EP4090694A1

EP4090694A1 - Methods of manufacturing short chain polyether polyols

Info

Publication number: EP4090694A1
Application number: EP20707868.4A
Authority: EP
Inventors: Anthony R. LOVEDAY; Daniel R. Wagner; Don S. Wardius
Original assignee: Covestro LLC
Current assignee: Covestro LLC
Priority date: 2020-01-15
Filing date: 2020-01-15
Publication date: 2022-11-23
Also published as: WO2021145869A1; CN114945617A

Abstract

The present disclosure describes methods of manufacturing short-chain polyether polyols, including catalyzing polymerization of a reaction mixture comprising an H-functional initiator and an alkylene oxide monomer with an alkaline catalyst to form a crude alkaline short-chain polyether polyol, 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 level of less than or equal to 0.60 meq/kg, and purifying the acid-neutralized short-chain polyether polyol to prepare a polyether polyol product having a hydroxyl value of from 100 mg KOH/g to 1100 mg KOH/g. The H-functional initiator can include from 60 wt% to 100 wt% plant-based H-functional initiator based on a total weight of the H-functional initiator.

Description

METHODS OF MANUFACTURING SHORT CHAIN POLYETHER

POLYOLS

FIELD

This specification pertains generally to methods for manufacturing short- chain polyether polyols using an H-functional initiator comprising plant-based glycerine. This 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 numerous applications. For example, they can be reacted with isocyanates to produce polyurethanes, one of the most versatile polymeric materials in the modem, industrial world. Polymeric polyols generally include two major categories of polyols: polyether polyols and polyester polyols. Polyether polyols are typically made by the reaction of epoxides with an initiator having an active hydrogen atom (i.e., an H-functional initiator). In contrast, polyester polyols are typically made by the reaction of multifunctional carboxylic acids with multifunctional hydroxyl compounds.

Methods of manufacturing polyether polyols generally implement various measures of controlling the alkalinity of the final polyether polyol product. In particular, polyether polyol purification steps generally aim to reduce alkaline ion content until very low levels of alkalinity are achieved (e.g., less than 5-10 ppm, for example). For example, polyether polyols are typically made via an alkoxylation reaction using an alkaline catalyst, which is subsequently neutralized with an acid and filtered out of the crude polyether polyol. However, a problem that has been observed is that the alkalinity levels of certain short-chain polyether polyols made using a glycerine H-functional initiator and an alkaline catalyst can be inconsistent and often too high. Further, residual alkaline ions in the crude polyether polyol can adversely interfere with the subsequent reactivity of the polyol, such as in the production of polyurethanes. As a result, it would be desirable to provide a process for producing such short-chain polyether polyols that provides consistently low alkalinity levels. BRIEF DESCRIPTION OF THE DRAWINGS

Invention features and advantages will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, various invention embodiments; and, wherein:

FIG. 1 is a flow chart of a method of manufacturing short-chain polyether polyols;

FIG. 2 is a graph of the effect of various H-functional initiators on alkalinity levels for different batches of short-chain poly ether polyols; and

FIG. 3 is a graph of alkalinity trends for tallow-based vs. plant-based H- functional initiators on 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 will nevertheless be understood that no limitation of the scope or to specific invention embodiments is thereby intended.

SUMMARY

In certain respects, the present disclosure is directed to methods of manufacturing short-chain polyether polyols. The methods can comprise catalyzing polymerization of a reaction mixture comprising an H-functional initiator and an alkylene oxide monomer with an alkaline catalyst to form a crude alkaline short-chain polyether polyol, 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 level of less than or equal to 0.60 meq/kg, and purifying the crude acid-neutralized short-chain polyether polyol to prepare a short-chain polyether polyol product having a hydroxyl value of from 100 mg KOH/g to 1100 mg KOH/g. The H-functional initiator can include from 60 wt% to 100 wt% plant-based glycerine based on a total weight of the H- functional initiator. DESCRIPTION OF EMBODIMENTS

Although the following detailed description contains many specifics for the purpose of illustration, a person 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 set forth. 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 written description, the singular forms “a,” “an” and “the” include express support for plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a polyol” or “the polyol” can include a plurality of such polyols.

