Purified biomass-based compositions containing ethylene glycol and their use to produce polyesters

Abstract

The present invention designs a method of purifying a biomass-based composition comprising ethylene glycol, the method comprising: (a) providing a biomass-based composition comprising water wherein the water content is at least 0.1 wt.% based on the weight of the biomass-based composition; and (b) contacting the biomass-based composition with a solid acid catalyst and contacting the biomass-based composition with an aldehyde removal resin, thereby obtaining a purified biomass-based composition.

Description

Technical Field

[0001] The present invention relates to biomass-based compositions comprising ethylene glycol and related methods and uses thereof. The present invention further relates to methods for producing polyesters using the biomass-based compositions. Background Art

[0002] Ethylene glycol is an organic polyol with the IUPAC name ethane-1,2-diol. Currently, the most common way to obtain ethylene glycol is from fossil fuels. A typical fossil-based ethylene glycol production method uses ethylene produced from petroleum. Ethylene is oxidized in the presence of a catalyst to form ethylene oxide, which is then hydrolyzed to form ethylene glycol.

[0003] Given the changing environmental and economic climate, there is a desire to use ethylene glycol obtained from renewable resources such as biomass, for example sugars. For example, WO2016001169A1 discloses a method for producing ethylene glycol from sugars, which includes pyrolyzing the sugars to form a mixture of C1-C3 oxygenates (such as formaldehyde, glycolaldehyde, glyoxal, acetol, and acetonylaldehyde), and then hydrogenating in the presence of a catalyst to form crude ethylene glycol.

[0004] One of the main industrial uses of ethylene glycol is as a raw material for producing polyesters. Polyesters have a wide range of applications, such as for producing packaging products (such as bottles), textiles, and electronics. A polyester of particular industrial importance is polyethylene terephthalate (PET). Many patent applications disclose methods for purifying crude biomass-based ethylene glycol to produce high-purity ethylene glycol (>99 wt% EG) and claim its suitability for producing PET. For example, WO 2015 / 150520 and WO 2022 / 223867 disclose a purification method involving distillation to obtain high-purity ethylene glycol. CN 106866371A discloses a multi-stage crystallization method as a purification method for producing ethylene glycol with a purity of 98.5%-99.9% from crude ethylene glycol (such as obtained by hydrogenation of HTHP oxalate). None of these patent applications address problems related to impurities, nor measure the UV transmittance or APHA color of the purified ethylene glycol compositions. Nor is PET actually synthesized, and thus there is no measurement of PET properties such as CIELAB color.

[0005] Packaging products typically need to meet strict technical specifications regarding color characteristics. At the same time, the industry also expects the ethylene glycol composition used in the production of packaging products to have specific technical properties in order to produce packaging products that meet the required technical specifications. For example, it is a generally accepted view in the industry that the ethylene glycol composition needs to have a high UV transmittance in order to produce polyester packaging products that meet the necessary technical specifications. For example, this can be seen in Zhang et al., “Identification of impurities affecting commercial ethylene glycol UV transmittance”, J Chromatogr A 904 (2000) 87-97. The article states that the UV transmittance of ethylene glycol is low and thus it is not suitable as a raw material for producing polyester. The article then points out the existence of some major UV-absorbing impurities and suggests removing these impurities (but does not state how) to obtain “polymer-grade” ethylene glycol. As mentioned in the introduction, “Ethylene glycol used for manufacturing polyester should have extremely high purity and must meet special UV transmittance specifications, requiring the UV transmittance of ethylene glycol at 220, 275, and 350 nm to be at least 75%, 95%, and 100% respectively. It is believed that the UV transmittance at these wavelengths indicates the presence of undesirable impurities that will reduce the quality of the resulting polyester.”

[0006] This assumption regarding UV transmittance can also be inferred from the fact that producers of polyester-grade monoethylene glycol specify a minimum UV transmittance at 350, 275, and 220 nm in their product specifications. For example, LyondellBasell (US Sales Specification for Polyester Grade Monoethylene Glycol, Material No. 5017), MEGlobal (Sales Specification for Polyester Grade Monoethylene Glycol, Specified Material 000101232907, 1st Edition January 2019, and Commercial Polyester Grade Sales Specification, Specified Material 000101205133, 1st Edition January 2019) and SABIC (Bulk Technical Data for Monoethylene Glycol, Revision 20220825) all specify a minimum UV transmittance: 98% at 350 nm, 90 - 94% at 275 nm, and 70% at 220 nm.

[0007] In addition, some patent applications related to bio-based polyester-grade ethylene glycol target UV transmittance at 350, 275, and 220 nm. For example, see WO 2015 / 028156, WO 2018 / 089600, WO 2018 / 089605, CN101525424A, and CN 104418997A. For example, CN101525424A mentions that the transmittance of bio-based ethylene glycol suitable for preparing PET in the wavelength range of 190 - 350 nm must be greater than 50%. In addition, CN 1580020A discloses a method for purifying crude ethylene glycol, which particularly emphasizes the ultraviolet absorbance at 220 nm as a key indicator for polyester-grade ethylene glycol. Polyester-grade ethylene glycol is prepared by passing crude ethylene glycol successively through a cation resin (to remove metal iron ions) and an aldehyde adsorption resin. However, this patent neither provides an example of preparing polyester using the said polyester-grade ethylene glycol, nor measures the UV transmittance or APHA color of the purified ethylene glycol composition, let alone actually produces PET or measures the CIELAB color of the PET. This patent suggests using a sequential device to purify ethylene glycol to avoid interference of metal ions with the aldehyde adsorption resin.

[0008] There is a desire to provide a biomass-based composition containing ethylene glycol that can be used to produce polyesters and packaging products and meet the necessary or desired technical specifications of polyesters and packaging products. Similarly, there is a desire to provide an economical and industrially viable method for producing such biomass-based compositions and polyesters. Summary of the Invention

[0009] According to one aspect of the present invention, there is provided a method for purifying a biomass-based composition containing ethylene glycol, the method comprising: (a) providing a biomass-based composition containing water, wherein the water content is at least 0.1 wt.% based on the weight of the biomass-based composition; and (b) contacting the biomass-based composition with a solid acid catalyst and contacting the biomass-based composition with an aldehyde removal resin to provide a purified biomass-based composition.

[0010] In one aspect, the solid acid catalyst contains a sulfonic acid functional group.

[0011] In one aspect, the solid acid catalyst contains one or more of a resin and a zeolite.

[0012] In one aspect, the aldehyde removal resin contains one or more of the following: a primary amine functional group, a secondary amine functional group, a tertiary amine functional group, and a quaternary ammonium functional group. In one aspect, the quaternary ammonium functional group is a quaternary ammonium bisulfite salt functional group.

[0013] In one aspect, the total aldehyde concentration of the purified biomass-based composition is no more than 50 ppm, such as no more than 20 ppm, such as no more than 18 ppm, such as no more than 15 ppm, such as no more than 10 ppm, based on the weight of the purified biomass-based composition.

[0014] In one aspect, the total aldehyde concentration of the biomass-based composition in step (a) is no less than 100 ppm, such as no less than 200 ppm, such as no less than 300 ppm, such as no less than 500 ppm, such as no less than 1000 ppm, based on the weight of the biomass-based composition.

[0015] In one aspect, the solid acid catalyst and the aldehyde removal resin are disposed in a common bed.

[0016] In one aspect, the solid acid catalyst is disposed in a first bed, and the aldehyde removal resin is disposed in a second bed, where the second bed is downstream of the first bed.

[0017] In one aspect, one or both of the contacting process of the biomass-based composition with the solid acid catalyst and the contacting process of the biomass-based composition with the aldehyde removal resin are carried out at a temperature of 10°C to 70°C, such as 35°C to 65°C, such as 40°C to 60°C, such as 45°C to 55°C.

[0018] In one aspect, the method includes: after contacting the biomass-based composition with the solid acid catalyst and with the aldehyde removal resin, contacting the purified biomass-based composition with the aldehyde removal resin.

[0019] In one aspect, the purified biomass-based composition is characterized in that the APHA color value measured according to ASTM D1209-05 is no greater than 5 mg / L PtCo.

[0020] In one aspect, the purified biomass-based composition is characterized in that the APHA color value after heating measured according to ASTM D1209-05 is no greater than 20 mg / L PtCo.

[0021] In one aspect, the method includes: after contacting the biomass-based composition with the solid acid catalyst and with the aldehyde removal resin, subjecting the biomass-based composition to at least one distillation step, and / or subjecting the biomass-based composition to at least one melt crystallization step.

[0022] In one aspect, after the purified biomass-based composition undergoes a dehydration step (e.g., by distillation), the content of ethylene glycol is not less than 98 wt.%, such as not less than 99 wt.%, such as not less than 99.25 wt.%, such as not less than 99.5 wt.%, such as not less than 99.75 wt.%, such as not less than 99.9 wt.%, based on the weight of the purified biomass-based composition. The natural upper limit of ethylene glycol in the purified biomass-based composition is 100 wt.%.

[0023] In one aspect, the method includes: performing at least one distillation step on the biomass-based composition before contacting the biomass-based composition with a solid acid catalyst and with an aldehyde removal resin.

[0024] In one aspect, the biomass-based composition is obtained by pyrolytic cracking of sugar and subsequent hydrogenation.

