EP4359376A1 - Procédé de production de 1,2-alcanediols et compositions contenant des 1,2-alcanediols - Google Patents

Procédé de production de 1,2-alcanediols et compositions contenant des 1,2-alcanediols

Info

Publication number
EP4359376A1
EP4359376A1 EP22735852.0A EP22735852A EP4359376A1 EP 4359376 A1 EP4359376 A1 EP 4359376A1 EP 22735852 A EP22735852 A EP 22735852A EP 4359376 A1 EP4359376 A1 EP 4359376A1
Authority
EP
European Patent Office
Prior art keywords
alpha
component
ester
carboxylic acid
keto
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22735852.0A
Other languages
German (de)
English (en)
Inventor
Markus Nahrwold
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Minasolve SAS
Original Assignee
Minasolve SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minasolve SAS filed Critical Minasolve SAS
Publication of EP4359376A1 publication Critical patent/EP4359376A1/fr
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/132—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group
    • C07C29/136—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH
    • C07C29/147—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of carboxylic acids or derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C67/00—Preparation of carboxylic acid esters
    • C07C67/30—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group
    • C07C67/317—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by splitting-off hydrogen or functional groups; by hydrogenolysis of functional groups
    • C07C67/32—Decarboxylation

Definitions

  • the invention relates to a process for the preparation of 1,2-alkanediols with carbon chains between 4 and 30 atoms and intermediates thereof.
  • the process provides alpha-keto carboxylic acids and/or esters thereof in a first step and converts them into 1,2-alkanediols in a second step.
  • 1,2-Alkanediols are commonly used as solvents, humectants, conditioners, rheology modifiers and antimicrobial components. They are applied as additives in compositions utilized in various industries, including personal care, cleaning, and medical applications.
  • the most commonly used 1,2-alkanediols contain a straight chain of 3 to 12 carbon atoms.
  • Well-known examples include 1,2-propanediol (propylene glycol), 1,2-butanediol, 1,2-pentanediol (pentylene glycol), 1,2- hexanediol, 1,2-heptanediol, 1,2-octanediol (caprylyl glycol), 1,2-decanediol (decylene glycol) and 1,2-dodecanediol (lauryl glycol).
  • Longer chain 1,2-alkanediols comprise, for example, 1,2-tetradecanediol (myristyl glycol), 1,2-octacosanediol (octacosanyl glycol) and mixtures such as C14-C18 glycol, C18-C30 glycol and C20- C30 glycol.
  • the most common synthetic route for producing such 1,2-alkanediols involves the oxidation of 1-alkenes with hydrogen peroxide as a reagent in combination with a carboxylic acid such as formic acid or acetic acid (see for example D1 : US7385092 B2).
  • the resulting 1,2-epoxyalkanes are reacted with water to give the 1,2-alkanediols, together with the corresponding formate or acetate esters.
  • the obtained mixture of products is further contacted with a suitable base, such as aqueous sodium hydroxide, to convert the alkanediol esters to the free 1,2-alkanediol.
  • a suitable base such as aqueous sodium hydroxide
  • Such “renewable,” “natural,” or “bio” feedstocks therefore contain only modern carbon recently assimilated by a living organism or fixated from the surrounding atmosphere by a green chemical process. They stay in contrast to petrochemical or other fossil feedstock containing "old” carbon.
  • the term "sustainable” refers to materials that come from such renewable sources and are not derived from petrochemical or other fossil sources of carbon.
  • the traditional method for testing the concentration of modern carbon in a product is the determination of the content of carbon-14, a radioactive isotope of carbon that is not present in fossil carbon.
  • Alternatives to radiocarbon analyses are quantification of carbon-14 by accelerated mass spectrometry (AMS), as well as detailed analyses of stable isotopes or stable nuclides using mass spectroscopy, thereby evaluating the ratios of, for example, carbon-12/carbon-13 and/or hydrogen-l/hydrogen-2.
  • biobased 1,2-alkanediols One possible route for the production of biobased 1,2-alkanediols is the replacement of fossil carbon-based 1-alkenes by those obtained from renewable feedstocks (D2 : US10882803 B2).
  • One commonly known route for obtaining bio-based 1-alkenes is the dehydration of biobased primary alcohols (D3 : US8912373 B2).
  • the resulting bio-based 1-alkenes can be used as substitutes for petrochemical 1-alkenes.
  • the dehydration of primary alcohols has several disadvantages: First, it requires heating to temperatures beyond 200 °C, which is quite energy intensive.
  • bio-based fatty alcohols such as 1-hexanol, 1-octanol, 1-decanol or 1- dodecanol are typically obtained from palm kernel oil or coconut oil. These vegetable oils are in high demand, and their production often leads to deforestation and destruction of ecosystems such as tropical rainforest.
  • the dehydration of primary fatty alcohols is not completely selective for the primary 1-alkene. Instead, mixtures of different isomeric alkenes (1-alkene, 2-alkene, 3-alkene, ...) are formed. The reason for this is the rearrangement and migration of the double bond along the carbon chain during the dehydration process of the primary alcohols.
  • the present invention and embodiments thereof serve to provide a solution to one or more of above-mentioned disadvantages.
  • the invention relates to a process according to claim 1.
  • a novel process for obtaining 1,2-alkanediols having carbon chains of about 4 to about 30 atoms involves the reaction of oxalic acid esters (component A) with aldehydes and/or esters of carboxylic acids (component B) to alpha-keto carboxylic acids and/or esters thereof.
  • the reaction takes place in the presence of a base (component C).
  • Subsequent reduction, preferably by catalytic hydrogenation leads to the formation of 1,2-alkanediols. This process is shown in a simplified form in Fig. 1.
  • the disclosed process also avoids the use of concentrated solutions of hydrogen peroxide or peroxyacid, the handling of which can pose a risk of explosion or other exothermic runaway reactions that are difficult or energy- intensive to control.
  • the final step of the disclosed novel process involves a chemical reduction, which reduces the concentration of unwanted oxo-impurities that can impact the quality and safety of the 1,2-alkanediols.
  • the favourable impurity profile of the 1,2-alkanediols obtained from this process enables their application in areas where high purity and low odour are crucial, for example in cosmetics and personal care products.
  • the feedstock used for the disclosed novel production process is preferably bio-based and renewable, which enables sustainable production and avoids non-renewable petrochemicals.
  • the feedstock for the disclosed process is preferably derived from resources other than palm and coconut oil, thereby addressing the need for sustainable alternatives.
  • Antim icrobial systems containing one or more 1,2-alkanediols obtained by the disclosed process.
  • Figure 1 shows a schematic representation of a reaction scheme according to an embodiment of the present invention.
  • Figure 2 shows a schematic representation of a reaction scheme including possible reaction intermediates according to an embodiment of the present invention.
  • Figure 3 shows a schematic representation of a reaction scheme according to an embodiment of the present invention.
  • Figure 4 shows a schematic representation of a reaction scheme including possible reaction intermediates according to an embodiment of the present invention.
  • Figure 5 shows a schematic representation of organometallic catalysts according to an embodiment of the present invention. DETAI LED DESCRI PTI ON OF THE I NVENTI ON
  • a compartment refers to one or more than one compartment.
  • % by weight refers to the relative weight of the respective component based on the overall weight of the formulation.
  • the terms "one or more” or “at least one”, such as one or more or at least one member(s) of a group of members, is clear per se, by means of further exemplification, the term encompasses inter alia a reference to any one of said members, or to any two or more of said members, such as, e.g., any >3, >4, >5, >6 or >7 etc. of said members, and up to all said members.
  • the terms "in a single reaction step”, “in a single reaction” or “in a single synthesis step” refer to one or several reactions which take place in a single reactor. Preferably the reaction occurs simultaneously and does not require a substantial change in reaction conditions. If the reaction is carried out in a continuous manner, preferably the feed rate of reactants is substantially constant. If the reaction is carried out in a batch operation, preferably the feed rate is such that if several reactions occur, they can occur simultaneously rather than subsequently.
  • the invention relates to a process for the production of 1,2- alkanediols comprising the following steps:
  • component B Providing an ester or an aldehyde (component B), which is characterised by having at least one hydrogen atom bound to the second (alpha-)carbon atom.
  • a dialkyl oxalate is provided.
  • the alkyl groups of the dialkyl oxalate are independently selected from lower alkyl groups having from 1 to 8 carbon atoms. More preferably the alkyl groups of the dialkyl oxalate are independently selected from lower alkyl groups having from 1 to 6 carbon atoms, even more preferably the alkyl groups of the dialkyl oxalate are independently selected from lower alkyl groups having from 1 to 4 carbon atoms.