In this application, “comprises,” “comprising,” “containing” and “having” and the like can have the meaning ascribed to them in U.S. Patent law and can mean “includes,” “including,” and the like, and are generally interpreted to be open ended terms. The terms “consisting of’ or “consists of’ are closed terms, and include only the components, structures, steps, or the like specifically listed in conjunction with such terms, as well as that which is in accordance with U.S. Patent law. “Consisting essentially of’ or “consists essentially of’ have the meaning generally ascribed to them by U.S. Patent law. In particular, such terms are generally closed terms, with the exception of allowing inclusion of additional items, materials, components, steps, or elements, that do not materially affect the basic and novel characteristics or function of the item(s) used in connection therewith. For example, trace elements present in a composition, but not affecting the compositions nature or characteristics would be permissible if present under the “consisting essentially of’ language, even though not expressly recited in a list of items following such terminology. When using an open ended term, like “comprising” or “including,” in this written description it is understood that direct support should be afforded also to “consisting essentially of’ language as well as “consisting of’ language as if stated explicitly 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 is described herein as comprising a series of steps, the order of such steps as presented herein is not necessarily the only order in which such steps may be performed, and certain of the stated steps may possibly be omitted and/or certain other steps not described herein may possibly be added to the method.

As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, a composition that is “substantially free of’ particles would either completely lack particles, or so nearly completely lack particles that the effect would be the same as if it completely lacked particles. In other words, a composition that is “substantially free of’ an ingredient or element may still actually contain such item as long as there is no measurable effect thereof. As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint. Unless otherwise stated, use of the term “about” in accordance with a specific number or numerical range should also be understood to provide support for such numerical terms or range without the term “about”. For example, for the sake of 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.” Furthermore, it is to be understood that in this specification support for actual numerical values is provided even when the term “about” is used therewith. For example, the recitation of “about” 30 should be construed as not only providing support for values a little above and a little below 30, but also for the actual numerical value of 30 as well. For example, in some cases, “about” refers to an amount within 10% of the stated value. In other examples, “about” refers to an amount within 5% of the 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.

As used herein, the term “functionality” refers to the average number of reactive hydroxyl groups, -OH, present per molecule of the -OH functional material that is being described. In the production of polyurethane foams, the hydroxyl groups react with isocyanate groups, -NCO, that are attached to the isocyanate compound. The term “hydroxyl number” refers to the number of reactive hydroxyl groups available for reaction, and is expressed as the number of milligrams of potassium hydroxide equivalent to the hydroxyl content of one gram of the polyol (ASTM D4274-16). The term “equivalent weight” refers to the weight of a compound divided by its valence. For a polyol, the equivalent weight is the weight of the polyol that will combine with an isocyanate group, and may be calculated by dividing the molecular weight of the polyol by its functionality. The equivalent weight of a polyol may also be calculated by dividing 56,100 by the hydroxyl number of the polyol - Equivalent Weight (g/eq) = (56.1 x 1000)/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. As an 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. Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc., as well as 1, 2, 3, 4, and 5, individually.

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

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

Example Embodiments

An initial overview of invention embodiments is provided below and specific embodiments are then described in further detail. This initial summary is intended to aid readers in understanding the technological 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 manufacturing short-chain polyether polyols described herein provide a variety of measures for controlling alkalinity throughout the manufacturing process to help provide consistently low alkalinity levels. For example, the methods of manufacturing short-chain polyether polyols can include catalyzing polymerization of a reaction mixture including an H-functional initiator and an alkylene oxide monomer. When preparing the reaction mixture, care can be taken in selecting an H-functional initiator, particularly glycerine, that minimizes the overall contribution of the H-functional initiator to the final alkalinity of the short-chain polyether polyol product. Otherwise, the manufacturing method can require additional time and cost in purifying the short-chain polyether polyol product to achieve suitable alkalinity levels. For example, it has been discovered that plant-based (e.g., vegetable-based, nut-based, legume-based, for example) glycerine can generally have a lower alkalinity level as compared to tallow-based (i.e., animal fat-based) glycerine. Thus, in some examples, plant-based glycerine contributes less to the final alkalinity of the short-chain polyether polyol product than a tallow-based glycerine.