[0025] According to another aspect of the present invention, there is provided a purified biomass-based composition obtained by the method for purifying a biomass-based composition according to the above aspects of the present invention, wherein the purified biomass-based composition is characterized in that: the APHA colority after heating measured according to ASTM D1209-05 is less than 20 mg / L PtCo; and the UV transmittance at 275 nm measured according to ASTM method E2193-16 is less than 40%.

[0026] According to another aspect of the present invention, there is provided the use of a purified biomass-based composition obtained by the method for purifying a biomass-based composition according to the above aspects of the present invention in the production of a polyester, wherein the polyester is characterized in that it has one or more of the following CIELAB color space values measured according to ASTM D6290-19: L* is not less than 65; a* is from -4 to 4; and b* is from -4 to 4.

[0027] According to another aspect of the present invention, there is provided a method for producing a polyester, the method including contacting a purified biomass-based composition obtained by the method for purifying a biomass-based composition according to the above aspects of the present invention with at least one reagent to form a polyester, wherein the polyester is characterized in that it has one or more of the following CIELAB color space values measured according to ASTM D6290-19: L* is not less than 65; a* is from -4 to 4; and b* is from -4 to 4.

[0028] According to another aspect of the present invention, there is provided a polyester obtained by the method for producing a polyester according to the above aspects of the present invention, wherein the polyester is characterized in that it has one or more of the following CIELAB color space values measured according to ASTM D6290-19: L* is not less than 65; a* is from -4 to 4; and b* is from -4 to 4.

[0029] In one aspect, the polyester is characterized by having one or more of the following CIELAB color space values determined according to ASTM D6290-19: L* is not less than 85; a* is from -2 to 2; and b* is from -2 to 2. In one aspect, the polyester is characterized in that the CIELAB color space value b* determined according to ASTM D6290-19 is from -4 to 4, preferably from -2 to 2. In one aspect, the polyester is characterized in that the CIELAB color space value a* determined according to ASTM D6290-19 is from -4 to 4, preferably from -2 to 2. In one aspect, the polyester is characterized in that the CIELAB color space value L* determined according to ASTM D6290-19 is not less than 65, preferably not less than 85.

[0030] According to another aspect of the present invention, there is provided a packaging article or preform made of the polyester according to the above aspect of the present invention.

[0031] According to another aspect of the present invention, there is provided a method for purifying a glycol-containing biomass-based composition, the method comprising: (a) providing a biomass-based composition containing water, wherein the water content is at least 0.1 wt.% based on the weight of the biomass-based composition; and (b) contacting the biomass-based composition with an aldehyde removal resin to provide a purified biomass-based composition.

[0032] In any of the above aspects of the present invention, the polyester may comprise polyethylene terephthalate.

[0033] The features of any aspect of the present invention may be combined with one or more features of any other aspect of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] As described herein, in one aspect of the present invention, there is provided a method for purifying a glycol-containing biomass-based composition, the method comprising: (a) providing a biomass-based composition containing water, wherein the water content is at least 0.1 wt.% based on the weight of the biomass-based composition; and (b) contacting the biomass-based composition with a solid acid catalyst and contacting the biomass-based composition with an aldehyde removal resin to provide a purified biomass-based composition.

[0036] Ethylene glycol (monoethylene glycol) has various applications, including as an antifreeze and as a monomer for manufacturing polyesters. We have found that biomass-based compositions containing ethylene glycol may contain small amounts of free aldehydes and acetals, and the presence of these components (e.g., at ppm-level concentrations) can cause coloration in polyesters made from the biomass-based compositions. This problem is particularly prominent when a specific color characteristic (e.g., reduced chromaticity, such as substantially colorless) is required or demanded for the end product (e.g., a bottle). We have found that treating the biomass-based composition containing ethylene glycol with an aldehyde removal resin alone may not be effective. For example, we have found that a biomass-based composition containing ethylene glycol treated only with an aldehyde removal resin may form a polyester with poor color characteristics (e.g., yellowing). We have unexpectedly found that contacting the biomass-based composition containing ethylene glycol with a solid acid catalyst and an aldehyde removal resin can provide a biomass-based composition that can be used to form a polyester with desirable color characteristics (e.g., reduced chromaticity, such as substantially colorless).

[0037] Purification

[0038] Herein, "purified" or "purifying" or "after purification" can be regarded as enriching ethylene glycol in the composition by removing other components from the composition. "Other components" can include impurities, i.e., components present in small concentrations, such as aldehydes or unidentified impurities.

[0039] Biomass-based composition

[0040] In one aspect, the biomass-based composition has a carbon-14 ( 14 C) content higher than 0.5 parts per trillion of the total carbon content, and this content is determined by ASTM D6866-22.

[0041] In one aspect, the biomass-based composition is obtained by pyrolytic cracking of sugars.

[0042] In one aspect, the biomass-based composition is obtained by hydrogenolysis of sugars.

[0043] A method for purifying a biomass-based composition, the method comprising (a) providing a biomass-based composition containing water, wherein the water content is at least 0.1 wt.% based on the weight of the biomass-based composition.

[0044] In one aspect, the biomass-based composition contains water, and the water content is at least 2 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is at least 5 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is at least 8 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is at least 10 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is at least 15 wt.% based on the weight of the biomass-based composition.

[0045] In one aspect, the biomass-based composition contains water, and the water content is not more than 80 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is not more than 70 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is not more than 60 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is not more than 50 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is not more than 40 wt.% based on the weight of the biomass-based composition.

[0046] In one aspect, the biomass-based composition contains water, and the water content is 2 wt.% to 80 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is 5 wt.% to 70 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is 8 wt.% to 60 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is 10 wt.% to 50 wt.% based on the weight of the biomass-based composition. In one aspect, the biomass-based composition contains water, and the water content is 15 wt.% to 40 wt.% based on the weight of the biomass-based composition.

[0047] In one aspect, the biomass-based composition is obtained by pyrolytic cracking of biomass and subsequent hydrogenation. Alternatively, the biomass-based composition can be obtained by hydrocracking of biomass. Hydrocracking is a chemical reaction similar to hydrolysis, in which the role of hydrogen is similar to that of water. In hydrocracking, usually a bond in an organic molecule is broken, and a hydrogen atom is added to each resulting molecular fragment. In one aspect, the biomass contains one or more of lignocellulose, lignin, sewage sludge, lipids, proteins, and carbohydrates.

[0048] The pyrolysis (or thermolysis) of biomass describes processes in which biomass feedstocks are subjected to heat treatment, resulting in the decomposition of their components and the production of pyrolysis products. The pyrolysis of glucose and the hydrogenation of the resulting pyrolysis products are known according to, for example, Schandel et al., ChemSusChem, 2020, 13, 688 - 692, US 9,926,247, and WO 2017 / 216311.

[0049] Biomass includes all types of biogenic materials, i.e., materials formed by the fixation of CO2 from the atmosphere in the recent past (i.e., within the last century). This includes lignocellulose, lignin, sewage sludge, lipids, proteins, and carbohydrates.

[0050] Carbohydrates include polysaccharides, oligosaccharides, and sugars. Polysaccharides include long-chain polymers of sugars, including cellulose, hemicellulose, and starch. Oligosaccharides include short-chain polymers of sugars (4 - 10 monosaccharide units). Sugars include trisaccharides, disaccharides, and monosaccharides. Trisaccharides include maltotriose. Disaccharides include sucrose, maltose, lactose, and cellobiose. Monosaccharides include all monosaccharides belonging to the classes of trioses, tetroses, pentoses, and hexoses, preferably pentoses and hexoses, more preferably glucose, fructose, mannose, galactose, xylose, and arabinose or mixtures thereof. As a monosaccharide feedstock, glucose is most preferred. In a monosaccharide feedstock, the weight percentage of disaccharides and trisaccharides relative to monosaccharides can be up to 5% and still be considered a monosaccharide feedstock.

[0051] In one aspect, the biomass-based composition is obtained by subjecting carbohydrates to pyrolysis and subsequent hydrogenation. In one aspect, the biomass-based composition is obtained by subjecting polysaccharides, oligosaccharides, sugars, and mixtures thereof to pyrolysis and subsequent hydrogenation. In one aspect, the biomass-based composition is obtained by subjecting sugars to pyrolysis and subsequent hydrogenation. In one aspect, the biomass-based composition is obtained by subjecting polysaccharides, oligosaccharides, trisaccharides, disaccharides, monosaccharides, and mixtures thereof to pyrolysis and subsequent hydrogenation. In one aspect, the biomass-based composition is obtained by subjecting disaccharides, monosaccharides, and mixtures thereof to pyrolysis and subsequent hydrogenation. In one aspect, the biomass-based composition is obtained by subjecting at least disaccharides to pyrolysis and subsequent hydrogenation. In one aspect, the biomass-based composition is obtained by subjecting at least monosaccharides to pyrolysis and subsequent hydrogenation.

[0052] Pyrolysis refers to the process of applying heat (usually 300 - 700 °C) to biomass raw materials and converting them into pyrolysis products (or pyrolysis cracking products) within a certain period of time. Pyrolysis does not include the conditions or processes that cause a large amount of combustion or gasification of the raw materials into permanent gases. Heat can be applied by burning a small amount of the raw materials by introducing oxygen or an oxidant, or by applying heat externally, such as contacting with a hot surface, gas, liquid, or solid to transfer heat to the raw materials. Pyrolysis can be carried out in various reactors, such as bubbling fluidized bed reactors, circulating fluidized bed reactors, ablative reactors, rotating cone reactors, micro-pyrolysis units, etc. Heat can be applied over a long time (slow pyrolysis, > 5 minutes), medium time (conventional pyrolysis, 30 - 300 seconds), and short time (fast pyrolysis, such as less than 30 seconds, usually about 0.5 - 2 seconds). The duration and temperature of pyrolysis affect the composition of the pyrolysis products.

