obtained by catalytic polymerization of an alkylene oxide monomer is neutralized with a mineral acid to produce a crude acid-neutralized short-chain polyether polyol. The amount of mineral acid added to the crude basic short-chain polyether polyol may vary depending on the amount of basic catalyst used to catalyze the alkoxylation reaction. Nevertheless, neutralizing the crude alkaline short-chain polyether polyol may include adding an amount of a mineral acid to obtain a crude acid-neutralized short-chain polyether polyol having an alkalinity level of less than or equal to 0.60 meq/kg. In some other embodiments, neutralizing the crude alkaline short-chain polyether polyol may include adding an amount of a mineral acid to obtain a crude acid-neutralized short-chain polyether polyol having an alkalinity level of less than or equal to 0.40meq/kg, less than or equal to 0.30meq/kg, less than or equal to 0.20meq/kg, or less than or equal to 0.10 meq/kg. The alkalinity value may be determined according to ASTM D6437 or other similar test methods. It is noteworthy that, although neutralization is performed prior to purification, measurement of the final basicity of the short-chain polyether polyol using ASTM D6437 is typically performed after purification.

Various inorganic acids may be used to neutralize the crude alkaline short-chain polyether polyol. Non-limiting examples of the inorganic acid may include hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, boric acid, and the like, or combinations thereof. The mineral acid may be concentrated or diluted as desired. In some embodiments, the mineral acid may have a concentration of about 5% to about 98% by weight in a suitable diluent (e.g., water). In some embodiments, the mineral acid may include hydrochloric acid. In some other embodiments, the inorganic acid may include phosphoric acid. In other embodiments, the mineral acid may include nitric acid. In other embodiments, the mineral acid may include boric acid. In other embodiments, the mineral acid may include sulfuric acid. In some specific embodiments, the mineral acid can include from about 60 wt% to about 100 wt% sulfuric acid (as dilute sulfuric acid or concentrated sulfuric acid) and from 0 wt% to 40 wt% of another neutralizing acid, based on the total weight of the mineral acid. In some other embodiments, the inorganic acid may include from about 80 wt% to about 100 wt%, from about 90 wt% to about 100 wt%, or from about 95 wt% to about 100 wt% sulfuric acid ((as dilute sulfuric acid or concentrated sulfuric acid) based on the total weight of the inorganic acid and any remaining amount of another neutralizing acid).

The amount of inorganic acid added to the reaction mixture to neutralize the basic catalyst may vary depending on the particular catalyst and its amount used in the reaction mixture. Generally, the amount of inorganic acid can be from about 90% to about 115% or from about 100% to about 110% of the theoretical amount of the corresponding acid required to completely neutralize the basic catalyst. In addition, neutralization can be carried out at various temperatures. In some specific embodiments, neutralization may be carried out at a temperature of about 50 ℃ to about 130 ℃.

In some embodiments, neutralizing may also include adding an adsorbent to the crude alkaline short-chain polyether polyol to adsorb alkaline catalyst ions (e.g., potassium ions in the case where potassium hydroxide is used as the alkaline catalyst). The adsorbent may typically have a high surface area (e.g., 100- ² /g) to help promote the adsorption efficiency of the catalyst ions. Non-limiting examples of adsorbents can include aluminum silicates such as montmorillonite, bentonite, activated fuller's earth, and the like, or combinations thereof. The adsorbent may also comprise magnesium silicate, for example

And so on. Any of these adsorbents or the like may be used alone or in combination to help neutralize the crude alkaline short-chain polyether polyol.

The crude acid neutralized short chain polyether polyol can be purified to produce a short chain polyether polyol product. Purification may include filtration, removal of water, or various addition steps to obtain the short-chain polyether polyol product. For example, in some cases, purification may include filtering the crude acid-neutralized polyether polyol. Filtration can help remove neutralized basic catalyst salt crystals, any added adsorbent, and the like.

In some other embodiments, the purification may include removing water from the crude acid neutralized short-chain polyether polyol. In some embodiments, the water may be removed by vacuum distillation or other suitable methods. Typically, the water removal may be performed to achieve a water amount of less than or equal to 0.1 wt% water, based on the total weight of the short chain polyether polyol product. In other embodiments, the amount of water may be reduced to less than or equal to 0.08 wt% water or 0.05 wt% water, based on the total weight of the short-chain polyether polyol product.