With this in mind, the present methods can generally include a plant-based glycerine in the reaction mixture to help minimize initial alkalinity levels 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 the sake of simplicity, “glycerine” will be used herein to refer to “glycerine,” “glycerin,” and “glycerol,” each of which can be used interchangeably herein. With this in mind, in some examples, the H-functional initiator can include from about 60 wt% to about 100 wt% plant-based glycerine based on a total weight of the H-functional initiator in the reaction mixture. In some further examples, the H- functional initiator can 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% plant-based glycerine based on a total weight of the H-functional initiator in the reaction mixture.

In some examples, the plant-based glycerine can be combined with a tallow-based H-functional initiator to minimize initial alkalinity levels of the reaction mixture. In other examples, the plant-based glycerine can be combined with an additional plant-based H-functional initiator to minimize initial alkalinity levels of the reaction mixture. In yet further examples, the H-functional initiator can include entirely plant-based glycerine.

Plant-based H-functional initiators can be obtained from a variety of plant- based feedstocks, such as various cooking oils, or mixtures thereof, for example. Non-limiting examples of plant-based feedstocks can include canola oil, cottonseed oil, peanut oil, flaxseed oil, coconut oil, linseed oil, corn oil, olive oil, palm kernel oil, palm oil, castor oil, rapeseed oil, sesame oil, soybean oil, sunflower seed oil, the like, and combinations thereof. In some specific examples, the plant-based glycerine can be obtained from a feedstock including canola oil, coconut oil, corn oil, olive oil, palm oil, peanut oil, soybean oil, or a combination thereof.

A variety of H- functional initiators can be included in the reaction mixture, with the proviso that at least a portion (e.g., at least 60 wt%) of the H-functional initiator comprises a plant-based glycerin. Non-limiting examples of H-functional initiators can include aliphatic or aromatic N-mono-, N,N-, and N,N’-dialkyl substituted diamines with 1 to 4 carbon atoms in the alkyl radical, such as mono- and dialkyl substituted ethylenediamine, diethylenetriamine, triethylene-tetramine,

1.5-pentanediamine, 1,3-propylenediamine, 1,3- and/or 1 ,4-butylenediamine, 1,2-, 1,3-, 1,4-, 1,5- and/or 1,6-hexamethylenediamine, phenylenediamine, 2,4 — and

2.6-toluenediamine, 4,4’-, 2,4-, and/or 2,2’-diaminodiphenylmethane, the like, or a combination thereof. Additional examples of H-functional initiators can include ethanolamine, diethanolamine, N-methyl- and N-ethyl alkanolamines, such as N- methyl- and N-ethyl-diethanolamine and triethanolamine, and ammonia, the like, or a combination thereof. Still additional examples of H-functional initiators can include monofunctional compounds, such as butyl carbitol, and multifunctional 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, glycerine, trimethylol-propane, pentaerythritol, sorbitol, sucrose, the like, or a combination thereof. The listed H-functional initiators can be used individually or as mixtures. Depending on the particular H-functional initiator employed, the resulting short-chain polyether polyol can be a diol, a triol, or other higher order polyol. In some specific examples, the resulting short-chain polyether polyol can include a diol. In another specific example, the resulting short-chain polyether polyol can be or include a triol.

Regardless of the specific individual H-functional initiator, or combination of H-functional initiators, employed in the reaction mixture, the overall alkalinity level of the H-functional initiator can be maintained at a low level. This minimizes the overall contribution of the H-functional initiator to the final alkalinity of the short-chain polyether polyol. With this in mind, the H-functional initiator can generally have an alkalinity level of less than or equal to 0.30 milliequivalents per kilogram (meq/kg). In some additional examples, the H-functional initiator can have an alkalinity level of less than or equal to 0.25 meq/kg, less than or equal to 0.20 meq/kg, less than 0.15 meq/kg, or less than or equal to 0.10 meq/kg. As previously described, using an H-functional initiator having alkalinity levels within these ranges can help minimize the contribution of the H-functional initiator to the initial alkalinity of the reaction mixture and to the overall alkalinity of the short-chain polyether polyol product. The alkalinity level of the H- functional initiator can be measured according to ASTM D4662-15, or other comparable method.

