CH624374A5 - Process for preparing liquid acetals of reduced solubility in water - Google Patents

Description

The present invention relates to a process for the preparation of acetals with a solubility of less than 10% by weight in water at 25 ° C.

It has been found that liquid acetals with a solubility of less than 10% by weight in water at 25 ° C. can be obtained in higher yields than the equilibrium concentration if special process conditions are observed.

The patent holder is not aware of any comparable procedures from the relevant literature.

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The process according to the invention for producing liquid acetals with a solubility of less than 10% by weight in water at 255 ° C. is characterized in the preceding patent claim 1.

Because of the formation of the two separate layers, the 5 reaction product in the organic phase is effectively separated from the reactants in the aqueous phase,

before equilibrium is reached. As a result, higher conversions to the acetal and higher yields are obtained than has previously been possible. The process is particularly effective in the production of acetals with o-membered rings (1,3-dioxanes) from 1,3-diols and aldehydes, since the stability of the o-membered ring accelerates a higher conversion to the acetal before equilibrium is reached. The surprisingly low solubility of 15 water in such acetals and vice versa favors layer separation. A further advantage of the process according to the invention is that it does not require large excesses of reactants that have to be recovered, that no solvents that have to be recovered are required and that no draining agents or azeotropic distillation of water with high energy consumption are required are.

It has also been found that when acrolein is reacted with 2-methyl-1,3-propanediol under the reaction conditions described above, a new acetal compound is formed which is useful as an intermediate for the preparation of butanediol and tetrahydrofuran, while the compounds mentioned in turn, are valuable in the manufacture of polyesters and as solvents.

For example, acrolein can be reacted with 2-methyl-1,3-propane-diol (MPD) to 2-vinyl-5-methyl-1,3-dioxane (VMD), which is then hydroformylated with carbon monoxide and hydrogen to acetaldehyde, which in turn is then hydrogenated and hydrolyzed to BAD and MPD. The MPD is again added to the first stage in the circuit and the BAD can, if desired, be cyclized to tetrahydrofuran (THF).

VMD education

CHo 1 y

ch2 = chcho + ho-ch2-ch-ch2oh ch = ch,

ch-

+ h20

The acrolein can be reacted with MPD using conventional reaction conditions.

According to a preferred embodiment of the process according to the invention, the acrolein is reacted with MPD in a suitable solvent, preferably benzene, and in the presence of a weakly acidic catalyst, preferably a small amount of polyphosphoric acid, with azeotropic distillation of the water. 40

The acrolein can be obtained commercially or it can be prepared from propylene by oxidation in the presence of water and oxygen using molybdenum-containing catalysts, preferably bismuth molybdate catalysts. 45

The conversions to the acetal increase with increasing chain length of the alcohol. Preferably, however, the alcohol should have a maximum of 20 straight or branched chain carbon atoms because a large number of carbon atoms could result in a solid acetal product. 50 Some alcohols which can preferably be used in the process according to the invention are, for example, 2-methyl-1,3-propanediol, 1,3-butanediol, 2,4-pentanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-l, 3-propanediol, 2-methyl-2,4-pentanediol, 1,3-pentanediol, 2,4-hexanediol, 1,3-hexanediol, 55 2,2-diethyl-l, 3-propanediol , 1,3-heptanediol, 2,4- or 3,5-heptanediol, 2,3-butanediol, 2,3-dimethyl-2,3-butanediol, 2,3-diethyl-2,3-butanediol, butyl , Amyl, hexyl, heptyl, octyl, decyl, lauryl, myristyl, stearyl, crotyl, benzyl, cinnamyl, isobutyl, isoamyl alcohol, 4-methyl-1-pentanol, 3 -Me- 60 thyl-l-pentanol, 2,3-dimethyl-l-pentanol, 2-ethyl-l-hexanol or 2-phenyl-l-ethanol, as well as mixtures of the alcohols mentioned. Alcohols containing heteroatoms such as oxygen or sulfur in the hydrocarbon structure can also be used, as well as those alcohols containing one or more of the following substituents, for example alkoxy (Q-C4), aryloxy (phenoxy, naphthoxy) ), Halogen (chlorine, fluorine, bromine, iodine), -N02 and

-SH. Some examples of such alcohols include a. 4-chloro-1-butanol, 4-bromo-l-butanol, 3,4-dichloro- or 5-chloro-l-pentanol, 4-iodo-l-butanol, 2-ethoxy-l-ethanol, 3-methoxy -1-propanol, 4-methoxy-1-butanol, 2-butoxy-1-ethanol, 3-butylthio-1-propanol, 4-methylthio-1-butanol, 3-acetoxy-1-pro-panol, 4 -Acetoxy-1-butanol, 3-nitro-1-butanol, furfuryl alcohol, 3-phenoxy-1-propanol, 2-phenoxy-1-ethanol, 2-naphthoxy-1-ethanol, 4-nitro-1 -butanol, 2- (p-nitrophenoxy) -l-ethanol, p-chlorobenzyl alcohol, and mixtures of the alcohols mentioned.

Suitable aldehydes or dialdehydes range from saturated aldehydes, starting from formaldehyde, to long-chain aldehydes. Higher molecular weight aldehydes and / or solid aldehydes can be used if they are soluble in the alcohol or any medium used for the reaction in the alcohol. The aldehyde or dialdehyde can contain the same substituents described above for the alcohols or diols. Some specific examples of suitable aldehydes and dialdehydes include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, isobutyraldehyde, isovaleraldehyde, caproaldehyde, heptaldehyde, octaldehyde, capricaldehyde and stearaldehyde and mixtures of the aldehydes mentioned.

Higher concentrations of aldehyde or larger amounts of alcohol than the stoichiometric amount bring about solubilization of the system and prevent phase separation. In addition, large excesses of unsaturated aldehyde or dialdehyde result in the formation of by-product by reaction on the double bond.

In general, the reactants are miscible liquids or one is soluble in the other so that no solvent is required to carry out the reaction. Therefore, the alcohol and aldehyde can be added as such or, if desired, they can be added in aqueous solution. However, since it is too high

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Concentration of water can cause solubility problems, the medium in which the reaction is carried out should only contain up to 10% by weight of water, based on the weight of the alcohol or diol and aldehyde or dialdehyde. However, any amount of water can be used which can be easily handled in the reaction vessel and during the separation of the two phases.

The reactions of the process according to the invention are acid-catalyzed and conventional acidic catalysts can be used. Soluble mineral acids, preferably hydrochloric acid, sulfuric acid or phosphoric acid, strongly catalyze the reaction. Organic sulfonic acids, preferably p-toluenesulfonic acid, are also excellent catalysts. Reaction mixtures using these soluble catalysts are homogeneous until phase separation begins. The disadvantage of using soluble catalysts is that they have to be neutralized before further processing of the reaction product in order to avoid hydrolysis of the product during workup. Therefore, according to a preferred embodiment of the process according to the invention, insoluble, heterogeneous catalysts are used, in particular ion exchange resins of the strongly acidic cationic type. These catalysts are particularly advantageous because they can be easily separated from the reaction product and a neutral reaction product is obtained. They have a long lifespan and can be used several times. The resins can be used either in the form of a stirred connector or as a solid layer through which the reactants are run.