As mentioned above, the present process involves the production of short-chain polyether polyols. As used herein, a "short-chain" polyether polyol refers to a polyol having a hydroxyl number of about 100mg KOH/g to about 1100mg KOH/g, as determined according to ASTM D6342-12. Thus, purification of the crude acid neutralized short chain polyether polyol provides a short chain polyether polyol product having a hydroxyl number of from about 100mg KOH/g to about 1100mg KOH/g. In some other embodiments, the hydroxyl value of the short-chain polyether polyol product may be from about 100mg KOH/g to about 400mg KOH/g, from about 200mg KOH/g to about 600mg KOH/g, from about 400mg KOH/g to about 800mg KOH/g, or from about 600mg KOH/g to about 1100mg KOH/g. In some specific embodiments, the short-chain polyether polyol may have a hydroxyl value of about 100mg KOH/g to about 200mg KOH/g, about 400mg KOH/g to about 600mg KOH/g, or about 900mg KOH/g to about 1100mg KOH/g.

FIG. 1 depicts one embodiment of a method 100 for producing short-chain polyether polyols. The process 100 may include catalyzing 110, with a basic catalyst, polymerization of a reaction mixture including an H-functional initiator and alkylene oxide monomers to form a crude alkaline short-chain polyether polyol, the functional initiator including 60 wt% to 100 wt% vegetable-based glycerol, based on a total weight of the H-functional initiator. Further, the process 100 may include neutralizing 120 the crude alkaline short-chain polyether polyol with a mineral acid to produce a crude acid-neutralized short-chain polyether polyol having an alkalinity level of less than or equal to 0.60 meq/kg. The method 100 may also include purifying 130 the crude acid neutralized short chain polyether polyol to produce a short chain polyether polyol product having a hydroxyl value of from 100mg KOH/g to 1100mg KOH/g.

It is further noted that the short-chain polyether polyol products described herein may also be reacted with diisocyanates, polyisocyanates, or combinations thereof to produce rigid foams or other suitable polyurethane-based products. In such embodiments, any known organic isocyanate, modified isocyanate, or isocyanate-terminated prepolymer made from any known organic isocyanate may be used. Suitable organic isocyanates include aromatic, aliphatic, and cycloaliphatic polyisocyanates and combinations thereof. Useful isocyanates include: diisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 1, 6-hexamethylene diisocyanate, 1, 4-hexamethylene diisocyanate, 1, 3-cyclohexane diisocyanate, 1, 4-cyclohexane diisocyanate, isomers of hexahydrotolylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, 1, 5-naphthalene diisocyanate, 4 '-diphenylmethane diisocyanate, 2, 4' -diphenylmethane diisocyanate, 4 '-biphenyl diisocyanate, 3' -dimethoxy-4, 4 '-biphenyl diisocyanate and 3, 3' -dimethyldiphenylpropane-4, 4' -diisocyanate; triisocyanates such as 2,4, 6-toluene triisocyanate; and polyisocyanates such as 4,4 ' -dimethyl-diphenylmethane-2, 2 ', 5,5 ' -tetraisocyanate and polymethylene polyphenyl-polyisocyanates.

Undistilled or crude polyisocyanates may also be used. Crude toluene diisocyanate obtained by phosgenating a mixture of toluene diamines and crude diphenylmethane diisocyanate obtained by phosgenating crude diphenylmethane diamine (polymeric MDI) are examples of suitable crude polyisocyanates. Suitable undistilled or crude polyisocyanates are disclosed in U.S. patent No. 3,215,652.

Modified isocyanates are obtained by chemical reaction of diisocyanates and/or polyisocyanates. Useful modified isocyanates include, but are not limited to, those containing ester groups, urea groups, biuret groups, allophanate groups, carbodiimide groups, isocyanurate groups, uretdione groups and/or urethane groups. Examples of modified isocyanates include prepolymers containing NCO groups and having an NCO content of 25 to 35% by weight, for example 29 to 34% by weight, such as those based on polyether polyols or polyester polyols and diphenylmethane diisocyanate.

In some other embodiments, a blowing agent may be used to produce a polyurethane product (e.g., a rigid foam). Non-limiting examples of blowing agents can include physical blowing agents comprising HCFO, chemical blowing agents that generate carbon dioxide, and the like, or combinations thereof.