In addition to the H-functional initiator, the reaction mixture can further include an alkylene oxide monomer. Non-limiting examples of alkylene oxide monomers can include styrene oxide, ethylene oxide, propylene oxide, butylene oxide, the like, or a combination thereof. The alkylene oxide monomers may be used individually, sequentially, or as mixtures of two or more thereof. In some specific examples, the alkylene oxide monomer can 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 a total weight of the alkylene oxide monomer. In some additional examples, the alkylene oxide monomer can 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% styrene oxide based on a total weight of the alkylene oxide monomer. In some examples, the alkylene oxide monomer can 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% butylene oxide based on a total weight of the alkylene oxide monomer. In some other examples, the alkylene oxide monomer can 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 a total weight of the alkylene oxide monomer. In still additional examples, the alkylene oxide monomer can include from about 90 wt% to about 100 wt% or from about 95 wt% to about 100 wt% propylene oxide based on a total weight of the alkylene oxide monomer.

The methods of manufacturing short-chain polyether polyols can further include catalyzing polymerization of the alkylene oxide monomer to form a crude short-chain polyether polyol. Polymerization of the alkylene oxide monomer can be catalyzed in a variety of ways. For example, catalyzing alkoxylation of the alkylene oxide monomer can be performed by elevating the temperature of the reaction mixture, charging the reaction mixture with an alkaline catalyst, or a combination thereof. For example, in some cases, catalyzing can be performed at a high-temperature either without the use of a catalyst, or with reduced amount of catalyst, which can allow for a filtration-free or minimized filtration process. As such, in some examples, a high-temperature process can help control or minimize the alkalinity of the reaction mixture. It is noted that achieving desirable reaction rates by employing high-temperature catalysis alone, without the use of an alkaline catalyst, may tend toward temperature levels that can cause deleterious effects in the final short-chain polyether polyol product. Conversely, high amounts of alkaline catalyst can be charged to the reaction mixture at much lower temperatures to provide greater thermal stability and an equivalent or faster reaction rate. The trade-off here can be increased viscosity of the reaction mixture and increased neutralization and filtration requirements for the manufacturing process.

Thus, while not absolutely required, the methods of manufacturing short- chain polyether polyols described herein can generally include charging the reaction mixture with an alkaline catalyst at a temperature of from about 50 °C to about 125 °C. In further detail, a variety of alkaline catalysts can be added to or included in the reaction mixture to catalyze polymerization of the alkylene oxide monomer to form a crude alkaline short-chain polyether polyol. Non-limiting examples can include a C1-C4 alkali alkoxide, an alkali hydroxide, the like, or a combination thereof. C1-C4 alkali alkoxides can include sodium methylate, sodium ethylate, potassium ethylate, potassium isopropylate, sodium butylate, the like, or a combination thereof, for example. Alkali hydroxides can include sodium hydroxide, potassium hydroxide, cesium hydroxide, strontium hydroxide, barium hydroxide, the like, or a combination thereof, for example. The alkali hydroxides can be employed as either solid alkali hydroxide catalysts or as an aqueous alkali 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% aqueous alkali hydroxide catalyst). Thus, in some examples, the alkaline catalyst can include from about 40 wt% to about 100 wt% alkali hydroxide (as either solid alkali hydroxide or aqueous alkali hydroxide) based on a total weight of the alkaline catalyst and from about 0 wt% to about 60 wt% of another alkaline catalyst. In some additional examples, the alkaline catalyst can include 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% alkali hydroxide (as either solid alkali hydroxide or aqueous alkali hydroxide) based on a total weight of the alkaline catalyst and any remaining amount of another alkaline catalyst. In some specific examples, the alkaline catalyst can include from about 40 wt% to about 100 wt% potassium hydroxide (either as solid potassium hydroxide or aqueous potassium hydroxide) based on a total weight of the alkaline catalyst and from about 0 wt% to about 60 wt% of another alkaline catalyst. In some additional examples, the alkaline catalyst can include 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% potassium hydroxide (either as solid potassium hydroxide or aqueous potassium hydroxide) based on a total weight of the alkaline catalyst and any remaining amount of another alkaline catalyst.