  • the two alkyl groups may be straight or branched. The two alkyl groups may be identical or different.
  • the dialkyl oxalate is selected from diethyl oxalate, dimethyl oxalate, di-n-propyl oxalate, di-n-butyl oxalate, methyl ethyl oxalate, methyl n- propyl oxalate, methyl n-butyl oxalate or a mixture thereof.
  • diethyl oxalate or di-n-butyl oxalate is provided.
  • the dialkyl oxalate can be either used as isolated substance, or it can be generated in situ as part of the production process, by an esterification reaction of oxalic acid with the corresponding alcohol.
  • the esterification is typically mediated by an acidic or alkaline catalyst.
  • the catalyst may be either heterogeneous or homogeneous, i.e., the catalyst may be either soluble in the reaction mixture or a portion thereof, or it may be an insoluble liquid or solid.
  • the esterification reaction may take place in the presence or absence of a solvent, at temperatures ranging from 0 to 250 °C and at pressures ranging from 0.01 mbar to 100 bar.
  • the reaction takes place at the boiling point of the solvent or alcohol used and/or at the boiling point of azeotropic mixtures formed in the reaction mixture.
  • esterification of oxalic acid with ethanol offers the advantage of abundant availability of this alcohol from bio-based and sustainable sources.
  • the low molecular weight of ethanol provides a high yield per volume, which is advantageous in terms of productivity.
  • diethyl oxalate is liquid at ambient temperature, which simplifies handling on an industrial scale.
  • esterification of oxalic acid with n-butanol offers the advantage of easy removal of the water formed during esterification by azeotropic distillation. Since n-butanol forms a heterogeneous azeotrope with water, no additional solvent is required for the reaction. This simplifies recycling, which is why processes based on n-butanol can be regarded as particularly economical and environmentally friendly.
  • dibutyl oxalate is liquid at room temperature. The lipophilic nature of butanol and dibutyl oxalate facilitates rapid phase separation during aqueous workup. It also allows esterification under phase transfer conditions, optionally in the absence of an additional solvent.
  • the water contained in the oxalic acid and/or formed during the esterification reaction is preferably removed from the ester. It may be removed, for example, by azeotropic distillation, whereby either a heterogeneous or a homogeneous low-boiling mixture ("azeotropic mixture” or “azeotrope") of water and organic component is removed from the reaction mixture. The removal can be realized, for example, by distillation.
  • the solvent is returned to the reaction mixture after the water has been removed, using suitable technologies such as phase separation or adsorption or combinations thereof.
  • the reaction mixture or distilled solvent is contacted with an absorbent capable of absorbing the water contained in the solvent or reaction mixture.
  • the esterification takes place under phase transfer conditions in the presence of an organic solvent.
  • the solvent should be capable of at least partially dissolving the dialkyl oxalate formed, while exhibiting limited miscibility with water.
  • the ester formed is taken up by the solvent and is therefore protected from a hydrolysis reaction with the water present in the reaction mixture.
  • the use of phase transfer reaction conditions and the removal of water by azeotropic distillation or adsorption can also be combined.
  • the alcohol used as reaction partner also serves as the organic solvent.
  • dialkyl oxalate is synthesized via a transesterification reaction.
  • the oxalic acid used as starting material is preferably produced by oxidation of carbohydrates such as sugar or cellulose with nitric acid.
  • the nitrogen oxides produced as a by-product are preferably recycled, making the production process sustainable and environmentally friendly.
  • a carboxylic acid ester and/or an aldehyde characterised by having at least one hydrogen atom bound to the second (alpha-) carbon atom.
  • the ester or aldehyde is preferably of bio-based origin.
  • An exemplary list of commercially available biobased feedstocks is provided below, without this listing being construed as a limitation:
  • Propanoic acid (propionic acid), butanoic acid (butyric acid), pentanoic acid (valeric acid) and hexanoic acid (caproic acid) are obtained by fermentation of sugar (AFYREN process).
  • Heptanal and undecanoic acid are obtained from the ricinoleic acid esters contained in castor oil, following a thermal treatment (ARKEMA process).
  • Heptanoic acid enanthic acid
  • heptanal is accessible by oxidation of heptanal.
  • Nonanoic acid (pelargonic acid) can be obtained by oxidative cleavage of oleic acid derived from vegetable oil.
  • Hexanoic acid (caproic acid), octanoic acid (caprylic acid), decanoic acid (capric acid), dodecanoic acid (lauric acid), myristic acid (C14), myristoleic acid (C14: l), palmitic acid (C16), stearic acid (C18), oleic acid (C18: l), palmitoleic acid (C18: l), linoleic acid (C18:2), linolenic acid (C18:3), arachidic acid (C20), arachidonic acid (C20:4), behenic acid (C22), erucic acid (C22: l), lignoceric acid (C24), cerotic acid (C26), montanic acid (C28) and melissic acid (C30) are examples of carboxylic acids commonly found in vegetable oils and natural waxes.
  • the carboxylic acids are esterified with an alcohol prior to condensation with dialkyl oxalate.
  • the carboxylic acids are reacted with a mono-, di- or trihydric alcohol having from 1 to 8 carbon atoms.
  • the carboxylic acids are converted to their methyl-, ethyl, n-propyl or n-butyl esters by reaction with the corresponding alcohols.
  • the carboxylic acids are converted to their ethyl or butyl esters by reaction with bio-based ethanol or bio-based butanol.
  • the esterification of the carboxylic acid with ethanol offers the advantage of abundant availability of this alcohol from bio-based and sustainable sources.
  • the low molecular weight of ethanol provides a high yield per volume, which is advantageous in terms of productivity.
  • ethyl esters of fatty acids are typically liquid at ambient temperature, which simplifies handling on an industrial scale.
  • n-butanol The esterification of the carboxylic acid with n-butanol offers the advantage of easy removal of the water formed during esterification by azeotropic distillation. Since n- butanol forms a heterogeneous azeotrope with water, no additional solvent is required for the reaction. This simplifies recycling, which is why processes based on n-butanol can be regarded as particularly economical and environmentally friendly.
  • butyl esters of fatty acids are typically liquid at room temperature. The lipophilic nature of butanol and butyl esters facilitates rapid phase separation during aqueous workup. It also allows esterification under phase transfer conditions, optionally in the absence of an additional solvent.
  • the carboxylic acid esters can either be provided separately, or they can be synthesized in one step together with a dialkyl oxalate.
  • the second option offers the advantage that only one esterification step is necessary. Similar reaction conditions can be employed as outlined above for the production of dialkyl oxalates (step 1).
  • At least one dialkyl oxalate (component A) reacts with at least one carboxylic acid ester and/or at least one aldehyde (component B), thereby forming a new carbon-carbon bond between the second carbon (alpha-carbon) of the ester or the first carbon of the aldehyde and one of the carbon atoms of the oxalate.
  • the reaction is mediated by a base (component C) that is characterised by being sufficiently strong to subtract a C-H-acidic proton.
  • the base is an alkali or earth alkali alkoxide of a lower alcohol, such as methanol, ethanol, 1-propanol, 2- propanol, n-butanol, sec-butanol, tert-butanol or other isomers thereof.
  • the alkoxide is selected from sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium methoxide, potassium ethoxide, or potassium tert- butoxide.
  • the alkoxide can be either used in its pure form as a dry solid, or as a solution in the corresponding alcohol.
  • the alkoxide can be formed in situ, for example by addition of a metal, a metal hydride or a metal amide to the alcohol.
  • the reaction can be carried out without additional solvent or in the presence of a suitable solvent.
  • Polar/hydrophilic as well as non-polar/hydrophobic solvents can be used.
  • the at least one alcohol formed during the reaction is removed from the reaction mixture by distillation.
  • the formic acid ester is removed from the reaction mixture by means of a distillation.
  • reaction mixture is cooled below the boiling point of the formic acid ester, in order to avoid evaporation of the potentially flammable and low boiling ester during the reaction.
  • the at least two reactants can be added to the base (component C) either separately or simultaneously.
  • the base can be added to one of the two reactants or to both reactants.
  • the dialkyl oxalate is charged first, followed by addition of the base and finally dosage of the ester or aldehyde.
  • the condensation reaction can be carried out at temperatures of between -80°C and + 150°C, preferably between -20°C and +100 °C, most preferably between 0°C and 50°C.
  • the dosage of either of the three reactants, i.e., the base, the dialkyl oxalate and the ester or aldehyde can be adjusted to keep exothermic reactions under control.