Suitable HCFOs include 1-chloro-3, 3, 3-trifluoropropene (HCFO-1233zd, E and/or Z isomers), 2-chloro-3, 3, 3-trifluoropropene (HCFO-1233xf), HCFO1223, 1, 2-dichloro-1, 2-difluoroethylene (E and/or Z isomers), 3, 3-dichloro-3-fluoropropene, 2-chloro-1, 1,1,4,4, 4-hexafluorobutene-2 (E and/or Z isomers), 2-chloro-1, 1,1,3,4,4, 4-heptafluorobutene-2 (E and/or Z isomers). In some embodiments, the boiling point of the HCFO at atmospheric pressure is at least-25 ℃, at least-20 ℃, or in some cases, at least-19 ℃ and 40 ℃ or less, e.g., 35 ℃ or less, or, in some cases, 33 ℃ or less. The boiling point of HCFO at atmospheric pressure may be, for example, -25 ℃ to 40 ℃, or-20 ℃ to 35 ℃, or-19 ℃ to 33 ℃.

In certain embodiments, one or more other physical blowing agents may be used, such as other halogenated blowing agents, e.g., CFCs, HCFCs, and/or HFCs, and/or hydrocarbon blowing agents, e.g., butane, n-pentane, cyclopentane, hexane, and/or isopentane (i.e., 2-methylbutane), among others. In some embodiments, carbon dioxide generating chemical blowing agents such as water and/or formic acid blocked amines may be used.

In certain embodiments, the blowing agent composition comprises HCFO and a carbon dioxide-yielding chemical blowing agent, such as water, wherein the HCFO and carbon dioxide-yielding chemical blowing agent are present in an amount of at least 90 wt.%, such as at least 95 wt.%, or, in some cases, at least 99 wt.%, based on the total weight of the blowing agent composition. In certain embodiments, the HCFO and carbon dioxide-producing chemical blowing agent are present in the blowing agent composition in a weight ratio of at least 2:1, such as at least 4:1, for example, from 4:1 to 10:1 or from 4:1 to 6: 1.

The blowing agent composition may, if desired, contain other physical blowing agents, such as (a) other Hydrofluoroolefins (HFOs) such as pentafluoropropane, tetrafluoropropene, 2,3,3, 3-tetrafluoropropene, 1,2,3, 3-tetrafluoropropene, trifluoropropene, tetrafluorobutene, pentafluorobutene, hexafluorobutene, heptafluorobutene, heptafluoropentene, octafluoropentene, and nonafluoropentene; (b) hydrofluorocarbon (c) hydrocarbons, such as any pentane isomers and butane isomers; (d) hydrofluoroethers (HFEs); (e) c1 to C5 alcohols, C1 to C4 aldehydes, C1 to C4 ketones, C1 to C4 ethers and diethers, and carbon dioxide. Specific examples of such blowing agents are described in U.S. patent application publication Nos. US 2014/0371338A 1 [0051] and [0053], the referenced portions of which are incorporated herein by reference.

Various other components may also be combined with the polyol to produce a suitable polyurethane-based product. Non-limiting examples may include surfactants, blowing catalysts, trimerization catalysts, gelling catalysts, colorants, antioxidants, flame retardants, stabilizers, fillers, and the like, or combinations thereof. Thus, the short-chain polyether polyols described herein may be used to produce a variety of polyurethane-based products.

In conjunction with the general description provided herein, the following provides some non-limiting, exemplary embodiments of a method of producing short-chain polyether polyols, as follows:

clause 1. a method of producing a short-chain polyether polyol, comprising: catalyzing polymerization of a reaction mixture comprising an H-functional initiator and alkylene oxide monomers with an alkaline catalyst to form a crude alkaline short-chain polyether polyol, the H-functional initiator comprising 60 to 100 wt% plant-based glycerol, based on the total weight of the H-functional initiator;

neutralizing the crude alkaline short-chain polyether polyol with an inorganic acid to prepare a crude acid-neutralized short-chain polyether polyol having an alkalinity of less than or equal to 0.60 meq/kg; and

purifying the crude acid neutralized short chain polyether polyol to produce a short chain polyether polyol product having a hydroxyl number of from 100mg KOH/g to 1100mg KOH/g.