Any strongly acidic, water-insoluble ion exchange resin can be used to carry out the process according to the invention. Preferred resins are those containing sulfonic acid groups, such as sulfonated styrene-divinylbenzene copolymers, which are commercially available as Dowex, Amberlite and similar resins. Other suitable cation exchange resins include the phenol sulfonic acid formaldehyde reaction products.

To carry out the method according to the invention

CH = CH "

O

+ co + h.

any suitable reactor can be used, for example a simple pot. However, a reactor with a fixed bed of an insoluble, strongly acidic ion exchange resin is preferably used as the catalyst for carrying out continuous reactions, through which the reactants are run.

The temperature in the reactor must be in the range from 0 to 100 ° C, with a temperature range from 25 to 50 ° C being preferred. In any case, the best temperature depends on the reactants used. At temperatures below 25 ° C, the conversion rate may be too slow for commercial use. At temperatures above 50 ° C unsaturated aldehydes, e.g. Acrolein, for side reactions.

After the reaction has ended, any device which is suitable for separating the organic phase from the aqueous phase can be used. Since the process according to the invention can be carried out batchwise or continuously, the phase separation can also be carried out batchwise or continuously. In a batch process, the reaction layers can be separated by letting the lower, aqueous layer run off from the acetal layer 25 in a separating funnel (or on a larger technical scale in a corresponding device). In a continuous process, the reaction products can be fed to a decanter by continuously separating the layers.

Of the acetals described above, those with an olefinic double bond can be reacted with hydrogen and carbon monoxide by means of hydroformylation to give the corresponding aldehyde. In particular, the new acetal compound 2-vinyl-5-methyl-1,3-dioxane (VMD) is converted to new acetaldehydes with hydrogen and carbon monoxide, 2 (2'-pro-35 panal) -5-methyl-1,3,3 dioxane and 2 (3'-propanal) -5-methyl-1,3-dioxane implemented. These acetal aldehydes are valuable intermediates for the production of 1,4-butanediol and tetrahydrofuran. This hydroformylation is explained below using VMD as an example.

ch2ch2cho ch3chcho

O

O

O

CH-

ch.

ch-

2 (2'-propanal) -5-methyl-1,3-dioxane and / or 2 (3'-propanal) -5-methyl-1,3-dioxane) is referred to in this description as PMD. The known reaction conditions for carrying out hydroformylations can be used to carry out this reaction.

According to a preferred embodiment, VMD is reacted either in a continuous or batch reaction with hydrogen and carbon monoxide in a molar ratio of H2: CO from 0.9: 1 to 1.2: 1, preferably 1: 1. At ratios of less than 0.9: 1, the reaction rates are too slow for commercial use; at ratios greater than 1.2: 1, the hydrogenation of VMD occurs as an undesirable side reaction. Best yields are achieved at the preferred ratio.

The preferred hydroformylation reaction is carried out in the presence of a rhodium carbonyl complex catalyst at a molar ratio to VMD of 0.5 × IO "3: 1 to 6.0 X 10-3: 1, preferably 1.0 x 10" 3: 1. With these preferred ratios, optimal yields and reaction rates are achieved. The rhodium complex catalyst forms on site when rhodium in the form of Rh6 (CO) i6 is added to the hydroformylation reaction mixture containing the ligand described below. The same rhodium carbonyl complex with a trialkylphosphite can also be prepared first and then added to the reaction mixture.

The phosphite ligand 60 used in the hydroformylation has the formula R! 0-P (0R2) -0R3, in which Rx, R2 and R3, which are the same or different, are alkyl groups having 1 to 12 carbon atoms, preferably methyl, ethyl, propyl, octyl, Pentyl, decyl, or dodecyl, or phenyl. To make the operation easier, it is preferred if 65 Ri, R2 and R3 are the same. It is particularly preferred if R 1, R 2 and R 3 are the same alkyl groups with 1 to 3 carbon atoms, for example trimethyl phosphite, triethyl phosphite, tri-n-propyl phosphite and triisopropyl phosphite

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these substances have a low boiling point and can be easily separated, cleaned and added to the system again. However, it is also possible to use higher-boiling phosphites which correspond to the abovementioned formula, for example tri-n-butylphosphite, tri-isooctylphosphite, dimethyldodecylphosphite, tridecylphosphite, triphenylphosphite, methylethylpropylphosphite, dimethylphenylphosphite or methylpropylphenylphosphite or any other combination, any combination, as well as any combination, definition or any other phenylphosphite the above formula and mixtures of the compounds mentioned, io

The phosphite ligand forms a complex with rhodium and carbon monoxide, and this complex catalyzes the hydroformylation reaction. To prevent isomerization of the double bond in the VMD and to maximize the yield of linear aldehyde in the reaction, an excess of phosphite over the amount required to complex with the rhodium must be used. The excess ligand is also required to guarantee the stability of the rhodium catalyst during the reaction. In general, a molar ratio of phosphite ligand to rhodium of 5: 1 to 50: 1 is used. In order to obtain optimal reaction rates and to obtain a product which favors the formation of butanediol in the hydrolysis and hydrogenation, it is preferred that a ligand: rhodium molar ratio of 10: 1 to 20: 1 is used.

The hydroformylation reaction can be carried out batchwise or continuously, using any suitable reactor, for example a simple low pressure reactor. To facilitate the operation, it is preferred that the reaction be carried out in a continuous reaction reactor through which the acetal flows in parallel to the flow direction of the carbon monoxide and the hydrogen gas. The reactor pressure should be in the range from 5.2 to 10.5 kg / cm 2, preferably 7 to 7.73 kg / cm 2, gauge pressure. The reaction temperature should be in the range from 85 to 115 ° C., preferably 100 to 110 ° C., and the residence time in the reactor should be 0.5 to 5 hours, preferably 1 to 2 hours. The highest yields and the best reaction rates are observed under the preferred conditions.

After the product stream has left the reactor, the ligand is separated off in any suitable manner, preferably by distillation. When the preferred ligands are used, the reaction product is preferably fed into a ligand stripping column maintained at a pressure of 10 mm and a temperature of 110 ° C. Excess ligand is removed and returned to the reactor. The product stream is then fed into an aldehyde evaporation column which is kept at a pressure of about 8 mm and a temperature of 120 ° C. The aldehyde product is distilled off to be used in the hydrolysis-hydrogenation reaction. To prevent aldehyde decomposition, the temperature at this stage should not exceed 120 ° C and the aldehyde residence time should be less than 55

be less than 5 minutes. The product from the column bottom of this separation stage contains some high-boiling by-products, the formation of which is inevitable, and the entire rhodium catalyst. This product is returned to the reactor after removal of a small portion, such as one eighth, as a purge stream to combat the build up of high boiling products. While it has been said that the presence of these high-boiling components is advantageous in some cases, it has been found that an acceptable maximum concentration of high-boiling substances according to the invention is about 50%, preferably 25%.