[0053] Monosaccharide pyrolysis refers to the process of converting monosaccharide raw materials (i.e., monosaccharide raw materials without a large amount of lignocellulose, lignin, lipids, cellulose, hemicellulose, starch, protein, oligosaccharides, trisaccharides, and disaccharides) into pyrolysis products through pyrolysis. Monosaccharide pyrolysis is called "dry monosaccharide pyrolysis" if the water content of the monosaccharide raw materials used is less than 15 wt.% (based on the weight of the monosaccharide raw materials). Monosaccharide pyrolysis carried out on monosaccharide raw materials with a water content exceeding 15 wt.% (based on the weight of the monosaccharide raw materials) is called "wet sugar pyrolysis". The goal of wet monosaccharide pyrolysis may be to convert the aqueous monosaccharide raw materials into glycolaldehyde (2-hydroxyacetaldehyde), while forming other light oxygenated compounds (pyruvaldehyde, acetol, formaldehyde, and glyoxal), and minimizing the formation of other products.

[0054] The monosaccharide raw materials for wet monosaccharide pyrolysis are aqueous solutions of monosaccharides, the water content of which exceeds 15 wt.% based on the weight of the monosaccharide raw materials, such as exceeding 20 wt.%, exceeding 30 wt.%, exceeding 40 wt.%, exceeding 50 wt.%, exceeding 60 wt.%, exceeding 70 wt.%, or exceeding 80 wt.%. An example of a monosaccharide raw material for wet monosaccharide pyrolysis is a raw material containing 64 wt.% glucose, 1 wt.% maltose (disaccharide), and 35 wt.% water. Another example of a monosaccharide raw material for wet monosaccharide pyrolysis is a raw material containing 32 wt.% glucose, 31 wt.% fructose, 1.5 wt.% sucrose, and 35.5 wt.% water.

[0055] The water content of the monosaccharide raw materials for dry monosaccharide pyrolysis is less than 15 wt.% based on the weight of the monosaccharide raw materials. An example of a monosaccharide raw material for dry monosaccharide pyrolysis is glucose monohydrate (containing 91 wt.% monosaccharide and 9 wt.% water).

[0056] After the raw materials are pyrolyzed, the resulting pyrolysis products can be hydrogenated.

[0057] Hydrogenation refers to a chemical reaction between molecular hydrogen and another compound or element, which can optionally be carried out in the presence of a catalytic material and can also optionally be carried out in the presence of a solvent. In this process, glycolaldehyde can be formed by the pyrolysis of biomass, such as the pyrolysis of sugars. In this regard, the hydrogenation of the pyrolysis products will convert glycolaldehyde into ethylene glycol, optionally also convert glyoxal into ethylene glycol, pyruvaldehyde and acetol into propylene glycol, and formaldehyde into methanol, while minimizing the formation of other products as much as possible. The resulting composition can be referred to as a biomass-based composition.

[0058] Suitable hydrogenation catalysts comprise an active material supported on a carrier, the active material being selected from ruthenium, rhenium, rhodium, iridium, palladium, platinum, copper and nickel, or mixtures thereof; the carrier material is typically made of an inert material. Suitable carrier materials include carbon, silica, alumina, titanium dioxide and zirconia; or mixtures thereof.

[0059] In one aspect, the pyrolysis products are subjected to gas-phase hydrogenation in the presence of hydrogen and a hydrogenation catalyst. When the hydrogenation is gas-phase hydrogenation, the hydrogenation can be carried out in a temperature range of 200 °C to 250 °C and a hydrogen partial pressure range of 0.5 bar to 5 bar.

[0060] In one aspect, the pyrolysis products are subjected to liquid-phase hydrogenation in the presence of hydrogen and a hydrogenation catalyst. When the hydrogenation is liquid-phase hydrogenation, the hydrogenation can be carried out in a temperature range of 60 °C to 120 °C and a hydrogen partial pressure range of 20 bar to 200 bar. When the hydrogenation is liquid-phase hydrogenation, the partial pressure of hydrogen is the partial pressure in the gas phase above or dispersed in the hydrogenation liquid, and this partial pressure is proportional to the concentration of hydrogen in the liquid phase.

[0061] In one aspect, the hydrogenation is carried out in the presence of a solvent selected from water, methanol, ethanol, ethylene glycol and propylene glycol, and mixtures thereof.

[0062] Before hydrogenation, the pyrolysis products can be subjected to operations such as condensation and / or separation.

[0063] In one aspect, the total aldehyde concentration of the biomass-based composition is not less than 100 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is not less than 200 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is not less than 300 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is not less than 500 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is not less than 1000 ppm. "ppm" can be based on the weight of the biomass-based composition.

[0064] In one aspect, the total aldehyde concentration of the biomass-based composition is not greater than 1,000,000 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is not greater than 100,000 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is not greater than 10,000 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is not greater than 8,000 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is not greater than 5,000 ppm. "ppm" may be based on the weight of the biomass-based composition.

[0065] In one aspect, the total aldehyde concentration of the biomass-based composition is from 100 ppm to 1,000,000 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is from 200 ppm to 100,000 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is from 300 ppm to 10,000 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is from 500 ppm to 8,000 ppm. In one aspect, the total aldehyde concentration of the biomass-based composition is from 1,000 ppm to 5,000 ppm. "ppm" may be based on the weight of the biomass-based composition.

[0066] Solid acid catalyst and aldehyde removal resin

[0067] A method for purifying a biomass-based composition containing ethylene glycol includes (b) contacting the biomass-based composition with a solid acid catalyst and contacting the biomass-based composition with an aldehyde removal resin to provide a purified biomass-based composition. In this regard, the biomass-based composition may be contacted with the aldehyde removal resin after the solid acid catalyst. Alternatively, the biomass-based composition may be contacted with the solid acid catalyst and the aldehyde removal resin simultaneously (e.g., using a mixed bed containing the solid acid catalyst and the aldehyde removal resin, which may be referred to as a co-bed configuration).

[0068] In one aspect, the solid acid catalyst is placed in a first bed layer. The first bed layer may be disposed in a tower. In one aspect, the aldehyde removal resin is placed in a second bed layer. The second bed layer may be disposed in a tower. In one aspect, the second bed layer is located downstream of the first bed layer. The tower in which the first bed layer is disposed may be different from the tower in which the second bed layer is disposed. The tower in which the second bed layer is disposed may be the same as the tower in which the first bed layer is disposed.

[0069] As used herein, "downstream" (and "upstream") is with respect to the flow direction of the biomass-based composition. For example, if operation Y on the biomass-based composition occurs after operation X, it indicates that operation Y is located downstream of operation X.

[0070] In one aspect, the solid acid catalyst and the aldehyde removal resin are placed in a common bed (i.e., a mixed bed, also known as a co-bed configuration). The common bed can be disposed within a tower. Advantageously, it has been found that placing the solid acid catalyst and the aldehyde removal resin in a common bed is particularly effective. Without being limited by theory, it is believed that this arrangement helps to remove aldehydes as they are formed, which continuously promotes aldehyde formation.

[0071] The advantage of contacting the biomass composition with both the solid acid catalyst and the aldehyde removal resin simultaneously is that a high degree of aldehyde / ketone and acetal removal can be achieved in a single treatment. By reacting with the primary amine groups of the amine-containing resin, only free aldehydes and ketones are removed, while the corresponding acetals are not removed. Acetal hydrolysis is equilibrium-limited, which means that it is not possible to hydrolyze all acetals quantitatively thermodynamically without removing the corresponding reaction product aldehyde or ketone. In addition, acetal hydrolysis proceeds only at a relevant reaction rate in the presence of an acid catalyst.

[0072] These limitations can be overcome by using both a solid acid catalyst and an aldehyde removal resin simultaneously, where the aldehyde removal resin continuously removes free aldehydes or ketones, while the solid acid catalyst continuously catalyzes the hydrolysis of acetals to the corresponding free aldehydes and alcohols. However, a similar effect can also be achieved by passing the biomass-based composition sequentially through a series of repeated beds of the solid acid catalyst and beds of the aldehyde removal resin.

[0073] Those skilled in the art are able to select the operating conditions for contacting the biomass-based composition with the solid acid catalyst, as well as the operating conditions for contacting the biomass-based composition with the aldehyde removal resin.

[0074] In particular, within the capabilities of those skilled in the art, the steps of contacting the biomass-based composition with the solid acid catalyst and the steps of contacting the biomass-based composition with the aldehyde removal resin can be selected, such as the temperature, pressure, contact time, and space velocity.

[0075] In one aspect, one or each of contacting the biomass-based composition with the solid acid catalyst and contacting the biomass-based composition with the aldehyde removal resin is carried out at a temperature of 10 °C to 70 °C. In one aspect, one or each of contacting the biomass-based composition with the solid acid catalyst and contacting the biomass-based composition with the aldehyde removal resin is carried out at a temperature of 35 °C to 65 °C. In one aspect, one or each of contacting the biomass-based composition with the solid acid catalyst and contacting the biomass-based composition with the aldehyde removal resin is carried out at a temperature of 40 °C to 60 °C. In one aspect, one or each of contacting the biomass-based composition with the solid acid catalyst and contacting the biomass-based composition with the aldehyde removal resin is carried out at a temperature of 45 °C to 55 °C.