  • the base (component C) and the aldehyde and/or ester (component B) can be used in molar ratios of between 1:10 and 10: 1.
  • the base is used in a molar excess.
  • the base is used in a molar ratio of at least 1.3: 1, more preferably at least 1.5: 1, more preferably at least 1.6: 1, more preferably at least 1.7: 1, more preferably at least 1.8: 1, more preferably at least 1.9: 1, more preferably at least 2: 1, with respect to the aldehyde or ester.
  • the base is used in a molar ratio of at least 1.5: 1, more preferably at least 1.6: 1, more preferably at least 1.7: 1, more preferably at least 1.8: 1, more preferably at least 1.9: 1, more preferably at least 2: 1, with respect to the sum of aldehyde and ester. More preferably, the base is used in a molar ratio of at most 10: 1, more preferably at most 8: 1, more preferably at most 7: 1, more preferably at most 6:1, more preferably at most 5: 1, more preferably at most 4: 1, more preferably at most 3: 1, more preferably at most 2.5: 1, with respect to the aldehyde or ester, more preferably with respect to the sum of aldehyde and ester.
  • the base is used in a molar ratio of about 2: 1 or more with respect to the aldehyde or ester, more preferably with respect to the sum of aldehyde and ester.
  • the inventors found a molar excess of 2: 1 of base to aldehyde and / or ester is desirable to maximize the conversion. Increasing the molar excess past 2: 1 of the sum of aldehyde and ester has limited effects on conversion as complete or near complete conversion is already obtained.
  • the dialkyl oxalate can be used in a molar ratio of between 1: 100 - 100: 1 with regard to the ester or aldehyde.
  • the dialkyl oxalate is used in a molar excess compared to the ester or aldehyde.
  • the dialkyl oxalate is used in a 1.1-fold to 10-fold molar excess compared to the ester or the aldehyde.
  • the intermediates A and/or B are either isolated, or they are directly converted to the corresponding alpha-keto acids and/or alpha-keto ester in the following step 4.
  • the intermediates A and/or B are not isolated, but are transferred to the corresponding alpha-keto ester without prior extensive purification.
  • excess amounts of dialkyl oxalate(s) are removed from the product mixture. These can be reused in the production of a subsequent batch, thus reducing the costs and the amount of resources required.
  • a preferred method for removing the excess dialkyl oxalate(s) is vacuum distillation.
  • the intermediates A and/or B are converted to the corresponding alpha-keto carboxylic acids and/or alpha-keto esters by reaction under acidic or under alkaline conditions.
  • Alpha-ketoacids are described in prior art as being somehow instable with a tendency to condense with themselves under strong acidic or basic conditions, following the aldol-like pathway.
  • the formation of alpha-ketoacids usually involves the treatment of a precursor with strong alkali or strong acid. It can therefore be concluded that alpha-ketoacids are sufficiently stable under such conditions, providing the reaction conditions such as reaction time and temperature are kept under control.
  • Alpha-oxaloesters (intermediate A) are preferably converted to alpha-keto carboxylic acids under acidic conditions. In the course of the conversion, ester bonds get hydrolysed and carbon dioxide is released as a leaving group of a decarboxylation reaction.
  • the applied acids can be any Bronsted or Lewis acids that are sufficiently strong to mediate the desired reaction.
  • the acids can be either soluble in at least one compartment of the reaction mixture (homogenous), or they can be insoluble solids (heterogenous).
  • Suitable acids comprise, for example, mineral acids such as hydrochloric acid, sulphuric acid, or phosphoric acid, as well as heteropoly acids such as molybdic, tungstic, or silicic acid.
  • Other suitable acids comprise soluble organic acids such as para-toluene sulphonic acid, methane sulphonic acid or trifluoro methane sulphonic acid.
  • Insoluble or heterogenous acids may comprise, for example, polyacryl or polystyrene or fluorinated resins that are available under trade names such as Amberlite®, Amberlyst®, DOWEX®, Purolite® or National®. Heterogenous acids may further comprise acidic minerals such as, for example, Zeolite or other silicates or aluminosilicates. The acid is preferably used in a molar excess with respect to the intermediate A.
  • the alpha-oxalo ester (intermediate A) is reacted only with hot water at temperatures of at least 150°C, preferably between 150°C and 250°C.
  • the hot water is used as reagent and solvent which is able to generate sufficiently acidic conditions for the thermal decarboxylation of the intermediates, particularly the alpha-oxalo ester (intermediate A).
  • This variant typically leads to the direct formation of alpha-keto esters as the major product. It therefore avoids the isolation of the free alpha-keto carboxylic acid and its further conversion to the alpha-keto ester.
  • the pH of the intermediate and hot water mixture lies between 3 and 10, preferably between 4 and 9, more preferably between 5 and 8, more preferably between 6 and 8, most preferably about 7.
  • the low acidity of hot water also typically avoids side-reactions of the Aldol type.
  • the alpha-oxalo ester (intermediate A) is preferably purified by aqueous extraction in order to remove basic and/or alkaline impurities.
  • the alpha-oxaloester (intermediate A) is first hydrolysed under alkaline conditions.
  • Any base capable of generating a sufficiently high pH can be used for this purpose.
  • the at least one base can either be soluble in at least one compartment of the reaction mixture (homogeneous), or it can be an insoluble solid (heterogeneous).
  • Suitable bases include alkali metal hydroxides or alkaline earth metal hydroxides.
  • Insoluble or heterogeneous bases can consist, for example, of polyacrylic or polystyrene resins available under trade names such as Amberlite®, Amberlyst®, DOWEX® or Purolite®.
  • the resulting carboxylate salt is then neutralized with an acid and subjected to a decarboxylation reaction under acidic conditions as described above.
  • the alcohol released during the alkaline hydrolysis is preferably removed from the reaction mixture to avoid conversion of the alcohol to an alkene by elimination of water under strongly acidic conditions. The removal may be carried out, for example, by distillation or extraction or phase separation. In a further embodiment, the removed alcohol is recycled or reused. In a preferred embodiment, the isolated alcohol is reacted with the alpha-keto acid obtained in step 4.
  • the cyclic intermediate B is preferably converted to the corresponding alpha-keto carboxylic acid under alkaline conditions.
  • Any base can be used that is able to create a sufficiently high pH-value.
  • the at least one base can be either soluble in at least one compartment of the reaction mixture (homogenous), or it can be an insoluble solid (heterogenous).
  • Suitable bases comprise, for example, alkali or earth alkali hydroxides.
  • Insoluble or heterogenous bases may comprise, for example, polyacrylic or polystyrene resins that are available under trade names such as Amberlite®, Amberlyst®, DOWEX® or Purolite®.
  • the conversion of intermediate A and/or intermediate B to an alpha-keto carboxylic acid may take place in the presence or absence of a solvent and/or a phase transfer catalyst, at temperatures ranging from 0 to 250 °C and at pressures ranging from 0.01 mbar to 100 bar.
  • the reaction takes place at temperatures of not more than 150°C, most preferably not more than 100°C.
  • the obtained alpha-keto carboxylic acid is either directly subjected to a reduction reaction (step 6), or it is optionally converted to an ester (step 5) before being subjected to a reduction reaction.
  • the obtained alpha-keto carboxylic acid is esterified by reaction with an alcohol.
  • the ester is formed by reaction with a lower alcohol containing between 1 and 8 carbon atoms.
  • methyl or ethyl or n-propyl or n-butyl esters are formed.
  • the esterification of the alpha-keto carboxylic acid with ethanol offers the advantage of abundant availability of this alcohol from bio-based and sustainable sources.
  • the low molecular weight of ethanol provides a high yield per volume, which is advantageous in terms of productivity.
  • ethyl esters of alpha-keto carboxylic acids are typically liquid at ambient temperature, which simplifies handling on an industrial scale.
  • esterification of alpha-keto carboxylic acids with n-butanol offers the advantage of easy removal of the water formed during esterification by azeotropic distillation. Since n-butanol forms a heterogeneous azeotrope with water, no additional solvent is needed for the reaction. This simplifies recycling, which is why processes based on n-butanol can be regarded as particularly economical and environmentally friendly.
  • butyl esters of alpha-keto carboxylic acids are typically liquid at room temperature. The lipophilic nature of butanol and butyl esters facilitates rapid phase separation during aqueous workup. It also allows esterification under phase transfer conditions, optionally in the absence of an additional solvent.
  • the esterification reaction (step 5) is combined with the formation of the alpha-keto carboxylic acid (step 4).
  • Suitable reaction conditions comprise, for example, the use a lipophilic solvent or co-solvent that is characterised by having a low or limited solubility in water.
  • lipophilic solvents allow the formation of esters of alpha-keto carboxylic acids under phase-transfer condition, where the ester is taken up by the solvent. This limits the contact of the ester with water and thereby protects the ester bond from hydrolysis.