Clause 2. the method of clause 1, wherein the alkylene oxide comprises from 80 to 100 weight percent propylene oxide based on the total weight of the alkylene oxide.

Clause 3. the method of clause 1 or clause 2, wherein the H-functional initiator comprises 95 to 100 weight percent plant-based glycerol, based on the total weight of the H-functional initiator.

Item 4. the method of any of items 1-3, wherein the vegetable-based glycerol is obtained from a feedstock comprising canola oil, coconut oil, corn oil, olive oil, palm oil, peanut oil, soybean oil, or a combination.

Clause 5. the method of any one of clauses 1-4, wherein the H-functional initiator has a basicity of less than or equal to 0.30 meq/kg.

Clause 6. the method of any one of clauses 1-5, wherein the basic catalyst comprises a C1-C4 alkali metal alkoxide, an alkali metal hydroxide, or a combination thereof.

Clause 7. the method of any one of clauses 1-6, wherein the basic catalyst comprises 60 to 100 weight percent potassium hydroxide, based on the total weight of the basic catalyst.

Clause 8. the method of any one of clauses 1-7, wherein the reaction mixture comprises 0.01 to 0.6 wt.% of the basic catalyst, based on the total weight of the reaction mixture.

Clause 9. the method of any one of clauses 1-8, wherein the inorganic acid comprises hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, boric acid, or a combination thereof.

Clause 10. the method of any one of clauses 1-9, wherein the mineral acid comprises 60 to 100 weight percent sulfuric acid, based on the total weight of the mineral acid.

Clause 11. the method of any one of clauses 1-10, wherein the crude acid neutralized short chain polyether polyol has an alkalinity of less than or equal to 0.40 meq/kg.

Clause 12. the method of any one of clauses 1-11, wherein neutralizing further comprises adding an adsorbent to the crude alkaline short-chain polyether polyol to adsorb alkaline catalyst ions.

Clause 13. the method of clause 12, wherein the adsorbent comprises aluminum silicate, magnesium silicate, or a combination thereof.

Clause 14. the method of any one of clauses 1-13, wherein purifying comprises filtering the crude acid neutralized short chain polyether polyol.

Clause 15. the method of any one of clauses 1-14, wherein purifying comprises removing water from the crude acid neutralized short chain polyether polyol to achieve an amount of water in the short chain polyether polyol product of less than or equal to 0.10 wt.% water, based on the total weight of the short chain polyether polyol product.

Clause 16. the method of any one of clauses 1-15, wherein the short-chain polyether polyol product has a hydroxyl number of from 400mg KOH/g to 600mg KOH/g.

Clause 17. the method of any one of clauses 1-15, wherein the short-chain polyether polyol product has a hydroxyl number of from 900 to 1100mg KOH/g.

Examples

Example 1 Effect of alkalinity of H-functional initiator

Many test batches of short-chain polyether polyol were prepared based on various H-functional initiators from different sources (vegetable-based and tallow-based) to determine the effect, if any, of the alkalinity of the H-functional initiator on the overall alkalinity of the short-chain polyether polyol product. For the sake of uniformity, glycerol was used as the H-functional initiator in each example. Specifically, the alkalinity of the glycerol was measured prior to the reaction and compared to the overall contribution of the glycerol to the alkalinity of the short-chain polyether polyol and the final alkalinity of the short-chain polyether polyol. The results are summarized in fig. 2. As shown in fig. 2, plant-based glycerin generally has a lower alkalinity than tallow-based glycerin. Furthermore, plant-based glycerol generally contributes less to the alkalinity of the short-chain polyether polyol and results in short-chain polyether polyol products that generally have lower alkalinity values.

Example 2 production trends using tallow-based and vegetable-based glycerols as H-functional initiators