[0076] Solid acid catalyst

[0077] Solid acid catalysts have acidic functional groups. In one aspect, the acidic functional group is a sulfonic acid functional group.

[0078] In one aspect, the solid acid catalyst comprises an insoluble matrix (or support structure). The insoluble matrix can be porous.

[0079] In one aspect, the solid acid catalyst comprises a resin. In one aspect, the solid acid catalyst comprises a crosslinked resin. Non-limiting examples of crosslinked resins or polymers include: polystyrene crosslinked with divinylbenzene (styrene-divinylbenzene), and polyacrylic acid crosslinked with divinylbenzene (polyacrylic acid-divinylbenzene).

[0080] In one aspect, the solid acid catalyst comprises Amberlyst 15. Amberlyst 15 is a strongly acidic styrene-divinylbenzene resin having sulfonic acid functional groups. In one aspect, the solid acid catalyst comprises Amberlyst 131. Amberlyst 131 is a strongly acidic styrene-divinylbenzene resin having sulfonic acid functional groups. Those skilled in the art will understand that various types of solid acid catalysts can be used.

[0081] In one aspect, the solid acid catalyst is in particulate form.

[0082] In one aspect, the solid acid catalyst comprises zeolite.

[0083] Herein, "solid" can include semi-solids such as gels.

[0084] Aldehyde removal resin

[0085] The aldehyde removal resin removes aldehydes from the biomass-based composition at least in part.

[0086] In one aspect, the aldehyde removal resin comprises one or more of the following: primary amine functional groups; secondary amine functional groups; tertiary amine functional groups; and quaternary ammonium functional groups, such as quaternary ammonium bisulfite functional groups.

[0087] In one aspect, the aldehyde removal resin comprises an insoluble matrix (or support structure). The insoluble matrix can be porous.

[0088] In one aspect, the aldehyde removal resin is a heterogeneous resin. In one aspect, the aldehyde removal resin is solid or gel.

[0089] In one aspect, the aldehyde removal resin comprises a crosslinked resin. Non-limiting examples of crosslinked resins or polymers include: polystyrene crosslinked with divinylbenzene (styrene-divinylbenzene), and polyacrylic acid crosslinked with divinylbenzene (polyacrylic acid-divinylbenzene).

[0090] In one aspect, the aldehyde removal resin comprises Purolite A110. In one aspect, the aldehyde removal resin comprises Purolite A830. Purolite A110 is a weakly basic styrene-divinylbenzene resin with primary amine functional groups. Purolite A830 is a weakly basic polyacrylic acid-divinylbenzene resin with primary amine functional groups.

[0091] In one aspect, the aldehyde removal resin is in particulate form.

[0092] Further step

[0093] In certain aspects, the method for purifying a biomass-based composition comprises at least one further step.

[0094] In one aspect, the method comprises, after contacting the biomass-based composition with a solid acid catalyst and contacting the biomass-based composition with the aldehyde removal resin, further contacting the biomass-based composition with the aldehyde removal resin. This can be considered a "polishing" step, which further helps to remove aldehydes from the biomass-based composition. For example, this "polishing step" can be carried out after the biomass-based composition has been contacted with the solid acid catalyst and the aldehyde removal resin in a co-bed configuration or in a separate-bed configuration.

[0095] Distillation

[0096] In one aspect, the method for purifying a biomass-based composition comprises: subjecting the biomass-based composition to at least one distillation step to provide a distillation product, wherein the concentration of ethylene glycol in the distillation product is higher than that in the biomass-based composition.

[0097] In one aspect, the biomass-based composition subjected to at least one distillation step is aqueous.

[0098] As used herein, a "distillation product" can be a bottoms fraction or a distillate fraction. As used herein, a "bottoms fraction" (or "bottoms") can be considered the liquid fraction collected at the bottom of a distillation column during distillation. Those skilled in the art will understand that the components contained in the bottoms fraction are less volatile than the components of the distillate fraction. As used herein, a "distillate fraction" can be considered a vapor fraction withdrawn from any location above the bottom of the distillation column during distillation, a liquid fraction obtained by condensing the vapor, or a mixture of vapor and liquid. At least one distillate fraction is collected during distillation, but multiple distillate fractions can be collected from the distillation column simultaneously. Thus, a "liquid side draw" refers to a distillate fraction that is not collected from the top of the distillation column.

[0099] In one aspect, the biomass-based composition used in step (a) can be obtained by: (I) subjecting the biomass-based composition to at least one distillation step to provide a distillation product, wherein the concentration of ethylene glycol in the distillation product is higher than that in the biomass-based composition. This distillation product can be used as the biomass-based composition in step (a).

[0100] In one aspect, the method for purifying the biomass-based composition comprises the following steps: (c) subjecting the purified biomass-based composition obtained in step (b) to at least one distillation step to provide a distillation product, wherein the concentration of ethylene glycol in the distillation product is higher than that in the biomass-based composition, and this distillation product is a further purified biomass-based composition. This distillation step may involve removing water from the diluted composition in step (b). For example, this process can be achieved by evaporation using a rotary evaporator.

[0101] In one aspect, the content of ethylene glycol in the distillation product is not less than 85% by weight of the distillation product, for example not less than 90%, for example not less than 95%.

[0102] In one aspect, the content of ethylene glycol in the distillation product is not more than 99 wt.%, for example not more than 98 wt.%, for example not more than 97 wt.%.

[0103] In one aspect, the at least one distillation step includes a first distillation step, which comprises: feeding the biomass-based composition into a continuous distillation unit to provide a first bottom fraction and at least one first distillate fraction, wherein one of the first bottom fraction and the at least one first distillate fraction is an ethylene glycol-enriched fraction. This ethylene glycol-enriched fraction can be the distillation product.

[0104] In one aspect, the at least one distillation step further includes at least one further distillation step, which comprises: feeding the ethylene glycol-enriched fraction from the previous distillation step into a continuous distillation unit to provide a further bottom fraction and at least one further distillate fraction, wherein one of the further bottom fraction and the at least one further distillate fraction is an ethylene glycol-enriched fraction. This ethylene glycol-enriched fraction can be the distillation product.

[0105] Herein, "enriched" is relative to the composition being distilled. For example, the ethylene glycol-enriched fraction from the third distillation step has a higher ethylene glycol content compared to the ethylene glycol-enriched fraction from the second distillation step.

[0106] In one aspect, the ethylene glycol-enriched fraction from the first distillation step is also enriched in propylene glycol. This fraction refers to the ethylene glycol-enriched and propylene glycol-enriched fraction from the first distillation step.

[0107] In one aspect, the at least one distillation step includes a second distillation step that includes feeding an ethylene glycol-enriched fraction from a first distillation step to a continuous distillation unit to provide a second bottoms fraction and at least one second distillate fraction, wherein one of the second bottoms fraction and the at least one second distillate fraction is an ethylene glycol-enriched fraction. The ethylene glycol-enriched fraction can be a distillation product.

[0108] In one aspect, the at least one distillation step includes a second distillation step that includes feeding an ethylene glycol-enriched fraction and a propylene glycol-enriched fraction from a first distillation step to a continuous distillation unit to provide a second bottoms fraction and at least one second distillate fraction, wherein one of the second bottoms fraction and the at least one second distillate fraction is an ethylene glycol-enriched fraction. The ethylene glycol-enriched fraction can be a distillation product.

[0109] In one aspect, the at least one distillation step includes a third distillation step that feeds an ethylene glycol-enriched fraction from a second distillation step to a continuous distillation unit to provide a third bottoms fraction and at least one third distillate fraction, wherein one of the third bottoms fraction and the at least one third distillate fraction is an ethylene glycol-enriched fraction. The ethylene glycol-enriched fraction can be a distillation product.

[0110] In one aspect, the at least one distillation step includes a fourth distillation step that feeds an ethylene glycol-enriched fraction from a third distillation step to a continuous distillation unit to provide a fourth bottoms fraction and at least one fourth distillate fraction, wherein one of the fourth bottoms fraction and the at least one fourth distillate fraction is an ethylene glycol-enriched fraction. The ethylene glycol-enriched fraction can be a distillation product.

[0111] In one aspect, in the at least one distillation step (in this case, referring to the complete distillation process), at least 80 wt.%, such as at least 85 wt.%, such as at least 90 wt.%, such as at least 92 wt.%, such as at least 95 wt.%, such as at least 97.5 wt.%, such as at least 99 wt.%, such as at least 99.5 wt.% of the non-ethylene glycol components (i.e., all components that are not ethylene glycol) are removed from the biomass-based composition based on the weight of the biomass-based composition.

[0112] For a specific distillation process, the distribution ratio of the feed between the top and bottom of the column is controlled by: feed rate, reflux ratio, reboiler energy input, feed preheating degree, input amount of the cooling medium for the reflux and the distillation condenser, column pressure and separation ability, and the vapor-liquid equilibrium of the components in the feed.

[0113] Components with higher volatility than ethylene glycol can be concentrated and removed as distillate, while the concentrated ethylene glycol product can be collected as the bottom fraction. Alternatively, components with lower volatility than ethylene glycol can be concentrated and removed as the bottom fraction, while the concentrated ethylene glycol product can be collected as the distillate.