  • Suitable solvents are, for example, selected from alkanes such as hexane, heptane or cyclohexane, ethers such as tert-butyl methyl ether (MTBE), 2-methyltetrahydrofuran or dialkyl ethers, and aromatic solvents such as toluene or xylene.
  • a lipophilic alcohol such as 1-butanol, is used as solvent and reactant.
  • esterification can be catalysed by a suitable enzyme.
  • suitable enzymes include esterases such as Candida antarctica lipase B (CALB).
  • the enzyme can be used in its free form, or it can be immobilised on a solid support.
  • the formed ester is either isolated by common techniques or used in the following step 6 without further purification.
  • the alpha-keto carboxylic acid and/or alpha-keto carboxylic acid ester is converted to a 1,2-alkanediol by reducing the keto-function to a secondary alcohol and the carboxylic acid and/or ester to a primary alcohol.
  • the reduction can be carried out either in one step, or in several consecutive steps.
  • the carbonyl group of the keto-function can be first reduced to form a secondary alcohol, and the remaining carboxylic acid or ester function can be reduced in second step to a primary alcohol.
  • the alpha-hydroxy acid or alpha- hydroxyester can be isolated and/or purified before further conversion to the 1,2- alkanediol.
  • the alpha-hydroxy carboxylic acid and/or alpha-hydroxy carboxylic acid ester is not isolated prior to reduction to the 1,2-alkanediol.
  • the carbonyl group of the alpha-keto carboxylic acid and/or alpha-keto carboxylic acid ester is first reduced to a secondary alcohol. Two molecules of the resulting alpha-hydroxy acid or alpha-hydroxyester are then reacted by forming a cyclic dimeric ester of the lactide type. This cyclic dimeric ester is further reduced, thereby yielding two molecules of 1,2-alkanediol.
  • the cyclic ester can be isolated and optionally purified before conversion to the 1,2-alkanediol.
  • the cyclic ester is formed in situ and directly converted to the 1,2-alkanediol without prior isolation or purification.
  • the reductions during step 6 are carried out by means of a catalytic hydrogenation in the presence of a suitable metal catalyst.
  • Hydrogenation of the alpha-carbonyl function to a secondary alcohol function is generally not challenging for reduction by catalytic hydrogenation. Further hydrogenolysis of the carboxyl group to a primary alcohol requires significantly harsher conditions, such as higher temperature and/or higher pressure of hydrogen gas.
  • More than one type of catalyst can be used in case of a stepwise reduction. In a preferred embodiment, all reduction reactions are catalysed by the same catalyst.
  • Examples for suitable catalysts for the hydrogenation of alpha-keto carboxylic acids and/or of alpha-keto carboxylic acid esters to 1,2-alkanediols comprise heterogenous and/or homogenous metal catalyst.
  • Suitable heterogenous hydrogenation catalysts contain one or more of the following metals: Copper, Chromium, Cobalt, Cerium, Nickel, Iron, Ruthenium, Palladium, Platinum, Rhodium, Tantalum, Niobium, Iridium, Osmium, Rhenium, Gold, Silver, Manganese, Tin, Boron, Indium, Vanadium, Molybdenum and Tungsten.
  • the metals are provided in their metallic form and/or in another catalytically active oxidation state, for example as (potentially reducible) metal oxides.
  • the heterogenous metal catalyst is provided on a solid support and/or in combination with a binder.
  • Examples comprise carbon, aluminium oxide (alumina), silicium dioxide (silica, also fumed), silicic acid, silicium carbide, zinc oxide, zirconium oxide, barium oxide, magnesium oxide, titanium dioxide, cerium oxide, zirconium oxide, hydroxyapatite, aluminosilicates such as Mordenite and Zeolite, magnetic nanoparticles, polymers, or combinations thereof.
  • the catalyst can also be of the RANEY® type, where one compartment (usually aluminium) is removed from an alloy of metals by treatment with a base (for example an aqueous solution of alkali hydroxide), thereby providing a sponge like metal catalyst.
  • Preferred heterogeneous catalysts for the hydrogenation of alpha-keto acids comprise noble metal catalysts based on Ruthenium, Platinum, Rhenium, Palladium, Rhodium and/or Iridium, and non-noble metal catalysts based on Copper, Nickel, Cobalt and/or Molybdenum.
  • the catalysts are preferably designed to minimize leaching of metal into the reaction medium.
  • Combinations of different metals, as well as metal/metal oxide combinations and/or the use of suitable supports and/or promoters can be employed to improve reactivity and selectivity with respect to the desired diol.
  • Preferred heterogeneous catalysts for the hydrogenation of alpha-keto esters comprise noble metals, optionally in combination with promoters, most preferably bimetallic catalysts such as Pd/Re and Pt/Re.
  • catalysts combining at least one hydrogenation metal (e.g. Ru, Pt, Pd, Rh) and at least one promoter metal (e.g. tin, rhenium, molydenum) and exhibiting a synergistic effect are preferred.
  • Copper, silver and gold can also act as promoters to platinum group metals.
  • the catalyst support and the optional solvent system may further promote the catalytic transformation. Support materials such as for example Ti02 and/or ZnO may assist in carbonyl group and/or dihydrogen activation.
  • heterogeneous catalysts for the hydrogenation of alpha-keto esters are non-noble metal catalysts.
  • suitable catalysts comprise:
  • Copper chromite and zinc chromite catalysts (Adkins type), as well as Cu-Fe spinel and Cu-Fe-AI mixed oxide systems substituting the Cr component for Fe.
  • Supported copper catalysts such as Cu/ZrC>2, Cu/SiC>2, Cu/SiC>2/ZnO, or Cu/SiC>2 hybrid catalysts containing the zeolite H-ZSM-5.
  • the heterogenous catalyst(s) can be activated prior to application in the synthesis of 1,2-alkanediols, for example by heating in the presence or absence of hydrogen and/or water steam and/or an inert carrier gas.
  • the heterogenous catalyst is reused several times in consecutive batches and/or used for a longer time in a continuous hydrogenation reaction.
  • heterogenous catalysts for the hydrogenation of alpha-keto esters to 1,2-alkanediols are Ruthenium catalysts.
  • homogeneous hydrogenation catalysts are employed which are soluble in at least one compartment of the reaction medium. They typically are organometallic complexes consisting of at least one metal-center which is coordinated to one or more ligands. These ligands may have oxygen, nitrogen, phosphorus, or sulphur at the binding site which bind to the metal through a lone pair of electrons. They may also contain a carbon group that binds to the metal via a s-bond or via n-interactions, such as benzene, diene, or allyl-groups. Carbenes are another type of viable ligands, having an electron sextet at a carbon atom.
  • homogenous catalysts for hydrogenation of esters are selected from organometallic pincer-type complexes, such as those described in a review by Nielsen et al. (Catalysts 2020, 10, 773).
  • Pincer ligands bind to a metal with two donor atoms (for example phosphorus, nitrogen, or sulphur) and one s-bond.
  • Phosphines (P), nitrogen (N) or sulphur (S) are often used as donors.
  • PNP nitrogen-metal s- bonds
  • NCN nitrogen-carbon nitrogen
  • SCS sulphur-carbon sulphur
  • Phenyl systems usually serve as the ligand backbone, but aliphatic systems are also known. If the ligands are bonded to a metal, the resulting coplanar structure is very rigid. This leads to an increased thermal stability of the homogenous catalyst.
  • Ru-MACHO Ligands containing phosphine and amine moieties, such as Ru-MACHO developed at Takasago, are known as effective catalysts for the conversion of esters to alcohols (WO2011048727A). Suitable organometallic complexes are shown in Fig. 5.
  • Ru- MACHO (C1 ) and similar catalysts require the addition of a base, typically an alkali or earth alkali alcoholate such as sodium methoxide, sodium ethoxide, sodium tert- butoxide, potassium methoxide, potassium ethoxide, or potassium tert-butoxide.
  • a base typically an alkali or earth alkali alcoholate such as sodium methoxide, sodium ethoxide, sodium tert- butoxide, potassium methoxide, potassium ethoxide, or potassium tert-butoxide.
  • Replacing the chloride in Ru-MACHO by hydride-BH3 affords Ru-MACHO-BH (C2) that is also
  • Pincer Ruthenium complex C3 bearing a monodentate N-heterocyclic carbene ligand demonstrated high efficacy under low pressure of hydrogen gas ( Organic Letters 2016, 18/15, 3894-3897).
  • Pincer-type catalysts developed by MILSTEIN et al. are another type of suitable catalysts. Examples comprise PNN-complexes such as C4 and C5, and PNP- complexes like C6 (WO2012052996 A2; Angew. Chem. Int. Ed. 2006, 45, 1113- 1115).
  • Particularly preferred homogenous catalysts for the hydrogenation of alpha-keto esters to 1,2-alkanediols are the Ruthenium-complexes C7 and C8.
  • the source of hydrogen for the hydrogenation of carboxylic acid and/or esters and ketones is selected from either hydrogen gas or from organic substances that act as hydrogen donors.
  • the hydrogen gas can be produced, for example, by steam reforming of hydrocarbons or by electrolysis of water. Another option is the generation of hydrogen in situ by catalytic transfer of hydrogen from a donor molecule.
  • Suitable hydrogen donors for transfer hydrogenation include formate, as well as alcohols such as 2-propanol, but any other suitable molecule can also be used as a donor.
  • the hydrogenation reactions can be either carried out in a liquid phase or in a gaseous phase.