As described above, because the alkaline catalyst is generally employed in combination with relatively high temperatures, the amount of alkaline catalyst can be maintained at a concentration that reduces or minimizes neutralization and filtration requirements. In some specific examples, the reaction mixture can include from about 0.01 wt% to about 1 wt% alkaline catalyst based on a total weight of the reaction mixture. In some additional examples, the reaction mixture can 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% alkaline catalyst based on a total weight of the reaction mixture. In some specific examples, the reaction mixture can include from about 0.05 wt% to about 0.5 wt% alkaline catalyst based on a total weight of the reaction mixture.

The crude alkaline short-chain polyether polyol achieved from the catalyzed polymerization of the alkylene oxide monomer can be neutralized with an inorganic acid to prepare a crude acid-neutralized short-chain polyether polyol. The amount of inorganic acid added to the crude alkaline short-chain polyether polyol can vary depending on the amount alkaline catalyst employed to catalyze the alkoxylation reaction. Nonetheless, neutralizing the crude alkaline short-chain polyether polyol can include adding an amount of inorganic acid to achieve a crude acid-neutralized short-chain polyether polyol having an alkalinity level of less than or equal to 0.60 meq/kg. In some additional examples, neutralizing the crude alkaline short-chain polyether polyol can include adding an amount of inorganic acid to achieve a crude acid-neutralized short-chain polyether polyol having an alkalinity level of less than or equal to 0.40 meq/kg, less than or equal to 0.30 meq/kg, less than or equal to 0.20 meq/kg, or less than or equal to 0.10 meq/kg. Alkalinity values can be determined in accordance with ASTM D6437 or other comparable test method. It is noted that while neutralization is performed prior to purification, the final alkalinity measurement for the short-chain polyether polyol using ASTM D6437 is generally performed after purification.

A variety of inorganic acids can be used to neutralize the crude alkaline short-chain polyether polyol. Non-limiting examples of inorganic acids can include hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, boric acid, the like, or a combination thereof. The inorganic acids can be concentrated or dilute, as desired. In some examples, the inorganic acids can have a concentration of from about 5 wt% to about 98 wt% in a suitable diluent (e.g., water). In some examples, the inorganic acid can include hydrochloric acid. In some other examples, the inorganic acid can include phosphoric acid. In additional examples, the inorganic acid can include nitric acid. In still additional examples, the inorganic acid can include boric acid. In yet additional examples, the inorganic acid can include sulfuric acid. In some specific examples, the inorganic acid can include from about 60 wt % to about 100 wt % sulfuric acid (as either dilute sulfuric acid or concentrated sulfuric acid) based on a total weight of the inorganic acid and from 0 wt% to 40 wt% of another neutralizing acid. In some additional examples, the inorganic acid can 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 either dilute sulfuric acid or concentrated sulfuric acid) based on a 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 alkaline catalyst can vary depending on the particular catalyst and amount thereof employed in the reaction mixture. Generally, the amount of inorganic acid can be an amount from about 90% to about 115% or from about 100% to about 110% of the theoretical amount of the respective acid needed to completely neutralize the alkaline catalyst. Additionally, neutralization can be performed at a variety of temperatures. In some specific examples, neutralization can be performed at a temperature of from about 50 °C to about 130 °C.

In some examples, neutralizing can further include adding an adsorbent to the crude alkaline short-chain polyether polyol to adsorb alkaline catalyst ions (e.g., potassium ions where potassium hydroxide is used as the alkaline catalyst, for example). The adsorbents can typically have a high surface area (e.g., 100-250 m²/g, for example) to help facilitate adsorption efficiency of catalyst ions. Non limiting examples of adsorbents can include aluminum silicates, such as montmorillonites, bentonites, activated Fuller’s earth, the like, or a combination thereof. Adsorbents can also include magnesium silicates, such as MAGNESOL®, or the like. Any of these adsorbents, or the like, can be used individually 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 prepare a short-chain polyether polyol product. Purification can include filtration, removal of water, or a variety of addition steps to achieve the short-chain polyether polyol product. For example, in some cases, purification can include filtering the crude acid-neutralized polyether polyol. Filtration can help remove neutralized alkaline catalyst salt crystals, any added adsorbents, etc.