[0114] In the field of distillation technology, those skilled in the art are familiar with how to design distillation steps to obtain a bottom fraction enriched in ethylene glycol or a distillate fraction enriched in ethylene glycol.

[0115] Melt crystallization

[0116] In one aspect, the method for purifying the biomass-based composition includes performing at least one melt crystallization step on the distillation product to form crystals and mother liquor, such that the crystals provide the purified biomass-based composition, wherein the concentration of ethylene glycol in the purified biomass-based composition is higher than that in the distillation product.

[0117] Further treatment step

[0118] Before distilling off the water, optional further treatment steps can be employed. This includes passing the purified biomass-based composition containing ethylene glycol through a column containing an aldehyde removal resin bed. For example, this can be (Purolite A110) at a temperature of 50 °C. It has been found that the further treatment step can further reduce the coloring of the polyester particles.

[0119] Purified biomass-based composition

[0120] In one aspect, the purified biomass-based composition in step (b) of the method for purifying the biomass-based composition is provided by contacting the biomass-based composition in step (a) of the method for purifying the biomass-based composition with a solid acid catalyst and an aldehyde removal resin. In one aspect, the biomass-based composition in step (b) of the method for purifying the biomass-based composition is provided by at least one distillation step. In one aspect, the purified biomass-based composition is provided by at least one melt crystallization step. Thus, for example, in step (b) of the method for purifying the biomass-based composition, the purified biomass-based composition can be a further purified biomass-based composition from at least one distillation step or a further purified biomass-based composition from at least one melt crystallization step. The purified biomass-based composition in step (b) of the method for purifying the biomass-based composition may hereinafter be referred to as the "purified biomass-based composition".

[0121] In one aspect, the total aldehyde concentration of the purified biomass-based composition is not greater than 50 ppm. In one aspect, the total aldehyde concentration of the purified biomass-based composition is not greater than 20 ppm. In one aspect, the total aldehyde concentration of the purified biomass-based composition is not greater than 18 ppm. In one aspect, the total aldehyde concentration of the purified biomass-based composition is not greater than 15 ppm. In one aspect, the total aldehyde concentration of the purified biomass-based composition is not greater than 10 ppm. "ppm" may be based on the weight of the purified biomass-based composition.

[0122] In one aspect, the total aldehyde concentration of the purified biomass-based composition is not less than 1 ppm. In one aspect, the total aldehyde concentration of the purified biomass-based composition is not less than 2 ppm. In one aspect, the total aldehyde concentration of the purified biomass-based composition is not less than 5 ppm. In one aspect, the total aldehyde concentration of the purified biomass-based composition is not less than 10 ppm. "ppm" may be based on the weight of the purified biomass-based composition.

[0123] In one aspect, the purified biomass-based composition is characterized by an APHA color value (measured according to ASTM D1209-05) of not greater than 10 mg / L PtCo. In one aspect, the purified biomass-based composition is characterized by an APHA color value (measured according to ASTM D1209-05) of not greater than 9 mg / L PtCo. In one aspect, the purified biomass-based composition is characterized by an APHA color value (measured according to ASTM D1209-05) of not greater than 8 mg / L PtCo. In one aspect, the purified biomass-based composition is characterized by an APHA color value (measured according to ASTM D1209-05) of not greater than 7 mg / L PtCo. In one aspect, the purified biomass-based composition is characterized by an APHA color value (measured according to ASTM D1209-05) of not greater than 6 mg / L PtCo. In one aspect, the purified biomass-based composition is characterized by an APHA color value (measured according to ASTM D1209-05) of not greater than 5 mg / L PtCo.

[0124] The American Public Health Association (APHA) color standard, also known as the Hazen color scale or platinum-cobalt (PtCo) color scale, is a method for measuring the color of liquid chemicals. This color scale is used to evaluate the quality of chemicals and other substances and can well measure the level of impurities affecting color, such as in biomass-based compositions containing ethylene glycol.

[0125] In this article, the APHA color value is measured according to ASTM D1209-05 at 20 °C to 25 °C (room temperature) and atmospheric pressure.

[0126] APHA color values can also be used to evaluate the thermal stability of liquid chemicals through the "APHA color after heating" test. In this document, this is done by performing a heating step of heating the liquid chemical to 200 degrees for a relatively long period of time. In the present invention, 2 to 4 hours is suitable. After cooling to room temperature, the APHA color value is measured. The APHA color value can be used as an indicator of the thermal stability of the liquid. A higher APHA color value may indicate that the substance has degraded or reacted to form colored impurities during heating.

[0127] Unless otherwise specified herein, APHA color refers to the test result of a purified biomass-based composition without the heating step. If the heating step has been performed, it is labeled as "APHA color after heating".

[0128] We unexpectedly found that even if the ethylene glycol composition does not meet the industrial specifications in terms of UV transmittance at 220 nm, 275 nm, and 350 nm, it may still reach polymer grade. It was found that an APHA color before heating of less than 5 mg / L PtCo and an APHA color after heating of less than 20 mg / L PtCo are good indicators for determining whether an ethylene glycol composition can reach polymer grade / suitable for producing colorless PET. It is more desirable if the APHA color after heating can be controlled below 15 mg / L.

[0129] Therefore, thermal stability / APHA color after heating can be used as an indicator to measure whether a purified biomass-based composition containing ethylene glycol is suitable as an ethylene glycol reactant in PET synthesis. In one embodiment according to the present invention, the APHA color after heating of a purified biomass-based composition containing ethylene glycol that is considered suitable as a PET synthesis reactant is less than 20 mg / L PtCo. In one embodiment, according to the present invention, the APHA color after heating of a purified biomass-based composition containing ethylene glycol that is considered suitable as a PET synthesis reactant is less than 15 mg / L PtCo.

[0130] In one aspect, the purified biomass-based composition is characterized in that the APHA color value (measured according to ASTM D1209-05) is greater than 0 mg / L PtCo, and this can be considered as the lower limit of any upper limit mentioned herein.

[0131] In one aspect, the content of ethylene glycol in the purified biomass-based composition is not less than 98 wt.% based on the weight of the purified biomass-based composition. In one aspect, the content of ethylene glycol in the purified biomass-based composition is not less than 99 wt.% based on the weight of the purified biomass-based composition. In one aspect, the content of ethylene glycol in the purified biomass-based composition is not less than 99.25 wt.% based on the weight of the purified biomass-based composition. In one aspect, the content of ethylene glycol in the purified biomass-based composition is not less than 99.5 wt.% based on the weight of the purified biomass-based composition.

[0132] In one aspect, the content of ethylene glycol in the purified biomass-based composition is not greater than 99.95 wt.% based on the weight of the purified biomass-based composition. In one aspect, the content of ethylene glycol in the purified biomass-based composition is not greater than 99.9 wt.% based on the weight of the purified biomass-based composition. The purified biomass-based composition has an absolute upper limit of 100 wt.% of ethylene glycol based on the weight of the purified biomass-based composition.

[0133] In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is less than 40%.

[0134] The UV transmittance can be used as a simple indicator to measure the presence of low-concentration impurities in ethylene glycol, which will have an adverse effect on the color of PET prepared therefrom, that is, a higher transmittance means fewer impurities. When removing low-concentration impurities from ethylene glycol, the purity of ethylene glycol will increase due to the removal of impurities. So far, the generally accepted view in the field of the present invention is that an ethylene glycol composition needs to have a high UV transmittance to be used in the production of polyesters with acceptable polymer quality. This view is particularly applicable in bottle manufacturing, such as the manufacture of polyethylene terephthalate bottles. The purification of biomass-based ethylene glycol to obtain a high UV transmittance may be costly and complex, and may even be impossible to achieve at all (see, for example, WO2015 / 028156, WO 2018 / 089600, and WO 2018 / 089605). This situation of being unable to economically provide biomass-based ethylene glycol that meets the UV transmittance specifications has been a major obstacle to providing a more sustainable raw material for polyester preparation. We have surprisingly found that even if the UV transmittance of biomass-based ethylene glycol does not meet the industrial specification requirements, it is still possible to produce satisfactory "bottle-grade" polyester using biomass-based ethylene glycol with a low UV transmittance.

[0135] In this article, the UV transmittance at 275 nm is measured according to ASTM method E2193-16 in the temperature range of 20 °C to 25 °C and at atmospheric pressure.

[0136] In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not more than 38%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not more than 35%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not more than 32%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not more than 30%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not more than 28%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm is not more than 25%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not more than 22%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not more than 20%.

[0137] In one aspect, the UV transmittance of the biomass-based composition to be contacted with at least one reagent at 275 nm (measured according to ASTM method E219) is not less than 0%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not less than 1%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not less than 2%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not less than 5%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not less than 8%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not less than 10%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not less than 12%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is not less than 15%.

[0138] In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is between 0% and 40%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is 1% to 38%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is 2% to 38%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is 5% to 35%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is 10% to 35%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is 15% to 35%. In one aspect, the UV transmittance of the purified biomass-based composition at 275 nm (measured according to ASTM method E2193-16) is 20% to 35%.

[0139] According to one embodiment of the present invention, the APHA colority of the purified glycol-containing biomass-based composition, which is considered suitable as a PET synthesis reactant, after heating is less than 20 mg / L PtCo. In one embodiment, the APHA colority of the purified glycol-containing biomass-based composition, which is considered suitable as a PET synthesis reactant according to the present invention, after heating is less than 15 mg / L PtCo.