By hydrolysis and hydrogenation of the hydroformylation reaction product, BAD is produced together with certain by-products. The reaction product of acetaldehyde hydroformylation can be hydrolyzed and hydrogenated using methods known per se. According to a preferred embodiment, water is mixed with the reaction product of the acetalaldehyde hydroformylation, and the mixture is introduced into a hydrogenation reactor at a pressure of 7 to 352 kg / cm 2 gauge pressure and a water: aldehyde molar ratio of 1: 1 to 20: 1 fed. The functional aldehyde group is reduced to the corresponding alcohol in the presence of a catalytic amount of any hydrogenation catalyst, preferably Raney nickel. It is believed that as the reaction proceeds, the acetal ring breaks down to give BAD and MPD, which can be separated by conventional distillation methods. The MPD can be recycled into the process and used for the production of the cyclic acetal according to the invention. The BAD can be cleaned and used as such, for example as a crosslinking agent to make polyurethane polymers, or it can be heated in a cyclization column to make, for example, tetrahydrofuran.

It has also been found that the hydrogenation and hydrolysis can advantageously be carried out by first hydrogenating the organic compound containing a six-membered acetal ring and an aldehyde group at elevated temperature in the presence of a catalytic amount of a hydrogenation catalyst to give the corresponding acetal alcohol. which is then simultaneously hydrolyzed and hydrogenated in aqueous medium in the presence of hydrogen and a hydrolytic amount of a strongly acidic, water-insoluble ion exchange resin and a catalytic amount of a hydrogenation catalyst to give the corresponding polyols. If desired, the hydrolysis-hydrogenation can be continued via the formation of the polyol hianus.

This prehydrogenation of the cyclic acetal aldehyde can be illustrated, for example, by the following reaction scheme, wherein 2- (3'-propanal) -5-methyldioxane (PMD) is used as a typical example of the cyclic acetal aldehydes described herein:

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40

45

Î

H-C-CH2-CH2-CH

/ \

o ch

Hydrogenation ch-cho + h „'^. ■ ->

3 2 catalyst a o ch,

Oh

0 ch

ch2-ch2-ch2-ch ch-ch,

o ch,

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6

OH O CH2

I / \ ion exchange resin

II CH2-CH2-CH2-CH ^ CH-CH3 hydrogenation catalyst P.

o ch2 a

HO-CH2-CH-CH2-OH + ED (CH2) 40H

ch3

and optionally

H2? - ÇH2

, Ion exchange resin. > i + «• o

III HO (CH) OH> HC CH_ + 2

^ & 2 \ y 2

O

This prehydrogenation precludes the formation of insoluble bisacetals, which cause lower yields in a single-stage hydrolysis hydrogenation. In a one-step reaction, bisacetal formation competes with the hydrogenation of the free aldehyde, which is too slow to produce the bisacetal

CH.

ch3-ch

\

ch.

To prevent 20 tals. Bisacetals are formed by reacting the free 1,3-diol with the starting aldehyde acetal as explained below, again using PMD as an example:

ch-cho-ch "-ch0 + ch,

'2. 2. j ^

OH

ch-

ch

[h +]

ch

2 «= -

OH

CH,

ch3-ch

\

CH.

ch-ch2-ch2-ch.

-CH,

CH,

ch-ch-

The bisacetals tend to be insoluble, especially at temperatures below their formation temperature, and as a result they precipitate out during the process. In the case of continuous, technical processes in particular, the amount of precipitate which settles out after several cycles can be so great that it clogs the apparatus, which necessitates interruption, cleaning and a new start. However, it was completely unexpected that the prehydrogenation of the cyclic acetaldehyde could solve this problem without any major difficulty, since it is known per se that acetal groups form ether bonds during the hydrogenation, cf. for example, “Reactions of hydrogen with organic compounds over copper, chromium oxide and nickel catalysts” by Homer Adkins, p. 75. Since the ether bond is stable during hydrolysis, it would be expected that prehydration would negate the object of the present invention. Contrary to this expectation, it was found that polyols can be easily and effectively prepared without the formation of bisacetals and without formation of ethers by hydrogenating the acetal aldehyde before the hydrolysis-hydrogenation.

The term "polyol" is understood to mean diols and triols and compounds with a larger number of hydroxyl groups.

The acetalaldehydes to be hydrogenated and hydrolyzed have the following formula:

45

55

60

65

50

wherein X is the group -CHO or -CHO, where M is an alkyl group, preferably an alkyl group having 1 to 20 carbon atoms, the -CHO group can be linked to any M carbon atom which has a replaceable water stream, Rx , R2, R3, R4, Rs and R6, which are the same or different, are hydrogen or an alkyl group, preferably an alkyl group having 1 to 20 carbon atoms.

Although M, Rj, R2, R3, R4, Rs and R6 can also mean alkyl groups with more than 20 carbon atoms, an upper limit of 20 carbon atoms is preferred in order to exclude compounds with too high a molecular weight. The alkyl groups can also contain any substituents provided they do not interfere with the hydrolysis-hydrogenation.

Some preferred examples of acetal aldehydes which can be hydrolyzed and hydrogenated by the processes described include:

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(C1 ~ C20)

^ ch (c1-c20) cho ch-ch "-ch" -cho y 2 2

- O,

h "c ch-ch2-ch2-cho ch-cho-ch" -ch0

/ 2 2

(ch,)

3 2

(fH-

w ch-ch2-ch2-cho h-.c

0 ^ cho ch-ch-ch-

/

-o cho ch-ch-ch-

(CH3) 2

Any catalytically effective amount of any metal or compound known as a hydrogenation catalyst can be used in the prehydrogenation. It is desirable to use as the hydrogenation catalyst a metal or a compound of a metal which can be easily and economically manufactured, which has a high degree of activity and which maintains its activity under the process conditions for so long as to avoid the need to reactivate or renew the Avoid catalyst at short intervals. Generally speaking, the hydrogenation catalysts which can be used in carrying out the process mentioned include the metal hydrogenation catalysts, such as platinum, palladium, gold, silver, copper, vanadium, tungsten, cobalt, nickel, ruthenium, rhodium, manganese, chromium, molybdenum, Iridium, titanium, zirconium and similar metals, as well as mixtures of these metals and compounds and alloys thereof, in particular oxides and sulfides, and similar hydrogenation catalysts. Because of the ease and economy with which they can be made, the base metal hydrogenation catalysts such as nickel, cobalt and iron are preferred. Nickel aluminum alloys that are activated by partial removal of the aluminum with sodium hydroxide solution are particularly important. The hydrogenation catalyst can be used in finely divided form dispersed in the reaction mixture; or the catalyst can be used in a more solid state, either in a practically pure state or on an inert or catalytically active support material, such as pumice stone, diatomaceous earth, diatomaceous earth, clay, alumina, activated carbon, coal or the like; the reaction mixture can be contacted with the catalyst by flowing the mixture over or through a bed of the catalyst or by any other method known in the art.