In some additional examples, purification can include removing water from the crude acid-neutralized short-chain polyether polyol. In some examples, water can be removed by vacuum distillation or other suitable process. Generally, water removal can be performed to achieve a water level of less than or equal to 0.1 wt% water based on a total weight of the short-chain polyether polyol product. In still additional examples, the water level can be reduced to an amount of less than or equal to 0.08 wt% water or 0.05 wt% water based on a total weight of the short-chain polyether polyol product.

As described above, the present methods are directed to manufacturing short-chain polyether polyols. As used herein, “short-chain” polyether polyols refer to polyols having a hydroxyl value of from about 100 mg KOH/g to about 1100 mg KOH/g determined according to ASTM D6342-12. Thus, purification of the crude acid-neutralized short-chain polyether polyol provides a short-chain poly ether polyol product having a hydroxyl value of from about 100 mg KOH/g to about 1100 mg KOH/g. In some additional examples, the short-chain polyether polyol product can have a hydroxyl value of from about 100 mg KOH/g to about 400 mg KOH/g, about 200 mg KOH/g to about 600 mg KOH/g, from about 400 mg KOH/g to about 800 mg KOH/g, or from about 600 mg KOH/g to about 1100 mg KOH/g. In some specific examples, the short-chain polyether polyol can have a hydroxyl value of from about 100 mg KOH/g to about 200 mg KOH/g, about 400 mg KOH/g to about 600 mg KOH/g, or from about 900 mg KOH/g to about 1100 mg KOH/g.

FIG. 1 depicts one example of a method 100 of manufacturing a short- chain polyether polyol. The method 100 can include catalyzing 110 polymerization of a reaction mixture including an H-functional initiator and an alkylene oxide monomer with an alkaline catalyst to form a crude alkaline short- chain poly ether polyol, the H-functional initiator comprising from 60 wt% to 100 wt% plant-based glycerine based on a total weight of the H-functional initiator. Additionally, the method 100 can include neutralizing 120 the crude alkaline short-chain polyether polyol with an inorganic acid to prepare 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 can further include purifying 130 the crude acid-neutralized short-chain polyether polyol to prepare a short-chain polyether polyol product having a hydroxyl value of from 100 mg KOH/g to 1100 mg KOH/g.

It is additionally noted, that the short-chain polyether polyol product described herein can be further reacted with a diisocyanate, a polyisocyanate, or a combination thereof to produce a rigid foam or other suitable polyurethane-based product. In such examples, any known organic isocyanates, modified isocyanates, or isocyanate-terminated perpolymers made from any of the known organic isocyanates 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-toluene diisocyanate, 2,6-toluene diisocyanate, 1,6- hexamethylene diisocyanate, 1,4-hexamethylene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclo-hexane diisocyanate, isomers of hexahydro-toluene diisocyanate, isophorone diisocyanate, dicyclo-hexylmethane diisocyanates, 1,5- naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'- diphenylmethane diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy- 4,4'-biphenylene diisocyanate and 3,3'-dimethyldiphenyl-propane-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 the polymethylene polyphenyl-polyisocyanates.

Undistilled or crude polyisocyanates may also be used. The crude toluene diisocyanate obtained by phosgenating a mixture of toluene diamines and the crude diphenylmethane diisocyanate obtained by phosgenating crude diphenylmethanediamine (polymeric MDI) are examples of suitable crude polyisocyanates. Suitable undistilled or crude polyisocyanates are disclosed in U.S. Pat. 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 from 25 to 35 weight percent, such as from 29 to 34 weight percent, such as those based on polyether polyols or polyester polyols and diphenylmethane diisocyanate.

In some additional examples, a blowing agent can be used in the production of the polyurethane product (e.g., a rigid foam, for example). Non limiting examples of blowing agents can include a physical blowing agent comprising an HCFO, a carbon dioxide generating chemical blowing agent, the like, or a combination thereof.