[0140] Composition

[0141] According to another aspect of the present invention, there is provided a purified biomass-based composition obtained by a method of purifying a biomass-based composition according to one aspect of the present invention.

[0142] According to another aspect of the present invention, there is provided a purified biomass-based composition obtained by the method of purifying a biomass-based composition in the above aspect of the present invention, wherein the purified biomass-based composition is characterized in that the APHA colority after heating measured according to ASTM D1209-05 is less than 20 mg / L PtCo, and the UV transmittance at 275 nm measured according to ASTM method E2193-16 is less than 40%.

[0143] According to another aspect of the present invention, there is provided a purified biomass-based composition obtained by the method for purifying a biomass-based composition of the above aspect of the present invention, wherein the purified biomass-based composition is characterized in that the APHA colority after heating as measured according to ASTM D1209-05 is less than 15 mg / L PtCo, and the UV transmittance at 275 nm as measured according to ASTM method E2193-16 is less than 40%.

[0144] Use

[0145] According to another aspect of the present invention, there is provided the use of a purified biomass-based composition obtained by the method for purifying a biomass-based composition according to one aspect of the present invention in the production of a polyester.

[0146] The polyester may include polyethylene terephthalate.

[0147] Polyester production

[0148] According to another aspect of the present invention, there is provided a method for producing a polyester, the method comprising contacting a purified biomass-based composition obtained by the method for purifying a biomass-based composition according to one aspect of the present invention with at least one reagent to form a polyester.

[0149] In one aspect, contacting a purified biomass-based composition obtained by the method for purifying a biomass-based composition with at least one reagent includes: (I) reacting ethylene glycol with at least one reagent to provide monomers; and (II) polymerizing the monomers to provide a polyester. However, for the sake of clarity, the polyester may be polymerized by any suitable method to obtain the desired polyester properties.

[0150] In one aspect, the at least one reagent comprises one or more of a dicarboxylic acid, a diester, and an acid anhydride.

[0151] In one aspect, the dicarboxylic acid is a terephthalic acid compound, an isophthalic acid compound, or a mixture thereof.

[0152] In one aspect, the dicarboxylic acid is of renewable origin. For example, the dicarboxylic acid may be prepared by a synthetic route from biomass-derived starting materials such as furfural.

[0153] In one aspect, the terephthalic acid compound is selected from terephthalic acid, dimethyl terephthalate, or a combination thereof.

[0154] In one aspect, the isophthalic acid compound is selected from isophthalic acid, dimethyl isophthalate, or a combination thereof.

[0155] In one aspect, the diacid is selected from naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, succinic acid, glutaric acid, furandicarboxylic acid, adipic acid, azelaic acid, sebacic acid, and combinations thereof.

[0156] In one aspect, the monomer includes bis(2-hydroxyethyl) terephthalate monomer.

[0157] The polyester may include polyethylene terephthalate. In one aspect, contacting the purified biomass-based composition obtained by a method of purifying a biomass-based composition with at least one reagent includes: (I) reacting ethylene glycol with one or more diacids and diesters to provide bis(2-hydroxyethyl) terephthalate monomer; and (II) polymerizing the monomer to provide a polyester comprising polyethylene terephthalate. In one aspect, step (I) is carried out at a temperature of 230 °C to 260 °C. In one aspect, step (II) is carried out at a temperature of 270 °C to 300 °C. In one aspect, step (II) is carried out in the presence of a catalyst. In one aspect, the catalyst is a heterogeneous catalyst. In one aspect, the catalyst is an antimony-containing catalyst, a platinum-containing catalyst, a titanium-containing catalyst, an aluminum-containing catalyst, or a germanium-containing catalyst. In one aspect, the catalyst is antimony(III) oxide. In one aspect, step (II) of the polyester production method is carried out in the presence of a phosphorus compound added as a stabilizer.

[0158] When the content of the ethylene glycol component of the diol in the polyester is higher than 90%, and the content of the terephthalic acid component of the diacid in the polyester is higher than 90%, the polyester is considered to be polyethylene terephthalate (PET).

[0159] In one aspect, step (I) of reacting ethylene glycol with at least one reagent to provide the monomer can be carried out in the presence of a small amount of other diols. In the present application, "a small amount" preferably means less than 40 mol% of the total molar amount of the diols.

[0160] In one aspect, the other diols are selected from diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2-methyl-1,4-pentanediol, 3-methyl-2,4-pentanediol, trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,2-diethyl-1,3-propanediol, 1,3-hexanediol, 1,4-bis(hydroxyethoxy)benzene, 2,2-bis(4-hydroxycyclohexyl)propane, 2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane, 2,2-bis(3-hydroxyethoxyphenyl)propane, 2,2-bis(4-hydroxypropoxyphenyl)propane, and cyclohexanedimethanol, or mixtures thereof.

[0161] Polymerization conditions can produce polymerization grades with different molecular weights. Traditionally, polymers with different molecular weights are characterized by the intrinsic viscosity (IV) value, which is measured according to ASTM D792.

[0162] In one aspect, a solid state polymerization (SSP) reaction can be further carried out on the polyester. The reaction is carried out in an inert or low-pressure atmosphere at a temperature in the range of 180 to 230 °C for a certain period of time to obtain the desired IV value. In one aspect, the IV after SSP is at least 0.65 dL / g. In one aspect, the IV after SSP is at least 0.75 dL / g. In one aspect, the IV after SSP is at least 0.85 dL / g. In one aspect, the IV after SSP is at least 1.0 dL / g.

[0163] Polyester

[0164] According to another aspect of the present invention, there is provided a polyester obtained by the method for producing a polyester according to one aspect of the present invention.

[0165] In one aspect, the polyester composition disclosed herein may further comprise additives in addition to the polyester. The additives may include, but are not limited to, colorants, ultraviolet (UV) stabilizers, antioxidants, fillers, gas barrier agents, plasticizers, nucleating agents, heat stabilizers, chain extenders, and combinations thereof.

[0166] Known methods can be used to incorporate the additives into the polyester composition described herein. For example, the additives can be introduced before, during, or after the polymerization step. The additives can also be compounded with the polyester in subsequent processing or conversion steps.

[0167] In one aspect, the polyester and its products according to one or more embodiments can be recycled under standard recycling operating conditions by conventional recycling methods known to those of ordinary skill in the art, such as mechanical recycling and chemical recycling. In one or more embodiments, the packaging products produced using the polyester described herein are mechanically recycled in the form of fragments or pellets. Therefore, the resulting fragments and pellets generally still retain the bio-based carbon content that can be measured by 14 the C detection method and ASTM D6866. Using the processing and manufacturing techniques described herein, the resulting fragments or pellets can be reprocessed into the same or different polyester-based packaging products. The reprocessing can be carried out simultaneously with PET from conventional petrochemical sources (fossil fuels or non-bio-based sources), or fragments and pellets obtained by recycling conventional polyesters, but is not limited thereto.

[0168] In one aspect, the polyester is characterized in that the L* CIELAB color space parameter value (measured according to ASTM method D6290-19) is not less than 65. In one aspect, the polyester is characterized in that the L* CIELAB color space parameter value (measured according to ASTM method D6290-19) is not less than 70. In one aspect, the polyester is characterized in that the L* CIELAB color space parameter value (measured according to ASTM method D6290-19) is not less than 75. In one aspect, the polyester is characterized in that the L* CIELAB color space parameter value (measured according to ASTM method D6290-19) is not less than 80. In one aspect, the polyester is characterized in that the L* CIELAB color space parameter value (measured according to ASTM method D6290-19) is not less than 85. In one aspect, the polyester is characterized in that the L* CIELAB color space parameter value (measured according to ASTM method D6290-19) is not less than 90.

[0169] In this article, the CIELAB color space parameter value is measured according to ASTM D6290-19 at 20 °C to 25 °C (room temperature) and atmospheric pressure.

[0170] In one aspect, the polyester is characterized in that the a* CIELAB color space parameter value (measured according to ASTM method D6290-19) is from -4 to 4. In one aspect, the polyester is characterized in that the a* CIELAB color space parameter value (measured according to ASTM method D6290-19) is from -3 to 3. In one aspect, the polyester is characterized in that the a* CIELAB color space parameter value (measured according to ASTM method D6290-19) is from -2 to 2.

[0171] In one aspect, the polyester is characterized in that the b* CIELAB color space parameter value (measured according to ASTM method D6290-19) is from -4 to 4. In one aspect, the polyester is characterized in that the b* CIELAB color space parameter value (measured according to ASTM method D6290-19) is from -3 to 3. In one aspect, the polyester is characterized in that the b* CIELAB color space parameter value (measured according to ASTM method D6290-19) is from -2 to 2.

[0172] The polyester may include polyethylene terephthalate.

[0173] Packaging article or preform

[0174] According to another aspect of the present invention, there is provided a packaging article or preform made of the polyester according to one aspect of the present invention.

[0175] The polyesters according to the present disclosure can be formulated for a variety of polymer articles and products. Polyester articles can include, but are not limited to, containers, flasks, bottles, utensils, receptacles, bottle caps, carpets, clothing, fabrics, strapping tapes, ropes, stuffing fibers, building materials, furniture, medical supplies, films, sheets, laminates, protective packaging, electronic enclosures, solenoid valves, smart meters, photovoltaic components, solar junction boxes, automotive parts, wiper arms and gearbox housings, headlamp mounts, hoods, connector housings, industrial fibers, 3D printing filaments, thermoformed articles, etc.