The prehydrogenation is preferably carried out at elevated temperature and under elevated hydrogen pressure. If desired, the prehydration can be carried out in an aqueous medium; in this case water serves as a heat exchange medium and for adjusting the viscosity, although the reaction is also undiluted, i.e. without the use of water. If an aqueous medium is used, it is advantageous to have enough water for the hydrolysis-hydrogenation stage, i.e. a molar ratio of water to acetal aldehyde of 1: 1 to 100: 1, preferably 1: 1 to 10: 1. Hydrogen pressures of 35 to 703 kg / cm 2, preferably 70 to 352 kg / cm 2, and temperatures in the range of 40 to 150 ° C. are generally used for the prehydrogenation.

The acetal alcohol thus formed is then hydrolyzed and hydrogenated in an aqueous medium. If no water is used in the prehydrogenation, this is now added in a 45 molar ratio of water to acetal alcohol from 1: 1 to 100: 1, preferably 1: 1 to Ì0: 1. A hydrogen pressure of 35 to 703 kg / cm2, preferably 70 to 352 kg / cm2, and a temperature in the range of 30 to 165 ° C, preferably 65 to 150 ° C, are used.

The hydrogenation catalysts specified for the prehydrogenation stage can also be used in the hydrolysis-hydrogenation. Any strongly acidic, water-insoluble ion exchange resin can be used in the hydrolysis-hydrogenation. Preferred resins are those containing sulfonic acid groups, for example those containing sulfonated styrene-divinylbenzene copolymers and are commercially available as Dowex MSC-1, 50 and 50 WX8, Amberlyst 15 and the like. Other suitable cation exchange resins include the phenolsulfonic acid-formaldehyde reaction products.

The insoluble resin and the hydrogenation catalyst forming the catalyst system can be in various interrelationships as desired, but a weight ratio of insoluble resin to hydrogenation catalyst of 0.1: 1 to 100: 1, preferably 1: 1 to 10: is preferred. 1.

Depending on the desired product and the type of reaction system used (connection, fixed bed, etc.),

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any hydrolytically-catalytically effective amount of the catalyst system can be used. In general, such amounts of acid catalyst system are used that 1% by weight of hydrogenation catalyst, based on the weight of the acetal alcohol, is present. In the case of a slurry system, I to 10 percent by weight, based on the contents of the reactor, is optimal, and in the case of a fixed bed reactor 10 to 20 times the amount can be used.

The reaction can be carried out either continuously or in batches. In any case, the time during which the reactor contents are in contact with the catalyst system depends on the desired product. By changing the temperature and contact time, either polyol product or the cyclized form of any polyol capable of cyclization in a strongly acidic medium, or any combination thereof can be obtained. If the temperature is increased and the contact time is extended, the cyclization reaction is favored. Taking BAD as an example, cyclized BAD (THF) can be obtained at higher temperatures and longer contact times with more than 90% yield, while 99% yields of BAD can be obtained at low temperatures and shorter contact times. Any correlation between temperature and contact time from 3 hours at 60 ° C to half an hour at 150 ° C can be observed. At 130 ° C or higher, THF forms very quickly and preferably.

Surprisingly, it has also been found that organic compounds containing a six-membered acetal ring and an aldehyde group in an aqueous medium in the presence of hydrogen and a catalyst system consisting of a hydrolytic amount of a strongly acidic, water-insoluble ion exchange resin and a catalytic amount of a hydrogenation Metal or metal compound catalyst exists, can be hydrolyzed and hydrogenated in a single step to the corresponding polyols. If desired, this reaction can be continued beyond polyol formation to achieve cyclization of those polyols that are capable of cyclization in the presence of a strong acid, for example cyclization of 1,4-butanediol (BAD) to tetrahydrofuran (THF).

The acetal aldehydes, which can be hydrolyzed and hydrogenated in a single step, contain a six-membered acetal ring and a functional aldehyde group which is linked directly or indirectly to the acetal ring by a cyclic or acyclic, saturated or unsaturated group, the group in turn being linked to the Carbon atom of the acetal ring is linked, which separates the oxygen atoms in the acetal ring.

A steam mixture consisting of propylene, oxygen and water in a molar ratio of 2: 1: 3 (propylene: oxygen: water) is continuously at a rate of 4 liters of steam per 100 grams of catalyst per minute (corrected to standard temperature and pressure) continuously fed into the reactor. The reactor contains a bismuth activated strontium-molybdenum precipitated catalyst consisting of oxides of molybdenum, strontium and bismuth in a molar ratio of 1.05: 1: 0.05 (molybdenum: strontium: bismuth). The temperature of the reaction zone is kept at 500 ° C. As determined by gas chromatographic analysis, 29% of the propylene was converted to 53% acrolein based on the amount of propylene. The exit gas stream also contains CO, C02, 02, unreacted propylene and a very small amount of other oxidized compounds. Repeating the process using a larger amount of water (water to propylene molar ratio of 5: 1) gives a higher percentage of propylene conversion; the percentage yield of acrolein remains approximately unchanged. Preferred embodiments of the invention are explained in more detail below with the aid of examples. Unless otherwise stated, all information in "parts" and "percent" is weight.

Example 1 2-vinyl-5-methyl-1,3-dioxane (VMD)

A mixture of 1 mole equivalent of 2-methyl-l, 3-propane-diol (MPD) and 1.1 mole equivalent of acrolein was run at a rate of 0.55 g / min. passed through a column (6.35 x 152 mm) of 10 ml of a strongly acidic cation exchange resin (Dowex MSC-1). The bed was cooled with circulating water at 25 ° C and the maximum temperature of the resin bed was 35 ° C. The reaction product (30.7 g) was separated into 2 layers - an acetal layer (26.6 g) and an aqueous layer (4.1 g). The layers were both analyzed by gas-liquid phase chromatography. The acetal layer contained 79% VMD, 3% MPD, 8% acrolein and 3% water. The aqueous phase contained 61% water, 22% MPD, 8% acetal and 4% acrolein. Thirty-eight percent of the MPD had been converted to acetal. The yield, based on converted acrolein, was 96%.

A similar reaction between MPD and acrolein was carried out at a rate of 1.32 g / min. carried out. The maximum temperature observed in the resin bed was 48 ° C. The reaction product (30.7 g) separated into an acetal phase (26.3 g) and an aqueous phase (4.4 g). The conversion from MPD to acetal was 82%. The compositions of the two layers were similar to the above.