  • the conversions can be carried out batch-wise, for example in a stirred vessel. They can also be carried out in equipment suitable for continuous hydrogenation, for example by introducing the reactants to a trickle-bed or fixed bed tube-reactor or a loop reactor (such as BUSS loop or similar), or a fluidised bed reactor.
  • the hydrogenation can be carried out in the presence or absence of a suitable solvent that may act as transporter, mediator, and diluent.
  • suitable solvent that may act as transporter, mediator, and diluent.
  • protic solvents are water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, or mixtures thereof.
  • aprotic solvents are ethers such as methyl-tert-butyl ether or 2- methyltetrahydrofuran, as well as hydrocarbons such as cyclohexane, heptane, octane or decalin.
  • the hydrogenation reaction is preferably carried out at a temperature of between -20°C and 300°C, more preferably between 0°C and 250°C.
  • the hydrogenation of alpha-keto carboxylic acids, alpha-keto esters or a mixture thereof is preferably carried out under hydrogen partial pressure of between 1 bar and 300 bar hydrogen, preferably between 5 bar and 100 bar hydrogen, more preferably 5 to 50 bar hydrogen. In a further preferred embodiment, the hydrogenation is carried out under a total pressure of between 1 bar and 300 bar, preferably between 5 bar and 100 bar, more preferably 5 to 50 bar.
  • the hydrogen partial pressure is at least 75% of the total pressure, more preferably at least 80% of the total pressure, more preferably at least 85% of the total pressure, more preferably at least 90% of the total pressure, more preferably at least 95% of the total pressure, more preferably at least 97% of the total pressure, more preferably at least 98% of the total pressure, more preferably at least 99% of the total pressure, more preferably at least 99.5% of the total pressure.
  • any of the intermediates formed in the course of the production process, during any of the aforementioned steps 1-6, may undergo a distillation step to refine the substance prior to the subsequent chemical reaction.
  • the 1,2-alkanediol formed in the final stage 6 may also undergo a final distillation step to refine the 1,2-alkanediol.
  • the aim of the purification step 7 is to remove undesired impurities or fractions.
  • the final 1,2-alkanediol is distilled under reduced pressure, most preferably at a pressure not exceeding 20 mbar and/or at temperatures not exceeding 150 °C. Such conditions effectively avoid thermal degradation of the diols and the formation of malodorous decomposition products.
  • the overall process preferably yields at least about 50% to about 99% of the 1,2- alkanediol, and more preferably yields at least about 70% to about 99% of the 1,2- alkanediol.
  • the 1,2-alkanediols obtained by the production process described herein have a carbon chain of between 4 and 30 carbon atoms.
  • the 1,2-alkanediols have a carbon chain of from about 5 to about 14 carbon atoms.
  • the 1,2-alkanediols may have a carbon chain length of from about 5 to about 10 carbon atoms.
  • the 1,2-alkanediol may be, for example, 1,2-pentanediol and/or 1,2- hexanediol and/or 1,2-heptanediol and/or 1,2-octanediol and/or 1,2-decanediol.
  • the obtained 1,2-alkanediols can be straight-chain or branched molecules. Preferably, they are straight-chain molecules.
  • the 1,2-alkanediols may contain one or more functional or substituted groups, such as sulphate or sulfonate groups, hydroxyl groups, ether groups, amine groups, halogenated groups, aryl or arene or other aromatic groups and similar functional groups, without any limitation being intended.
  • said alpha-keto carboxylic acid, said alpha-keto ester or said mixture thereof is reduced by hydrogenation with H2, preferably the hydrogenation comprises a H2 partial pressure between 5 and 100 bar, preferably the hydrogenation is carried out over a catalyst, more preferably a ruthenium catalyst, most preferably ruthenium complexes C7 and / or C8, preferably at a hydrogenation temperature between 0 and 250°C,
  • the preferred features and steps of this embodiment may be present or absent independently from one another. Most preferably, all preferred features are present.
  • the vacuum distillation of preferred step 3.1 allows for an (energy) efficient method to separate the excess reagents (and solvent), without the need to purify the intermediate to a higher degree. This further advantageously allows the excess reagents and solvent to be integrally recycled, reducing the requirement for (virgin) reagents and solvent.
  • the aqueous extraction of step 3.2 allows for quick and efficient removal of basic and / or alkaline impurities.
  • the preferred reaction with hot water as described in step 4) advantageously favours the formation of the alpha- keto ester and limits the production of alpha-keto carboxylic acid as well as undesired side-reactions.
  • the resulting product is sufficiently pure to integrally reduce, preferably hydrogenate, according to step 6. There is thus no need for optional step 5, nor the need for purification of the alpha-keto carboxylic acid or the alpha-keto ester.
  • the 1 ,2-alkanediols obtained via a process according to the first aspect of the invention can be used alone, as combination of different types of 1 ,2-alkanediols, or in m ixtures w ith other natural or conventional antim icrobials and/ or further solvents or additives.
  • the invention in a second aspect, relates to a method of providing antim icrobial activity to a composition, including incorporating an antimicrobial system into the composition, wherein the antimicrobial system comprises at least one 1,2-alkanediol having a carbon chain length of from about 4 to about 21 carbon atoms synthesized by conversion of at least one aldehyde or carboxylic acid ester having a carbon chain of from about 3 to about 20 carbon atoms.
  • the invention relates to the use of 1 ,2-alkanediols obtained by a process according to the first aspect of the invention as antim icrobial ingredients in com positions.
  • Such compositions may include cosmetic, pharmaceutical, dermatological, hygienic, agrochemical or other industrial preparations.
  • compositions include: a) Solutions (aqueous, organic, hydro-alcoholic, hydro-glycolic) b) suspensions, c) emulsions (oil in water, water in oil, silicon in water, water in silicon, microemulsions) d) gels, e) ointments, f) pastes, g) syrups, h) solids and/or powders, i) foams, j) soaps, k) capsules,
  • compositions may be intended for use as, for example, skin care, hair care, oral care, health care, fabric care or cleaning products.
  • compositions may optionally further include at least one solubilizing agent in a ratio of about 1: 10 to 10: 1 by weight of the solubilizing material versus the 1,2- alkanediol(s).
  • Suitable solubilizing agents may include for example alkanediols, as well as derivatives of polyethylene glycol, polypropylene glycol and/or polyglycerol.
  • the 1,2-alkanediols obtained by the process according to the first aspect of the invention can be added to compositions at any time during the production process. The addition preferably takes place towards the end of the formulation process, in order to ensure a high concentration of 1,2-alkanediol in the water phase of the formulation.
  • the 1,2-alkanediols of the invention are preferably incorporated in an amount of about 0.1 to about 10 weight percent, and preferably 0.3 to about 2 weight percent, of the total composition.
  • the invention relates to a cosmetic, pharmaceutical, dermatological or hygienic product containing at least one 1 ,2-alkanediol obtained by the process according to the first aspect of the invention, wherein the product passes a microbial challenge test according to the norm ISO 11930.
  • the invention relates to antim icrobial systems containing one or more 1,2-alkanediols obtained by a process according to the first aspect of the invention.
  • the antimicrobial systems may further contain at least one additional component with antimicrobial activity, such as, but not limited to:
  • Alkanediols that were made by another process than the one according to the first aspect of the invention. These diols can be either derived from bio-based or petrochemical feedstock.
  • suitable alkanediols comprise 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3- butanediol, 2,3-butanediol, 3-methyl-l,3-butanediol (isopentyl diol), 1,2- pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol (hexylene glycol), 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, 1,2- decanediol, and 1,2-dodecanediol.
  • Aromatic alcohols and/or phenylpropanoids such as benzyl alcohol, 2- phenylethanol, 2-phenylethanal, 3-phenylpropan-l-ol, cinnamaldehyde, cinnamyl alcohol, 3-phenylpropanal.
  • Glyceryl mono and/or di-esters and/or glyceryl mono-ethers such as, but not limited to, glyceryl caprylate, glyceryl caprate, glyceryl caprylate/ca prate, glyceryl laurate, 2-ethylhexyl glyceryl ether
  • Lower aliphatic alcohols such as ethanol, 1-propanol, 2-propanol.
  • Carboxylic acids such as levulinic acid, benzoic acid, sorbic acid, cinnamic acid, p-anisic acid, salicylic acid, as well as the corresponding alkali or earth alkali salts and/or corresponding esters with lower alcohols or with aromatic alcohols.
  • Essential oils obtained by extraction or steam distillation of vegetable material, such as but not limited to cassia oil, cinnamon oil, tea tree oil, citrus peel or flower oils, Peru balm, lemon grass oil.
  • Extracts and botanicals obtained by immersion of natural materials of vegetable and/or marine origin in a solvent or supercritical fluid, optionally followed by removal of the extraction medium by evaporation or sublimation or solvent exchange.