Suitable HCFOs include l-chloro-3,3,3-trifluoropropene (HCFO-1233zd, E and/or Z isomers), 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), HCF01223, l,2-dichloro-l,2-difluoroethene (E and/or Z isomers), 3,3-dichloro-3- fluoropropene, 2-chloro l,l,l,4,4,4-hexafluorobutene-2 (E and/or Z isomers), 2- chloro-l,l,l,3,4,4,4-heptafluorobutene-2 (E and/or Z isomers). In some implementations, the boiling point, at atmospheric pressure, of the HCFO is at least -25°C, at least -20°C, or, in some cases, at least -19°C, and 40°C or less, such as 35°C or less, or, in some cases 33°C or less. The HCFO may have a boiling point, at atmospheric pressure, of, for example, -25°C to 40°C, or -20°C to 35°C, or -19°C to 33°C.

In certain implementations, one or more other physical blowing agents can be used, such as other halogenated blowing agents, such as CFCs, HCFCs, and/or HFCs and/or hydrocarbon blowing agents, such as butane, n-pentane, cyclopentane, hexane, and/or isopentane (i.e. 2-methylbutane), etc. In some examples, a carbon dioxide generating chemical blowing agent can be used, such as water and/or formate-blocked amines.

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

If desired, the blowing agent composition may include 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) hydrofluorocarbons (c) hydrocarbons, such as any of the pentane isomers and butane isomers; (d) hydrofluoroethers (HFEs); (e) Cl to C5 alcohols, Cl to C4 aldehydes, Cl to C4 ketones, Cl to C4 ethers and diethers and carbon dioxide. Specific examples of such blowing agents are described in United States Patent Application Publication No. US 2014/0371338 A1 at [0051] and [0053], the cited portion of which being incorporated herein by reference.

Various other components can also be combined with the polyol to generate a suitable polyurethane-based product. Non-limiting examples can include a surfactant, a blowing catalyst, a trimerization catalyst, a gelling catalyst, a colorant, an antioxidant, a flame retardant, a stabilizer, a filler, the like, or a combination thereof. Thus, a variety of polyurethane-based products can be produced using the short-chain polyether polyols described herein. In connection with the general description provided herein, a few non limiting example embodiments of methods of manufacturing short-chain polyether polyols are provided below, as follows:

Clause 1. A method of manufacturing a short-chain poly ether polyol, comprising: catalyzing polymerization of a reaction mixture comprising an H- functional initiator and an alkylene oxide monomer, the H-functional initiator comprising from 60 wt% to 100 wt% plant-based glycerine based on a total weight of the H-functional initiator, with an alkaline catalyst to form a crude alkaline short-chain poly ether polyol; and 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 level of less than or equal to 0.60 meq/kg; and purifying the crude acid-neutralized short-chain poly ether polyol to prepare a short-chain polyether polyol product having a hydroxyl value of from 100 mg KOH/g to 1100 mg KOH/g.

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

Clause 3. The method of clause 1 or clause 2, wherein the H-functional initiator comprises from 95 wt% to 100 wt% plant-based glycerine based on a total weight of the H-functional initiator.

Clause 4. The method of any one of clauses 1-3, wherein the plant-based glycerine is obtained from a feedstock comprising canola oil, coconut oil, com oil, olive oil, palm oil, peanut oil, soybean oil, or a combination thereof.

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

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

Clause 7. The method of any one of clauses 1-6, wherein the alkaline catalyst comprises from 60 wt% to 100 wt% potassium hydroxide based on a total weight of the alkaline catalyst.

Clause 8. The method of any one of clauses 1-7, wherein the reaction mixture comprises from 0.01 wt% to 0.6 wt% alkaline catalyst based on a 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 inorganic acid comprises from 60 wt% to 100 wt% sulfuric acid based on a total weight of the inorganic acid.

Clause 11. The method of any one of clauses 1-10, wherein the crude acid- neutralized short-chain polyether polyol has an alkalinity level 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 an aluminum silicate, a 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 a water level of less than or equal to 0.10 wt% water in the short-chain polyether polyol product based on a 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 value of from 400 mg KOH/g to 600 mg KOH/g.