Example 2

The addition of 0.05 ml of 37% hydrochloric acid to a mixture of 18.02 g (0.20 mol) of 2-methyl-1,3-propanediol and 12.12 g (0.216 mol) of acrolein at 30 ° C. gave one rapid temperature increase to 48 ° C. The temperature was reduced to 30 ° C. by cooling and kept at this temperature for 2 hours by further cooling. The reaction mixture was divided into two layers - 25.62 g acetal layer and 4.84 g aqueous layer. The conversion to acetal was 89%, of which 98.8% was present in the acetal layer. The acetal layer contained 88% VMD, 14% water, 6.8% acrolein and no diol. The aqueous layer contained 5% VMD, 21% diol, 62.6% water and 3.8% acrolein.

Example 3

The reaction of 26 g (0.25 mol) of 2,2-dimethyl-1,3-propanediol and 15.4 g (0.275 mol) of acrolein was catalyzed with 0.1 ml of 37% hydrochloric acid. At a controlled reaction temperature of 35 to 40 ° C, the separation into two layers began within 2 minutes. The conversion to acetal was 92%. A similar reaction at 27 ° C gave two layers within 40 minutes and gave the same conversion to the acetal. The acetal layer contained 87.7% 2-vinyl-5,5-dimethyl-1,3-dioxane (VDD), 1.0% diol, 1.0% water and 3.5% acrolein. The aqueous layer contained 1.0% VDD, 18% diol, 1% acrolein and 77% water.

Example 4

A mixture of one molar equivalent of 2,2-dimethyl-1,3-propanediol, 1.1 molar equivalent of acrolein and 1 molar equivalent of water was passed through a column (19.05 x 101.6 mm) of 40 ml of strongly acidic cation exchange resin (Dowex MSC- 1) at a speed of 5 g / min. let run. The maximum temperature in the resin bed was 55 ° C when the bed was cooled by circulating water at 25 ° C. A sample of 91.8 g of the eluate separated into two layers - an acetal layer of 71.4 g and an aqueous layer of

5

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50

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20.3 g. The acetal layer consisted of 88.8% acetal (VDD) and small amounts of diol, 4% acrolein, 3% water and by-products. The aqueous layer consisted of 83.1% water, 13.7% diol, 2.2% acetal and 1.8% acrolein. The conversion to acetal was 89%.

Example 5

In this example, 2.0 molar equivalents of water with 1.0 molar equivalent of 2,2-dimethyl-1,3-propanediol and 1.1 equivalents of acrolein were used. The resin bed was the same as that used in the previous example. At a flow rate of 2.7 g / min. and with cooling, the maximum temperature of the resin bed was 30 ° C. A 100.8 g sample separated into 65.4 g acetal layer and 35.4 g aqueous layer. The conversion to acetal was 82%. The acetal layer contained 89.2% VDD, 0.4% diol, 1.2% water and 5% acrolein. The aqueous layer contained 3% VDD, 14% diol, 80% water and 2% acrolein.

Example 6

A mixture of 1.0 mole equivalent of 1,3-butanediol and 1.15 mole equivalent of acrolein was passed through a bed of 10 ml of the ion exchange resin of Example 1 (grain size 0.149 to 0.279 mm) at a rate of 0.65 g / min. let run. The maximum temperature in the resin bed with cooling was 52 ° C. An eluate sample of 104.4 g separated into 88.5 g acetal layer and 15.9 g aqueous layer. The conversion to 2-vinyl-4-methyl-1,3-dioxane was 88%. The acetal layer contained 85.2% 2-vinyl-4-methyl-1,3-dioxane, 2.7% diol, 3.3% water and 6.7% acrolein. The aqueous layer contained 8.6% 2-vinyl-4-methyl-1,3-dio-xane, 66.8% water, 20.9% diol and 6.2% acrolein.

Example 7

A mixture of 0.50 mol of 2-methyl-2,4-pentanediol, 0.55 mol of acrolein and 0.2 g of polyphosphoric acid reacted into two layers within 20 minutes at 50 ° C. The conversion to acetal was 92%. The acetal layer contained 90.5% 2-vinyl-4,4,6-trimethyl-1,3-dioxane, 6% acrolein, 2% diol and 1.5% water. The aqueous layer contained 3.6% acrolein, (1% 2-vinyl-4,4,6-trimethyl-l, 3-dioxane and 75% water.

Example 8

A mixture of 0.2 mole of 1,3-butanediol and 0.2 mole of acetaldehyde was stirred over 45 g of the resin of Example 1 without heat at 45 to 75 ° C. The reaction mixture separated into 21.0 g acetal layer and 3.5 g aqueous layer. Conversion to acetal (2,4-dimethyl-1,3-dioxane) was 90%. The acetal layer contained 96% 2,4-dimethyl-1,3-dioxane, 1.3% diol, 0.6% acetaldehyde and 2% water. The aqueous layer contained 41.5% water, 0.8% acetaldehyde, 22% diol and 32% 2,4-dimethyl-1,3-dioxane.

Example 9

A mixture of 0.4 mol of n-amyl alcohol, 11.6 g of propionaldehyde and 0.1 mol of 37% hydrochloric acid was reacted at 35 to 40 ° C. Two layers formed within 5 minutes. The separation of the layers gave 45.2 g of acetal layer (composition: 6% propionaldehyde, 23% amyl alcohol and 70% acetal). The conversion to acetal was 72%.

Example 10

A mixture of 0.6 mol of n-butyl alcohol, 0.3 mol of acetaldehyde and 0.1 ml of 37% hydrochloric acid was reacted at 45 to 50 ° C. The separation into two layers took place within 1 minute. The aqueous layer weighed 1.7 g. The conversion to acetal was 66 to 69%. The acetal layer contained

67.5% di-n-butyl acetal, 26% n-butyl alcohol and 6% acetaldehyde.

Example 11

A mixture of 10.6 g (0.151 mol) of methacrolein and 14.4 g (0.138 mol) of 2,2-dimethyl-1,3-propanediol was based on at 25 to 40 ° C in the presence of 0.1% hydrogen chloride the total weight of the reactants, stirred. Two layers separated within 10 minutes. The acetal layer (23.5 g) contained 85.4% 2- (2-propenyl) -5,5-dimethyl-1,3-dioxane, 9.4% methacrolein, 1.6% water and 1.4 % Diol. The aqueous layer (2.89 g) contained 75% water, 15% diol and 2% methacrolein. The conversion of the diol to the acetal was 93.5%.