  • Preservatives and/or microbicides such as parabens (methyl, ethyl, propyl, and butyl), Quaternium 15, diazolidinyl urea, imidazolidinyl urea, DMDM hydantoin, 2-bromo-2-nitropropane-l,3-diol (Bronopol), sodium hydroxyglycinate, sodium hydroxymethylglycinate, phenoxyethanol, methylisothiazolinone and/or methylchloroisothiazoline, benzylisothiazolinone, dehydroacetic acid, sodium dehydroacetate, formaldehyde and/or formaldehyde releasing agents, MDM hydantoin, iodopropynyl butylcarbamate chloroxylenol, methyldibromo glutaronitrile, chlorphenesin, triclosan, triclocarban, benzalkonium chloride
  • the 1,2-alkanediols are preferably present in the antimicrobial systems in a ratio of the l,2-alkanediol(s) to any other antimicrobial component(s) of from about 99:1 to about 1:99, and preferably from about 75:25 to about 25:75 in the antimicrobial system.
  • antimicrobial systems may be characterized by having a synergistic antimicrobial effect that exceeds the additive antimicrobial effects of their individual components by at least 5%, preferably at least about 10%, and more preferably at least about 20%.
  • Such so-called "boosting" effects and antimicrobial effects in a formulation are evaluated using microbiological testing protocols known as "challenge tests.”
  • Preservatives and antimicrobials used in cosmetic, toiletry and pharmaceutical formulations must enable the products to successfully pass such tests.
  • Challenge tests are conducted by adding known amounts of microorganisms to a product and measuring the increase or decrease in the microorganism population over time.
  • the microorganisms added include Gram-positive bacteria, Gram-negative bacteria, yeast(s) and mold(s).
  • a widely accepted standard for challenge testing is defined by ISO 11930.
  • Other suitable test protocols and acceptance criteria are described in the European Pharmacopoeia (Efficacy of Antimicrobial Preservation) and the Japanese Pharmacopoeia (Preservation Effectiveness Tests).
  • Other appropriate challenge test protocols may be used.
  • Also disclosed herein are methods of using 1 ,2-alkanediols for the creation of self-preserving com positions. Each of such methods includes incorporating into the composition at least one 1,2-alkanediol, combination(s) of at least two different 1,2-alkanediols, or combination(s) of at least one 1,2-alkanediol with at least one other compound different from the at least one 1,2-alkanediol.
  • the l,2-alkanediol(s) either act as an antimicrobial agent or boost the antimicrobial efficacy of the overall composition.
  • such compositions are self- preserved against microbial infestation without the need for adding further preservatives.
  • Personal care and pharmaceutical formulations containing 1,2-alkanediols will also preferably contain water.
  • the formulations may further contain any other functional or active ingredients, such as but not limited to flavours and/or fragrances, fats and/or oils, surfactants, thickeners, emollients, humectants, emulsifiers, chelating agents, gelling agents, binders, texturizing agents, solvents, mineral and/or organic UV filters and/or UVA and/or UVB blocking agents, antioxidants, waxes, polymers, inorganic and/or organic pigments, colouring agents, clays and/or other mineral powders, vegetable materials, natural extracts, essential oils, APIs and other additives commonly used in such formulations.
  • any other functional or active ingredients such as but not limited to flavours and/or fragrances, fats and/or oils, surfactants, thickeners, emollients, humectants, emulsifiers, chelating agents, gelling agents
  • each additive is present in an amount up to about 75% by weight of the total formulation, and more preferably up to about 40% by weight, with the total amount of such additives preferably not exceeding about 50% by weight.
  • Household product compositions containing 1,2-alkanediols may include both household cleaners and fabric care compositions.
  • Cleaning compositions may contain detergents that are active ingredients for cleaning, such as quaternary ammonium compounds, bleaching agents, or basic or acidic cleaning agents.
  • Commercially available cleaning agents based on quaternary ammonium compounds include various antibacterial cleaners for disinfection or sanitization.
  • Such compositions may contain other antimicrobial agents and/or other preservatives to maintain adequate shelf life. Therefore, such compositions may also benefit from the addition of 1,2-alkanediols as described herein.
  • the 1,2-alkanediols described herein may also be used in the treatment of textiles and/or fibres or yarns.
  • Textiles may include woven and non-woven tissues, or combinations thereof.
  • 1,2-alkanediols described herein may further be used for the protection of agrochemical compositions.
  • the invention relates to 1,2-alkanediols obtainable by a process according to the first aspect of the invention.
  • the invention relates to 1,2- alkanediols obtained by the process according to the first aspect of the present invention. More preferably, the invention relates to bio-1, 2-alkanediols obtainable, preferably obtained, by the process according to the first aspect of the present invention.
  • Diethyl oxalate (88 g) and sodium methanolate (190 g of a 30% solution in methanol) are filled into a dry flask.
  • Ethyl heptanoate (79 g) is added and the reaction mixture is warmed to about 40 °C.
  • the methanol and ethanol being present or released during the reaction are removed by distillation under vacuum.
  • the reaction is stopped as soon as analysis by GC shows a sufficient conversion of the ethyl heptanoate.
  • the reaction mixture is cooled, and formic acid (52 g) is slowly added under vigorous stirring and temperature control ( ⁇ 40°C), followed by water (200 mL).
  • the two phases are separated.
  • the aqueous phase is extracted with ethyl acetate (2 x 50 mL). All organic phases are combined and washed with saturated hydrogen carbonate solution (50 mL) and portions of demineralised water (50 mL) until the pH of the aqueous phase is neutral (pH indicator paper Tritest ® ).
  • the solvents and excess oxalate ester are removed by vacuum distillation.
  • the oily residue is filled into a stainless-steel autoclave and mixed therein with the same volume of demineralised water.
  • the autoclave is closed and heated to 150- 200°C for 30 min. After cooling to ambient temperature, the overpressure is carefully released.
  • the phases are separated, and the organic phase is purified by fractional vacuum distillation to afford a mixture of 2-oxo-ethyl octanoate and 2-oxo-methyl octanoate (104 g, 98.1 area-% combined purity by GC-FID).
  • Diethyl oxalate (88 g) and sodium methanolate (190 g of a 30% solution in methanol) are filled into a dry flask. Excess methanol is removed by vacuum distillation. The oily residue is diluted with MTBE (150 ml_). The mixture is warmed to about 35-40 °C. Ethyl valerate (65 g) is slowly added over 2 hours and stirring is continued for 2 hours at 35-40°C.
  • the reaction is stopped as soon as analysis by GC shows a sufficient conversion of the ethyl valerate.
  • the reaction mixture is cooled, and formic acid (52 g) is slowly added under vigorous stirring and temperature control ( ⁇ 40°C), followed by water (200 ml_).
  • the two phases are separated.
  • the organic phase is washed with saturated hydrogen carbonate solution (50 mL) and portions of demineralised water (50 mL) until the pH of the aqueous phase is neutral (pH indicator paper Tritest ® ).
  • the solvents and excess oxalate ester are removed by vacuum distillation.
  • the oily residue is filled into a stainless-steel autoclave and mixed therein with the same volume of demineralised water.
  • the autoclave is closed and heated to 150- 200°C for 30 min. After cooling to ambient temperature, the overpressure is carefully released.
  • the phases are separated, and the organic phase is purified by fractional vacuum distillation to afford a mixture of 2-oxo-ethyl hexanoate and 2-oxo-methyl hexanoate (62 g, 97.8 area-% combined purity by GC-FID).
  • a mixture of 2-oxo-ethyl octanoate and 2-oxo-methyl octanoate (approx. 0.5 mol) is filled into a stainless-steel autoclave.
  • 5% Ru-catalyst on alumina is added (1 g, Noblyst® P3061) and the autoclave is closed.
  • the reaction mixture is heated to 150 °C with stirring under an atmosphere of 50 bar hydrogen. The mixture is stirred further until the end of the hydrogen absorption. Following that the reaction mixture is inertised with nitrogen and the catalyst is removed by filtration.
  • the obtained crude product is fractionally distilled in vacuo.
  • 1,2-octanediol (131 g isolated yield; purity: 99.9 area-% by GC-FID) is practically free from oxo-impurities and therefore has a very faint waxy odour. It also contains no regioisomers such as 2,3- or 3,4-octanediol.
  • a mixture of 2-oxo-ethyl hexanoate and 2-oxo-methyl hexanoate (approx. 0.5 mol) is filled into a stainless-steel autoclave.
  • Catalyst Ru-SNS catalyst C8 (155 mg) and sodium methanolate (9 g of a 30 % solution in methanol) are added.
  • the autoclave is then closed.
  • the reaction mixture is heated to 50 °C with stirring under 15-20 bar hydrogen atmosphere. The mixture is stirred further until the end of the hydrogen absorption. Following that the reaction mixture is inertised with nitrogen and neutralised with 10% sulphuric acid (24,5 g).
  • the obtained crude product is fractionally distilled in vacuo.
  • 1,2-hexanediol (53,2 g isolated yield; purity: 99.9 area-% by GC-FID) is practically free from oxo-impurities and therefore practically odourless. It also contains no regioisomers such as 2,3- or 3,4- hexanediol.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