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

Example 1 - Effects of El-Functional Initiator Alkalinity

A number of test batches of short-chain polyether polyols were prepared based on a variety of H-functional initiators from different sources (both plant- 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, glycerine was used in each of the examples as the H-functional initiator. Specifically, the alkalinity of the glycerine was measured prior to reaction and compared to the overall contribution of the glycerine 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 can be seen in FIG. 2, plant-based glycerine generally had lower alkalinity than tallow-based glycerin. Further, plant-based glycerine generally contributed less to the alkalinity of the short-chain polyether polyol and resulted in short-chain poly ether polyol products having generally lower alkalinity values.

Example 2 - Manufacturing Trends using Tallow-Based vs. Plant-Based Glycerine as H-Functional Initiator

A number of consecutive batches of short-chain polyether polyols were manufactured using tallow-based glycerine. The tallow-based glycerine was then replaced with plant-based glycerine (after the dashed line oriented perpendicular to the x-axis of FIG. 3) and a number of additional consecutive batches of short- chain polyether polyols were manufactured using plant-based glycerine. The target alkalinity level for each of these batches was less than or equal to 0.60 meq/kg. The results of these trial batches are illustrated in FIG. 3. As can be seen in FIG. 3, when using tallow-based glycerine as the H-functional initiator, the final alkalinity of the short-chain polyether polyol fairly consistently approximated or exceeded the 0.60 meq/kg target threshold. In contrast, when using plant-based glycerine 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 more consistently remained well below the 0.60 meq/kg target threshold and only rarely approximated or exceeded the target threshold. Additionally, as can be seen from the % neutralization values, an amount of neutralization acid was added to each batch in excess of the theoretical neutralization value (theoretical neutralization value is represented by horizontal dashed line oriented parallel to the x-axis of FIG. 3). This further substantiates that the changes in alkalinity when using the plant-based glycerine versus the tallow-based glycerine were not a mere factor of the amount of neutralization acid being below the theoretical neutralization values for given batches. Thus, by employing plant- based glycerine, the manufacturing method much more consistently produced a short-chain polyether polyol having low alkalinity levels without having to increase amounts of neutralization acid or adsorbents.

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 present 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 including, may be made without departing from the principles and concepts set forth herein.

Claims

CLAIMS What is claimed is:

1. A method of manufacturing a short-chain polyether polyol, comprising: catalyzing polymerization of a reaction mixture comprising an H- functional initiator and an alkylene oxide monomer, the H-functional initiator comprising from 80 wt % to 100 wt % plant-based glycerine based on a total weight of the H-functional initiator, with an alkaline catalyst to form a crude alkaline short-chain poly ether polyol; and 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 level of less than or equal to 0.60 meq/kg; and purifying the crude acid-neutralized short-chain polyether polyol to prepare a short-chain polyether polyol product having a hydroxyl value of from 100 mg KOH/g to 1100 mg KOH/g.

2. The method of claim 1, wherein the alkylene oxide comprises from 80 wt% to 100 wt% propylene oxide based on a total weight of the alkylene oxide.

3. The method of claim 1, wherein the H-functional initiator comprises from 95 wt% to 100 wt% plant-based glycerine based on a total weight of the H-functional initiator.

4. The method of claim 1, wherein the plant-based glycerine is obtained from a feedstock canola oil, coconut oil, com oil, olive oil, palm oil, peanut oil, soybean oil, or a combination thereof.

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

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

7. The method of claim 1, wherein the alkaline catalyst comprises from 80 wt% to 100 wt% potassium hydroxide based on a total weight of the alkaline catalyst.

8. The method of claim 1, wherein the reaction mixture comprises from 0.01 wt% to 0.6 wt% alkaline catalyst based on a 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 inorganic acid comprises from 60 wt% to 100 wt% sulfuric acid based on a total weight of the inorganic acid.

11. The method of claim 1, wherein the crude acid-neutralized short-chain polyether polyol has an alkalinity level of less than or equal to 0.40 meq/kg.

12. The method 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 12, wherein the adsorbent comprises an aluminum silicate, a 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 method of claim 1, wherein purifying comprises removing water from the crude acid-neutralized short-chain polyether polyol to achieve a water level of less than or equal to 0.10 wt% water in the short-chain polyether polyol product based on a total weight of the short-chain polyether polyol product.

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

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