Example 12

A mixture of 21.2 g of formaldehyde (0.20 mol) and 18.0 g of 1,3-butanediol (0.20 mol) was reacted in the presence of 0.1% hydrogen chloride, based on the total weight of the reactants. The mixture separated into two layers - an aqueous layer of 5.1 g and an acetal layer of 33.3 g. The aqueous layer contained 53% water and 44% 1,3-butanediol. The acetal layer contained 1% water, 8.5% aldehyde and 90% 4-methyl-1,3-dioxane. The conversion to acetal was 82%.

Comparative data

(1) The procedure of Example 1 was repeated except that a mixture of 0.5 mol of 1,3-propanediol and 0.55 mol of acrolein was reacted at 50 ° C in the presence of 0.3 g of p-toluenesulfonic acid. The layers did not separate until the reaction mixture was cooled to 26 ° C. The mixture gave 18 g of an aqueous layer containing about 40% diol, 21% acrolein, 10% 2-vinyl-l, 3-dioxane and 25% water. The acetal layer (49 g) contained 63% 2-vinyl-l, 3-dio-xane, 23% acrolein, 8% diol and 5% water; the conversion to acetal was about 60%, which is only a negligible increase over the equilibrium conversion.

(2) A mixture of 4.50 g (0.050 mol) of 2-methyl-l, 3-propanediol and 1.73 g (0.030 mol) of acrolein with 0.01 g of p-to-toluenesulfonic acid was at 40 to 50 ° C implemented to illustrate the use of less than a stoichiometric equivalent amount of aldehyde. The reaction mixture did not separate into two layers. Analysis of the reaction mixture by gas chromatography showed that 73% of the acrolein had been converted to the acetal. When equimolar amounts of the reactants were used as in Example 2, separation occurred in two layers and the conversion to acetal was 89%.

Example 13 VMD formation

About 45 g (0.5 mol) of MPD was reacted in the presence of 0.2 g of polyphosphoric acid as a catalyst with azeotropic distillation of the water for 30 minutes in 100 ml of benzene with 30.8 g (0.55 mol) of acrolein until the water distillation was finished. The liquid product was separated and analyzed by gas chromatography. Analysis of the product showed 87% conversion to VMD. The distilled VMD product had a boiling point of 62 ° C at 24 torr.

Hydroformylation

15.4 g (0.12 mol) of VDM, 0.025 g (2.3 x 10'5 mol) of hexa-rhodium hexadecacarbonyl and 250 β / trimethyl phosphite were placed in a 400 ml lined glass autoclave with a stirrer under an atmosphere of dry nitrogen. The molar ratio of trimethyl phosphite to rhodium was 14.3: 1. The autoclave was then washed with a 1: 1 mol

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

624 374

10th

Ratio of carbon monoxide-hydrogen gas to a pressure of 6.68 kg / cm2 (95 psig). The contents were heated to 110 ° C and the pressure was adjusted to 7.38 kg / cm 2 (105 psig) and maintained at this level during the reaction. After 55 minutes, 96% of the theoretical amount of gas had been absorbed by the reaction mixture. Then the autoclave was cooled and the excess gas was released. The liquid ingredients were removed and analyzed by gas chromatography. Analysis of the product showed 97% conversion of VMD to 2- (3'-propanal) -5-methyl-1,3-dioxane and 2- (2'-propanal) -5-methyl-1,3-dioxane . About 80 mol% of 2- (3'-propanal) -5-methyl-1,3-dioxane and 12 mol% of 2- (2'-propanal) -5-methyl-1,3-dioxane were obtained. The aldehydes had a ratio of normal: iso of 87:13.

Hydrolysis-Hydrogenation 36.4 g of the aldehydes prepared as above are mixed with 30 ml of a 10% aqueous acetic acid solution and at 100 ° C. and a pressure of 70.3 kg / cm 2 (1,000 psig) using 3 g of 10% palladium / Active carbon hydrolyzed and hydrogenated. The reaction product is filtered off and the water and acetic acid are removed by distillation. Gas chromatographic analysis of the reaction product shows that MPD (96% yield) and BAD (98% yield) were formed by the reaction; 0.229 moles of MPD and 0.180 moles of BAD are obtained. The MPD is again added to the acetal formation step and the BAD is cyclized to THF in the presence of concentrated sulfuric acid.

Examples 14 to 18

Example 13 is repeated, except that acrolein is reacted with 0.5 mol of diols, which differ from MPD in Examples 15 to 18.

Table 1 Acetal formation

example

Diol

Acetal

14

MPD

VMD

15

2,2-dimethyl-1,3-propanediol

2-vinyl-5,5-dimethyl-1,3-dioxane

16

2-methyl-2,4-pentanediol

2-vinyl-4,4,6-trimethyl-1,3-dioxane

17th

1,3-butanediol

2-vinyl-4-methyl-1,3-dioxane

18th

2,3-propanediol

2-vinyl-4-methyl-1,3-dioxane

Table II Hydroformulation

For example, play bond

Ligand

Ligand / Reak Rhations-

time

Products (mol.%)

14

2-vinyl-5-methyl-1,3-dioxane 15.4 g 0.12 mol

15

16

200 / d 11.4: 1 53 min. (CH3Ü) 3P

2-vinyl

5.5 di

methyl-

1,3-dioxane

17.1g

0.12 mol

250 / il 14.3: 1 56 min. (CH30) 3P

2-vinyl

4,4,6-tri-

methyl-

1,3-dioxane

18.8g

0.12 mol

250 «1 14.3: 1 60 min. (CH30) 3P

CH-CH-CHO CH-CHCHO CH = CH "CH ^ CH

22 X.

.-V

o o

2 JZ? 3rd

> 0 0 0 0 0

3 76% A

ch3

10% B

CH.

CH_CH_CHO CH-CHO

0 ^: 2 «rS

V ... V.

CH. 4%

CH = CH.

<A>

V.

H3c CH3 h3c CHj h3c ch3 h3c

CH. 4%

CH0CH,

X.2 3

O 0

• x *

CH_

76% A

12%

B

CH,

I 3

3%

5%

b3c

CH2CH2CH0 CHCHO CH = CH2

CH-CH,

-Aj2 3

o. CH.

h_c ^ h-c \ h.c p «

^ 3 CEij ^ CI ^ 3 3

77% 12% 2% 5%

A B

Î1

Table II (continued)

624 374

For- V er ligand ligand, reak products (\ lol. 'R1

game binary

duna time

17 2-vinyl- 250 / d 14.3: 1 43 min. CH CH-CHO CHCHO CH = CH0 CH-CH,

4-methyl- (CH3Ü) 3P A / '1' '' '3

1,3-dioxane q q

CH3

76% 14% 8% 3%

A B

15.4 g 0.12 mol

18th

2-vinyl-4-methyl-1,3-dioxolane 13.7 g 0.12 mol

250 // I (CH30) 3P

14.3: 1 52 min.

CHoCHoCH0

X2 2

0 0

CH.