Many continuous batches of short-chain polyether polyols are produced using tallow-based glycerol. The tallow-based glycerol was then replaced with the plant-based glycerol (after the dashed line oriented perpendicular to the x-axis of fig. 3), and many additional consecutive batches of short-chain polyether polyol were produced using the plant-based glycerol. The target alkalinity level for each of these batches was less than or equal to 0.60 meq/kg. The results of these test batches are shown in figure 3. As shown in fig. 3, when tallow-based glycerol was used as the H-functional initiator, the final basicity of the short-chain polyether polyol was fairly consistent approaching or exceeding the target threshold of 0.60 meq/kg. In contrast, when plant-based glycerol was used as the H-functional initiator (values shown to the right of the vertical dashed line oriented perpendicular to the x-axis of fig. 3), the final alkalinity remained much more consistently well below the target threshold of 0.60meq/kg, and rarely approached or exceeded the target threshold. In addition, from the percent neutralization values, it can be seen that the amount of neutralizing acid added in each batch exceeded the theoretical neutralization value (the theoretical neutralization value is represented by the horizontal dashed line oriented parallel to the x-axis of fig. 3). This further confirms that the change in alkalinity using plant based glycerol compared to tallow based glycerol is not merely a factor in the amount of neutralizing acid below the theoretical neutralization value for a given batch. Thus, by using plant-based glycerin, the production process is more capable of producing short-chain polyether polyols with low and consistent alkalinity levels without the need to increase the amount of neutralizing acid or adsorbent.

It should be understood that the above-described methods are only illustrative of some embodiments of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention, and the appended claims are intended to cover such modifications and arrangements. Thus, while the invention has been described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred embodiments of the invention, it will be apparent to those of ordinary skill in the art that variations may be made without departing from the principles and concepts set forth herein.

Claims (17)

1. A method of producing a short-chain polyether polyol comprising:

catalyzing polymerization of a reaction mixture comprising an H-functional initiator and alkylene oxide monomers with an alkaline catalyst to form a crude alkaline short-chain polyether polyol, the H-functional initiator comprising 80 to 100 wt% plant-based glycerol, based on the total weight of the H-functional initiator;

neutralizing the crude alkaline short-chain polyether polyol with a mineral acid to produce a crude acid-neutralized short-chain polyether polyol having an alkalinity of less than or equal to 0.60 meq/kg; and

the crude acid neutralized short chain polyether polyol is purified to produce a short chain polyether polyol product having a hydroxyl number of from 100mg KOH/g to 1100mg KOH/g.

2. The process of claim 1 wherein the alkylene oxide comprises from 80 to 100 weight percent propylene oxide, based on the total weight of the alkylene oxide.

3. The method of claim 1, wherein the H-functional initiator comprises 95 to 100 weight percent plant-based glycerin, based on the total weight of the H-functional initiator.

4. The method of claim 1, wherein the plant-based glycerol is obtained from the following feedstocks: rapeseed oil, coconut oil, corn oil, olive oil, palm oil, peanut oil, soybean oil, or combinations thereof.

5. The method of claim 1, wherein the H-functional initiator has a basicity less than or equal to 0.30 meq/kg.

6. The method of claim 1, wherein the basic catalyst comprises a C1-C4 alkali metal alkoxide, an alkali metal hydroxide, or a combination thereof.

7. The process of claim 1, wherein the basic catalyst comprises from 60 to 100 wt% potassium hydroxide, based on the total weight of the basic catalyst.

8. The process according to claim 1, wherein the reaction mixture comprises from 0.01 wt% to 0.6 wt% of the basic catalyst, based on the total weight of the reaction mixture.

9. The method of claim 1, wherein the inorganic acid comprises hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, boric acid, or a combination thereof.

10. The method of claim 1, wherein the mineral acid comprises 60 to 100 wt.% sulfuric acid, based on the total weight of the mineral acid.

11. The process of claim 1, wherein the crude acid neutralized short chain polyether polyol has a basicity of less than or equal to 0.40 meq/kg.

12. The process of claim 1, wherein neutralizing further comprises adding an adsorbent to the crude alkaline short-chain polyether polyol to adsorb alkaline catalyst ions.

13. The method of claim 1, wherein the adsorbent comprises aluminum silicate, magnesium silicate, or a combination thereof.

14. The method of claim 1, wherein purifying comprises filtering the crude acid neutralized short chain polyether polyol.

15. The process of claim 1, wherein the purifying comprises removing water from the crude acid neutralized short chain polyether polyol to achieve a water content in the short chain polyether polyol product of less than or equal to 0.10 weight percent water based on the total weight of the short chain polyether polyol product.

16. The process of claim 1, wherein the short-chain polyether polyol product has a hydroxyl number of from 400mg KOH/g to 600mg KOH/g.

17. The process of claim 1, wherein the short-chain polyether polyol product has a hydroxyl value of from 900mg KOH/g to 1100mg KOH/g.

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