[0176] As previously mentioned, one of the applications of the polyester according to one or more embodiments is a film. Specifically, the polyester film applications can be uniaxially oriented films, biaxially oriented films, multi-layer films composed of other polymeric materials, blown films, articles, or extrusion coatings. The blown articles can be extrusion blow molding, stretch blow molding, or injection blow molding.

[0177] In one or more embodiments, the polyester can be used to produce polyester fibers by melt spinning and / or drawing. Polyester fibers include, but are not limited to, drawn textured yarns, partially oriented yarns, polyester staple fibers, fully drawn yarns, spun-drawn yarns, and polyester meshes.

[0178] The manufacturing processes can include, but are not limited to: injection molding, stretch blow molding, lamination, extrusion, thermoforming, melt spinning, and 3D printing.

[0179] In one aspect, the packaging article is a container. In one aspect, the polyester container can be used for, but is not limited to, packaging food, cosmetics, soft drinks, water, alcoholic beverages, cosmetics, pharmaceuticals, and edible oils.

[0180] In one aspect, the packaging article is a bottle.

[0181] The polyester can include polyethylene terephthalate.

[0182] Total aldehyde concentration

[0183] The total aldehyde concentration can be determined by any suitable technique known to those skilled in the art. For example, in one aspect, the total aldehyde concentration is determined using ASTM method E2313-20. Aldehydes can exist in the form of acetals and free aldehydes.

[0184] Ethylene glycol concentration

[0185] The ethylene glycol concentration can be determined by any suitable technique known to those skilled in the art. In one aspect, the ethylene glycol concentration is determined using flame ionization detection (FID) gas chromatography (referred to herein as "GC-FID").

[0186] General aspect

[0187] According to a general aspect of the present invention, there is provided a method for purifying a biomass-based composition containing ethylene glycol, the method comprising: (a) providing a biomass-based composition containing water, wherein the content of the water is at least 0.1 wt.% based on the weight of the biomass-based composition; and (b) contacting the biomass-based composition with a solid acid catalyst and / or contacting the biomass-based composition with an aldehyde removal resin to provide a purified biomass-based composition. The features of the method for purifying a biomass-based composition according to the general aspect may include any features of the method for purifying a biomass-based composition according to any other aspect.

[0188] Any aspect of the present disclosure may be defined according to any other aspect of the present disclosure. For example, one aspect of the present disclosure may include any features of any other aspect of the present disclosure. For example, the features of one aspect of the present disclosure may be defined according to the features of any other aspect of the present disclosure. Examples

[0189] Example 1: GC analysis

[0190] In all examples, GC analysis was performed on an Agilent 7890A GC equipped with an FID and a PolyARC reactor (PolyARC from: Activated Research Company, 7561 Corporate Way, Eden Prairie, MN 55344, USA). The PolyARC reactor converts all analytes to methane before quantification. Helium was used as the carrier gas and the make-up gas for the FID. Air and H2 were supplied to the PolyARC electronic flow control module and the FID. The samples were injected directly without any pretreatment. The effluent of the GC column was directly introduced into the inlet of the PolyARC reactor. The reactor effluent was directly connected to the FID. GC conditions: forward injection port split ratio 15:1; injection port temperature 230 °C; column: DB-624 (60 m × 0.32 mm × 1.8 μm); carrier gas (He): 2 ml / min; injection volume: 0.5 μL. FID conditions: temperature 300 °C;

[0191] H2: 1.5 ml / min; air: 350 ml / min; make-up gas (He): 28 ml / min. PolyARC reactor conditions: temperature 450 °C; H2: 35 ml / min; air: 2.5 ml / min. The oven initial temperature was 100 °C. After injection, the temperature was raised to 125 °C at 1.5 °C / min and held for 5 minutes. Then, the temperature was raised to 260 °C at 20 °C / min and held for 10 minutes. Chromatograms were obtained and analyzed as needed. Unless otherwise specified, quantitative analysis was based on peak area.

[0192] Example 2 - Biomass-based composition

[0193] As described in Example 1 of WO 2017 / 216311, a mixture of C1-C3 oxygenates is obtained by pyrolytic cracking of an aqueous solution of sugar (glucose). As described in Example 4 of US 9,926,247, the C1-C3 oxygenate mixture is hydrotreated to obtain a hydrotreated product composition. The hydrotreated product composition thus obtained is subjected to a condensation treatment to obtain an aqueous ethylene glycol solution (biomass-based composition containing ethylene glycol).

[0194] Example 3 - Distillation

[0195] After distillation of the aqueous ethylene glycol solution provided in Example 2, the ethylene glycol concentration is 99.7 wt.% based on the weight of the aqueous solution (determined by GC-FID analysis, see Example 1).

[0196] The distillation unit used in this experiment is a continuous distillation unit, which includes a packed column (column diameter 50 mm; filled with 4 m of Sulzer DX structured packing), and the feed inlet is located in the middle of the column body. The reboiler of this distillation unit is a wiped film heat exchanger. The bottom fraction is collected as a liquid product from the outlet of the wiped film heat exchanger. At the top of the column, a water-cooled condenser fully condenses the steam in the column. The condensate is divided into two parts according to the reflux ratio: the reflux fraction returns to the top of the column in liquid form, and the remaining part is collected as the distillate fraction. The liquid side stream is collected through a liquid side stream sampling port located 1 m below the top of the column.

[0197] The distillation and purification process is carried out in series by three-stage continuous vacuum distillation.

[0198] In the first distillation step, the aqueous ethylene glycol solution is distilled under the conditions of a pressure of 200 mBar and a reflux ratio of 4. Water and by-products more volatile than propylene glycol are removed as the distillate fraction. The bottom fraction is enriched in ethylene glycol.

[0199] In the second distillation step, the bottom fraction of the first distillation is distilled under the conditions of a pressure of 200 mBar and a reflux ratio of 20. Propylene glycol and 1,2-butanediol are completely removed as distillates. The bottom fraction is enriched in ethylene glycol and is the distillation product of this distillation process.

[0200] In the third distillation step, the bottom fraction of the second distillation is distilled under the conditions of a pressure of 200 mBar and a reflux ratio of 24. The distillation product stream, i.e., the distillate fraction containing 99.7 wt.% ethylene glycol, is collected by liquid side stream sampling. The composition of this product stream is "distillation product". The mass ratio of the distillate to the feed is 0.13, and the mass ratio of the liquid side stream to the feed is 0.6.

[0201] Example 4a - Acid catalyst and resin treatment purification under diluted conditions (method of the present invention) )

[0202] The distillate of Example 3 was processed. The processing included:

[0203] (1) Dilute the distillate to form a diluted composition such that the water content of the diluted composition is about 20 wt.% based on the weight of the diluted composition;

[0204] (2) Pass the diluted composition through a column containing a mixed bed of solid acid catalyst resin (Amberlyst 15) and aldehyde removal resin (Purolite A110) at a temperature of 50 °C; then

[0205] (3) Remove water from the diluted composition by evaporation on a rotary evaporator. The water was evaporated at a pressure of 70 mBar by immersing the rotating distillation flask in a heated oil bath at a temperature of 150 °C. Evaporation was stopped when the water content of the ethylene glycol product fraction in the distillation flask reached 2 wt.%.

[0206] This product was designated as the "acid catalyst and resin treated" product 4a.

[0207] Example 4b - Acid catalyst and resin treatment purification under non-diluted conditions (method of the present invention)

[0208] The distillate of Example 3 contained about 0.3 wt.% water and was subjected to treatment. The treatment included:

[0209] (i) Pass the distillate stream through a column containing a mixed bed of solid acid catalyst resin (Amberlyst 15) and aldehyde removal resin (Purolite A110) at a temperature of 50 °C;

[0210] This product was designated as the "acid catalyst and resin treated" product 4b.

[0211] Example 4c - Resin treatment purification under diluted conditions (comparative example)

[0212] The distillate of Example 3 was processed. The processing included:

[0213] (1) Dilute the distillate to form a diluted composition such that the water content of the diluted composition is about 20 wt.% based on the weight of the diluted composition;

[0214] (2) Pass the diluted composition through a column containing aldehyde removal resin (Purolite A110) at a temperature of 50 °C; then

[0215] (3) The water is removed from the diluted composition by evaporation on a rotary evaporator. The water is evaporated at a pressure of 70 mBar by immersing the rotating distillation flask in a heated oil bath at 150 °C. Evaporation is stopped when the water content in the ethylene glycol product fraction in the distillation flask reaches 2 wt.%.

[0216] This product is called the "resin-treated" product 4c.

[0217] Example 5 - Analysis of "distillation product" and "acid catalyst and resin treatment product"

[0218] The distillation products prepared in Example 3, the catalysts prepared in Examples 4a and 4b, and the resin-treated product were evaluated in terms of parameters relevant to polyesters (such as PET production). This included measuring: the concentration of diethylene glycol (wt.%); the APHA color (mg / L PtCo); and the APHA color (mg / L PtCo) after heating to 200 °C and holding for 4 hours.

[0219] The quantitative analysis of ethylene glycol was carried out according to the method described in Example 1.