81% A

Table III Hydrolysis-hydrogenation

Example quantity A and B '/ b Um-% Um- products (mol.%)

Change A Change B

14 36.4 g (0.23 mol) 86 42 C 1,4-butanediol (70.2)

(87% A, 137o B) D 2-methyl-1,3-propanediol (71.6)

15 39.6 g (0.23 mol) 90 50 C 1,4-butanediol (73.5)

(86% A, 14 '/ t-B) D 2-methyl-1,3-propanediol (6.5)

E 2,2-dimethyl-1,3-propanediol (80.0)

16 42.8 g (0.23 mol) 90 50 C 1,4-butanediol (74.4)

(87% A, 13% B) D 2-methyl-1,3-propanediol (6.2)

E 2-methyl-2,4-pentanedioI (80.6)

17 36.4 g (0.23 mol) 87 45 C 1,4-butanediol (71.9)

(87% A, 13% B) D 2-methyl-1,3-propanediol (5.8)

E 1,3-butanediol (77.6)

18 33.2 g (0.23 mol) 90 50 C 1,4-butanediol (74.4)

(87% A, 13% B) D 2-methyl-1,3-propanediol (6.0)

E 1,2-propanediol (79.0)

In contrast to the results obtained in Examples 14 and 15, Examples 16 to 18 give more than two 55 diols. Furthermore, the diols produced in Examples 16 to 18, which are not BAD, are not suitable for use in the production of VMD according to the inventive method, as is the MPD of Examples 14 and 15, for example. 60

Further hydrogenation processes are described below.

Procedure 1

A 300 ml autoclave equipped with a stirrer is charged with the following components: 65

Isomer mixture of 2- (ß and y formylethyl) -5,5-dimethyl-

1,3-dioxane (70% y) 50 g

Water 50 g

Raney nickel (wet solids) 5 g

Dowex 50WX8 10 g

Dowex 21K lg

The autoclave is then closed, filled with hydrogen up to a hydrogen pressure of 105 kg / cm 2 and heated to 90 ° C. for 30 minutes. Upon completion of this reaction time, gas chromatographic analysis showed that 95% of the dioxane had been converted to a mixture of glycols. There was a 97% yield of 1,4-butanediol (BAD), while tetrahydrofuran (THF) was only present in traces.

Procedure 2

A 300 ml autoclave equipped with a stirrer is charged with the mixture according to method 1: 45 g

624 374

Water 50 g

Raney nickel (wet solids) 5 g

Dowex 50WX8 resin 10 g

The autoclave is closed, brought to a pressure of 105 kg / cm 2 with hydrogen and kept at this pressure at 100 ° C. for 25 minutes. At this point a gas chromatography test showed virtually complete conversion of the dioxane to 1,4-butanediol. The temperature was raised to 120 ° C and held at this temperature for 30 minutes. At the elevated temperature, 60% of the 1,4-butane andiol was converted to THF.

Procedure 3

Procedure 1 was repeated except that the amount of Dowex 50WX resin was increased from 10 to 20 g. After 30 minutes, 100% of the dioxane was converted. Gas chromatographic analysis showed that the product contained 15% THF based on the concentration of 1,4-butanediol in the final mixture.

Procedure 4

Procedure 1 was repeated, except that the amount of Ra-ney-nickel was increased from 5 to 12 g. Virtually the same results as reported in Example 19 were obtained.

Procedure 5

A continuous process is carried out as follows: The autoclave is charged with:

Ethylene glycol water

Raney nickel (wet solids) Dowex 50WX8 resin Dowex 21K resin

30 g 30 g 5 g 10 g 0.5 g

15

Procedure 6

A 300 ml autoclave equipped with a stirrer is charged with the following substances:

2- (ß, y-formylethyl) -5-methyl-1,3-dioxane

(80% y) 50 g

Water 50 g Dowex MSC-1 resin (a

Sulfonic acid ion exchange resin) 15 g

Nickel (Raney; wet solids) 10 g

The temperature is raised to 130 ° C and the pressure to 141 kg / cm2. After 1 hour, the conversion of the dioxane is complete under these conditions. The 1,4-butanediol obtained is cyclized to 93% to THF. The yield of THF and butanediol, based on the amount of y-formylethyl isomer used, is 97%.

The autoclave is then closed and the pressure is brought to 112 kg / cm 2 and the temperature to 90 ° C. and kept at these values. Then a mixture of isomers of 2 - (/ 3, y-formylethyl) -5,5-dimethyl-1,3-dioxane (60% y) is pumped into the autoclave at a rate of 60 g per 40 minutes. A sample taken after 40 minutes shows that the conversion of the dioxane is 80% at this point. After the addition is complete, the reaction is allowed to continue for 30 minutes. After this time, the dioxane conversion to glycols is 97%. To. At this point the nickel is removed and the reaction mixture is heated to 140 ° C in a distiller to convert all 1,4-butanediol to THF which is distilled off. The yield of THF, based on the y-isomer in the dioxane used, is 91%.

Procedure 7

20 40 g of a mixture of the monocyclic acetals, 2- (3'-propanal) -5,5-dimethyl-l, 3-dioxane (90%) and 2- (2'-propanal) -5,5-dimethyl -1, 3-dioxane (10%) are hydrogenated at 60 ° C., 5 g of Raney nickel being added and the hydrogen pressure being 176 kg / cm 2. The reaction time is 50-25 minutes and the aldehydes used are completely converted to the corresponding alcohols, i.e. the monocyclic acetals 2- (3'-propanol) -5,5-dimethyl-1,3-dioxane and 2- (2'-propanol) -5,5-dimethyl-1,3-dioxane.

The mixture of the cyclic acetals obtained is reacted in the presence of 5 g of crosslinked sulfonated polystyrene resin (Dowex 50; grain size 0.59 mm) and 5 g of Raney nickel at 85 ° C. with 20 g of water and at a pressure of 70.3 kg / cm2 hydrogenated for one hour with hydrogen. Gas chromatographic analysis shows that the linear isomer 35 undergoes 86% conversion and gives 0.4 mol% tetrahydrofuran and 99.6 mol% 1,4-butanediol. The branched isomer undergoes only 42% conversion.

With an identical reaction, except that the temperature is 130 ° C., the linear isomer undergoes 99.2% conversion and gives 52 mol% tetrahydrofuran and 48 mol% 1,4-butanediol.

Processes 8 to 10 The prehydrogenation and hydrolysis-hydrogenation described in process 45 was repeated, except that 40 g of a mixture of the acetal aldehydes described in the following table are used.