La présente invention concerne un procédé de production de 1,2-alcanediols comprenant les étapes consistant à : fournir un oxalate de dialkyle (composant A) ; fournir un ester ou un aldéhyde (composant B), qui est caractérisé en ce qu'il comprend au moins un atome d'hydrogène lié au second atome (alpha-)carbone ; faire réagir l'oxalate de dialkyle (composant A) avec un ester ou un aldéhyde (composant B) en présence d'une base (composant C), ce qui permet de former au moins une nouvelle liaison carbone-carbone et d'obtenir un intermédiaire ; convertir l'intermédiaire obtenu en un acide alpha-céto-carboxylique, un alpha-céto-ester ou un mélange de ceux-ci ; éventuellement, réaliser une estérification de l'acide alpha-céto-carboxylique obtenu ; réaliser une réduction de l'acide alpha-céto-carboxylique ou de son ester au 1,2-alcanediol correspondant ; et éventuellement, réaliser une purification du 1,2-alcanediol obtenu et/ou de l'un quelconque des intermédiaires formés pendant les étapes précédentes.
EP22735852.0A 2021-06-23 2022-06-21 Procédé de production de 1,2-alcanediols et compositions contenant des 1,2-alcanediols Pending EP4359376A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP21181248 2021-06-23
PCT/EP2022/066838 WO2022268786A1 (fr) 2021-06-23 2022-06-21 Procédé de production de 1,2-alcanediols et compositions contenant des 1,2-alcanediols