[0220] The standard method for the determination of diethylene glycol concentration is described in ASTM E2409-20a.

[0221] The standard method for the determination of APHA color is described in ASTM method D1209-05. Herein, the APHA color measurement (according to ASTM method D1209-05) is carried out by an instrumental method built into a Lovibond PFX-I series spectrophotocolorimeter. This method is called Pt-Co D1209. The APHA color is measured using a 100 mm glass cuvette to hold the sample. The measurement is carried out at 20 °C to 25 °C (room temperature) and atmospheric pressure. A standard curve covering the relevant color range is prepared by volume-based dilution of a commercially available Pt-Co standard solution (for example, the Pt-Co / Hazen / APHA color reference standard available from Sigma Aldrich, Sigma number 134190 (ASTM color 100)) with softened water. The APHA value of a given sample is determined according to the standard curve from the Pt-Co value measured for the sample. That is, the given sample is put into the colorimeter for testing, and the Pt-Co value output by the colorimeter is compared with the standard curve to determine the APHA color value of the given sample.

[0222] The heat treatment steps for ethylene glycol samples before measurement are as follows: Each sample is placed in a glass container, and the sample is flushed with nitrogen for 15 minutes to remove air. The glass container is sealed, and there is basically no oxygen in the container. The corresponding sample in the glass container is heated to 200 °C and maintained for four hours. After cooling, the color of the heat-treated sample is determined using the above-mentioned APHA colorimetric method.

[0223] Table 1 shows the measurement results.

[0224]

[0225] As shown in Table 1, the APHA colorities of products 4a, 4b, and 4c are relatively low, all less than 5 mg / L PtCo. However, only the APHA colorities of products 4a and 4b (obtained according to the method of the present invention) after heating are acceptable, less than 20 mg / L PtCo.

[0226] Example 6 - Polyester production

[0227] In their respective experiments, the distilled product prepared in Example 3 and the catalyst and resin-treated product prepared in Example 4 were used to produce polyester. Each experiment was carried out as a standard batch process. Each experiment involved contacting the respective product with terephthalic acid to produce a polyester containing polyethylene terephthalate (PET). Isophthalic acid (IPA) was added as a comonomer compound to the corresponding product, accounting for 2% of the total dibasic acid compound. This process was carried out in two steps: (1) contacting terephthalic acid with the corresponding product to carry out an esterification reaction, during which bis(2-hydroxyethyl) terephthalate was formed, and water and volatile by-products were removed; (2) polymerizing (polycondensing) bis(2-hydroxyethyl) terephthalate in the presence of an antimony catalyst while continuously removing the released ethylene glycol.

[0228] Step (1) was carried out at atmospheric pressure in the temperature range of 150 °C to 260 °C. Step (2) was carried out under vacuum (0.01 to 2 mbar) in the temperature range of 280 °C to 300 °C.

[0229] Step (2) was continuously carried out until the target degree of polymerization was confirmed by the determination of the intrinsic viscosity. The standard method for determining the intrinsic viscosity is described in ASTM method D4603-18.

[0230] The degree of polycondensation can also be indirectly approximated by measuring the torque on the stirrer shaft of the mixer in the polymerization reactor. This requires preparation of a standard curve for the relationship between torque and intrinsic viscosity. This method is used to control the duration of polycondensation. Once the required torque on the stirrer shaft is reached, the melt of the polymeric material is removed from the polymerization vessel and transferred to an ice-water cooling bath to stop the reaction. The intrinsic viscosity values listed in Table 4 are actual measured values of the polyester product obtained from polycondensation. After cooling, the polymeric material is divided into pellets.

[0231]

[0232]

[0233] As described herein, the L*, a*, and b* parameter values are CIELAB color components. The L* value represents perceived lightness, with black being 0 and white being 100. The a* and b* values represent the four colors of human vision: red, green, blue, and yellow. A positive b* value represents yellow. As the b* value approaches 0, the degree of yellow decreases.

[0234] As shown in Table 2, a* is essentially not affected by the acid catalyst and the resin treatment step. In contrast, after the melt crystallization step, b* is significantly closer to zero. The color of the polyester pellets made from the distillation product is unacceptable for producing bottle-grade PET (i.e., PET for producing drinking water and soft drink bottles). The color of the polyester pellets made from the acid catalyst and the resin treatment product is acceptable and can be used to produce bottle-grade PET.

[0235] The various embodiments described herein are only intended to aid in understanding and teaching the claimed features. These embodiments are provided only as representative samples, and their content is not exhaustive and / or exclusive. It should be understood that the advantages, embodiments, examples, functions, features, structures, and / or other aspects described herein should not be considered as limiting the scope of the invention defined by the claims, nor as limiting the equivalents of the claims, and other embodiments can be utilized and modified without departing from the scope of the claimed invention. The various embodiments of the invention may suitably comprise, consist of, or consist essentially of a suitable combination of the disclosed elements, components, features, parts, steps, means, etc., rather than being limited to what is specifically described herein. Additionally, the present disclosure may include other inventions that are not currently claimed but may be claimed in the future.

Claims

1. A method for purifying a biomass-based composition comprising ethylene glycol, the method comprising: (a) providing a biomass-based composition comprising water, wherein the water content is at least 0.1 wt.% based on the weight of the biomass-based composition; and (b) contacting the biomass-based composition with a solid acid catalyst and contacting the biomass-based composition with an aldehyde removal resin to provide a purified biomass-based composition.

2. The method according to claim 1, wherein the solid acid catalyst comprises a sulfonic acid functional group.

3. The method according to claim 1 or 2, wherein the solid acid catalyst comprises one or more of a resin and a zeolite.

4. The method according to any one of claims 1 to 3, wherein the aldehyde removal resin comprises one or more of the following: a primary amine functional group, a secondary amine functional group, a tertiary amine functional group, and a quaternary ammonium functional group, such as a quaternary ammonium bisulfite functional group.

5. The method according to any one of claims 1 to 4, wherein based on the weight of the purified biomass-based composition, the total aldehyde concentration of the purified biomass-based composition does not exceed 50 ppm, such as does not exceed 20 ppm, such as does not exceed 18 ppm, such as does not exceed 15 ppm, such as does not exceed 10 ppm.

6. The method according to any one of claims 1 to 5, wherein based on the weight of the biomass-based composition, the total aldehyde concentration of the biomass-based composition in step (a) is not less than 100 ppm, such as not less than 200 ppm, such as not less than 300 ppm, such as not less than 500 ppm, such as not less than 1000 ppm.

7. The method according to any one of claims 1 to 6, wherein the solid acid catalyst and the aldehyde removal resin are disposed in a common bed.

8. The method according to any one of claims 1 to 7, wherein the purified biomass-based composition is characterized in that its APHA color value, as determined according to ASTM D1209-05, is not greater than 5 mg / L PtCo.

9. The method according to any one of claims 1 to 8, wherein the purified biomass-based composition is characterized in that its APHA color value after heating, as determined according to ASTM D1209-05, is not greater than 20 mg / L PtCo.

10. The method according to any one of claims 1 to 9, wherein the method comprises: After contacting the biomass-based composition with the solid acid catalyst and with the aldehyde removal resin, subject the biomass-based composition to at least one distillation step, and / or subject the biomass-based composition to at least one melt crystallization step.

11. The method according to any one of claims 1 to 10, wherein the method comprises: Before contacting the biomass-based composition with the solid acid catalyst and with the aldehyde removal resin, subject the biomass-based composition to at least one distillation step.

12. The method according to any one of claims 1 to 11, wherein based on the weight of the purified biomass-based composition, the content of ethylene glycol in the purified biomass-based composition is not less than 98 wt.%, for example not less than 99 wt.%, for example not less than 99.25 wt.%, for example not less than 99.5 wt.%, for example not less than 99.75 wt.%, for example not less than 99.9 wt.%.

13. The method according to any one of claims 1 to 12, wherein the biomass-based composition is obtained by pyrolytic cracking of sugars and subsequent hydrogenation.

14. A purified biomass-based composition obtained by the method according to any one of claims 1 to 13, characterized in that, as determined by ASTM D1209-05, its APHA color after heating is less than 20 mg / L PtCo; and as determined by ASTM method E2193-16, its UV transmittance at 275 nm is less than 40%.

15. Use of a purified biomass-based composition obtained by the method for purifying a biomass-based composition according to any one of claims 1 to 13 in the production of a polyester, characterized in that, as determined by ASTM D6290-19, the polyester has one or more of the following CIELAB color space values: L* is not less than 65; a* is from -4 to 4; and b* is from -4 to 4.

16. A method for producing a polyester, the method comprising contacting a purified biomass-based composition obtained by the method for purifying a biomass-based composition according to any one of claims 1 to 13 with at least one reagent to form a polyester, characterized in that, as determined by ASTM D6290-19, the polyester has one or more of the following CIELAB color space values: L* is not less than 65; a* is from -4 to 4; and b* is from -4 to 4.

17. A polyester obtained by the method for producing a polyester according to claim 15, characterized in that, as determined by ASTM D6290-19, the polyester has one or more of the following CIELAB color space values: L* is not less than 65; a* is from -4 to 4; and b* is from -4 to 4.

18. A packaging article or preform made of the polyester according to claim 17.

19. The method, use, polyester, packaging article or preform according to any one of claims 15 to 18, wherein the polyester comprises polyethylene terephthalate.

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