Response times

Process Compounds Hydrogenation Temp. Hydrolysis Temp. Conversion Mol '/ c Yields

Hydrogenation of the linear 1,4-

Isomer THF butanediol

8 2- (3'-propanal) -5-methyl- 50 min. 60 ° C 62 min. 85 ° C 88 0.6 98 1,3-dioxane 88%

2- (2'-propanal) -5-methyl-1,3-dioxane 12%

9 2- (3'-propanal) -4-methyl- 60 min. 62 ° C 75 min. 90 ° C 96 3.0 96 1,3-dioxane 84%

2- (2'-propanol) -4-methyl-1,3-dioxane 16%

10 2- (3'-propanal) -4,4,6- 50 min. 60 ° C 60 min. 85 ° C 97 0.5 99

trimethyl-1,3-dioxane 86%

2- (2'-propanal) -4,4,6-trimethyl-1,3-dioxane 14%

13

624 374

Procedure 11

100 g of 2- (3'-propanal) -5,5-dimethyl-l, 3-dioxane 84% and 2- (2'-propanal) -5,5-dimethyl-1,3-dioxane 16% are in the presence of 5 g of Raney nickel at 80 ° C and a pressure of 70.3 kg / cm2 treated with hydrogen. The reaction is complete after 5 60 minutes. The reaction product is then filtered off and in the presence of 5 g of a crosslinked, sulfonated polystyrene (Dowex 50) and 5 g of Raney nickel for two hours at 80 ° C. with 50 g of water and at a pressure of 70.3 kg / cm 2 with hydrogen implemented. An 80% conversion is achieved and the product obtained contains 0.9 mol% tetrahydrofuran and 98 mol% 1,4-butanediol.

The polyols obtained can be used for any purpose for which polyols are suitable, such as reaction with isocyanates to urethanes and polyurethanes, with acids to esters and polyesters, etc.

s

Claims (13)

624 374 PATENT CLAIMS 1. A process for the preparation of liquid acetals with a solubility of less than 10 percent by weight in 25 ° C warm water, characterized in that a mono-alcohol and / or a diol with at least 4 carbon atoms and with diols having a maximum number of 3 carbon atoms between the Diolhydroxyl groups, at a temperature in the range of 0 to 100 ° C in the presence of an acidic catalyst with at least a stoichiometrically equivalent amount of an aldehyde and / or a dialdehyde is reacted, whereby a two-phase, aqueous-organic, liquid product is formed, in which the acetal is in the organic phase. 2. The method according to claim 1, characterized in that one equivalent of alcohol is reacted with 1 to 1.5 equivalents of aldehyde. 3. The method according to claim 1, characterized in that the mono-alcohol used has a maximum of 20 carbon atoms in a straight or branched chain. 4. The method according to claim 3, characterized in that the diol or mono-alcohol used 2-methyl-l, 3-propanediol, 1,3-butanediol, 2,4-pentanediol, 2,2-dimethyl-l , 3-propanediol, 2-ethyl-l, 3-pro-pandiol, 2-methyl-2,4-pentanediol, 1,3-pentanediol, 2,4-hexanediol, 1,3-hexanediol, 2,2 -Diethyl-l, 3-propanediol, 1,3-heptanediol, 2,4- or 3,5-heptanediol, 2,3-butanediol, 2,3-dimethyl-2,3-butanediol, 2,3- Diethyl-2,3-butanediol, butyl, amyl, hexyl, heptyl, octyl, decyl, lauryl, myristyl, stearyl, cro-tyl, benzyl, cinnamyl, isobutyl , Isoamyl alcohol, 4-methyl-1-pentanol, 3-methyl-1-pentanol, 2,3-dimethyl-1-pentanol, 2-ethyl-1-hexanol or 2-phenyl-1-ethanol is or that mixtures of the alcohols mentioned are used. 5. The method according to claim 1, characterized in that alcohols are used as the mono-alcohol which, in addition to the hydroxyl group, contain heteroatoms, such as oxygen or sulfur, for example alcohols which contain one or more of the following substituents: alkoxy (Ci-C4) , Aryloxy such as phenoxy, naphthoxy, halogen, —N02, -SH. 6. The method according to claim 5, characterized in that the monoalcohol used is 4-chloro-l-butanol, 4-bromo-l-butanol, 3,4-dichloro- or 5-chloro-l-pentanol, 4-iodo-l-butanol, 2-ethoxy-l-ethanol, 3-methoxy-l-propanol, 4-methoxy -l-butanol, 2-butoxy-l-ethanol, 3-butylthio-l-propanol, 4-methylthio-l-butanol, 3-acetoxy-l-propanol, 4-acetoxy-l-butanol, 3-nitro-l -butanol, furfuryl alcohol, 3-phenoxy-l-propanol, 2-phenoxy-l-ethanol, 2-naphthoxy-l-ethanol, 4-nitro-l-butanol, 2- (p-nitrophenoxy) -l-ethanol or p -Chlorbenzylalkohol, or that mixtures of the alcohols mentioned are used. 7. The method according to claim 1, characterized in that the aldehyde and / or dialdehyde used is an optionally substituted saturated or unsaturated aliphatic, cycloaliphatic or aromatic aldehyde, the z. B. chlorine, bromine, Q-Qo-alkyl, aryl such as phenyl and naphthyl, carbalkoxy having 1 to 10 carbon atoms in the alkoxy group or Cj-CktAlkoxy contains as substituents, the substituents being selected from those that formed Do not solubilize the organic phase and do not interfere with the alcohol-aldehyde reaction. 8. The method according to claim 1, characterized in that the aldehyde and / or dialdehyde used formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, isobutyraldehyde, isovaleraldehyde, caproalde-hyd, heptaldehyde, octaldehyde, caprinaldehyde, stearaldehyde, acrolein, crotonaldehyde, crotonaldehyde Furfural, glyoxal, phenylpropargylaldehyde, 2-penten-l-al, 2-methyl-2-penten-1-al, cinnamaldehyde, p-chlorobenzaldehyde, p-bromobenzaldehyde, m-nitrobenzaldehyde, p-fluorobenzaldehyde, p-methoxybenzaldehyde, o-methoxybenzaldehyde, naphthaldehyde, y-acetoxybu-tyraldehyde, diethyl-a-formylsuccinate, formylcyclopentane, trimethylacetaldehyde, ethylglyoxylate, chloroacetaldehyde, 3-bromopropionaldehyde, terephthalaldehyde or ethyl-p-formaldehyde is used or the mixtures mentioned are used or the mixtures called albenzoate. 9. The method according to claim 1 for the production of acetals with six-membered rings, that is, 1,3-dioxanes, from 1,3-diols and aldehydes. 10. The method according to claim 9, characterized in that 40-acrolein with 2-methyl-1,3-propanediol to 2-Vi nyl-5-methyl-l, 3-dioxane according to the reaction scheme 30th 35 cii = ch, CH. CH_ — CHCHO + HO-CH “—CH-CH-Ofî -> + ii2o CH- is implemented. 11. Liquid acetals, produced by the process according to claim 1. 12. Use of those liquid acetals according to Pa 55 claim 11, which have an olefinic double bond, in hydroformylation reactions, i.e. in reactions of the acetals mentioned with H2 and CO to corresponding acetal aldehydes.