Publications (1)

Publication Number Publication Date
EP4359376A1 true EP4359376A1 (fr) 2024-05-01

Family

ID=76584433

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22735852.0A Pending EP4359376A1 (fr) 2021-06-23 2022-06-21 Procédé de production de 1,2-alcanediols et compositions contenant des 1,2-alcanediols

Country Status (2)

Country Link
EP (1) EP4359376A1 (fr)
WO (1) WO2022268786A1 (fr)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004060541A1 (de) 2004-12-15 2006-06-29 Degussa Ag Verfahren zur Herstellung von Alkandiolen und Alkantriolen mit einer vicinalen Diol-Gruppe
WO2012052996A2 (fr) 2010-10-19 2012-04-26 Yeda Research And Development Co. Ltd. Nouveaux complexes de ruthénium et leurs utilisations dans des procédés de préparation et/ou d'hydrogénation d'esters, d'amides et de leurs dérivés
US8912373B2 (en) 2009-07-29 2014-12-16 The United States Of America As Represented By The Secretary Of The Navy Process for the dehydration of aqueous bio-derived terminal alcohols to terminal alkenes
WO2011048727A1 (fr) 2009-10-23 2011-04-28 高砂香料工業株式会社 Nouveau complexe ruthénium-carbonyle ayant un ligand tridentate et procédé de fabrication et utilisation de celui-ci
WO2019029808A1 (fr) * 2017-08-09 2019-02-14 Symrise Ag 1,2-alcanediols et procédés de production de ces derniers
US11414365B2 (en) * 2018-01-30 2022-08-16 Inolex Investment Corporation Natural 1,2-alkanediols, compositions having natural 1,2-alkanediols and processes for making the same

Also Published As

Publication number Publication date
WO2022268786A1 (fr) 2022-12-29

Similar Documents

Publication Publication Date Title
Bagheri et al. Catalytic conversion of biodiesel derived raw glycerol to value added products
Behr et al. Improved utilisation of renewable resources: New important derivatives of glycerol
Zhou et al. Recent advances in catalytic conversion of glycerol
RU2439047C2 (ru) Способ получения 1,2-пропандиола гидрогенолизом глицерина
JP5688093B2 (ja) ゲルベアルコールの製造方法
RU2436761C2 (ru) Способ получения 1,2-пропандиола гидрогенолизом глицерина
Alashek et al. Preparation of glycerol derivatives by entered of glycerol in different chemical organic reactions: a review
Da Silva et al. Fe (III)-catalyzed α-terpinyl derivatives synthesis from β-pinene via reactions with hydrogen peroxide in alcoholic solutions
CN103502190B (zh) 新型脂环族醇
DE102008013474A1 (de) Katalytisches Verfahren zur Gewinnung von chemischen Grundstoffen aus nachwachsenden Rohstoffen
Malkar et al. Development of green and clean processes for perfumes and flavors using heterogeneous chemical catalysis
KR101873838B1 (ko) 신규 지환식 알코올
EP4359376A1 (fr) Procédé de production de 1,2-alcanediols et compositions contenant des 1,2-alcanediols
Bagheri et al. Biodiesel-derived raw glycerol to value-added products: catalytic conversion approach
Shehayeb et al. Sustainable valorization of the abundant biodiesel byproduct-The glycerol
EP2943459A1 (fr) Production d'acide acrylique
WO2014138590A2 (fr) Traitement en aval de compositions d'alcool gras produites par des cellules hôtes recombinantes
TW201229014A (en) Process for preparing ε -caprolactone and 1,6-hexanediol
US20230295066A1 (en) Process for the Efficient Preparation of (Bio)-Alkanediols
DE4220939A1 (de) Verfahren zur Herstellung von 2-Aryl-ethanolen
US9394222B2 (en) Production of methacrylic acid
Green ice’
US3236901A (en) Allenic alcohols and process of manufacturing them
DE102008008389A1 (de) Methylcyclopentylester

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20240122

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)