DE1442692C - Use of addition compounds composed of 3 moles of formic acid and one mole of a tertiary organic base for the reduction of alpha-halogenated carbonyl compounds, nitro compounds or sulfur dioxide - Google Patents

Description

3 4

are consumed when there is enough free formic acid ternary mixture based on the addition compounds

is present or is supplied; they therefore need trimethylamine, triethylamine and pyridine (Mi-

in the reaction mixture also not in one of the ratio 1: 1: 1), the latter being preferred

reducing substance equivalent ratio. . .

to be present. "5 The advantage of using these mixtures is

The addition to be used according to the invention is often also in the suppression of side reactions

Connections are made according to their own functions, such as B. the elimination of hydrogen halide

Patent application produced by 1 mol in the reduction of chlorinated aldehydes and ketones, the

the tertiary organic base as such or in the suppression of acyloin condensations and

State of origin with at least 2 moles of ant resinification.

acid or formic acid in the state of formation, it can also be advantageous in the inventive

optionally in an inert medium for the reaction, use of the addition compounds mentioned

brings, excess formic acid and water distil- fertilize small amounts of certain metals and / or

relatively removed and add the addition product 'given' metal compounds; z. B. be ali-

if, after purification by distillation, with volatile and aromatic nitro and polynitro compounds

reduced pressure, isolated. ■ · ...; bonds without the addition of such metal catalysts

For example, the addition compound only boils slowly reduced - so wildly with sole

3 moles of formic acid and 1 mole of trimethylamine when using the addition products according to the invention

a pressure of 15 mm / Hg const. at 87 ° C. p-nitrobenzaldehyde selective only to p-nitrobenzyl

As further examples of tertiary organic bases, reduced from 20 alcohol, in the presence of palladium or

where the addition compounds of platinum and copper (I) chloride mentioned, the reduction takes place

3 moles of formic acid and 1 mole of tertiary organic, on the other hand, quickly fall, and in good yield the

Base which can be obtained are the following N-formyl compounds of the amines formed or

Examples of bonds: Obtain polyamines.

I. Aliphatic substituted tert. Amines and poly- ²⁵ As such, metals and / or metal compounds

amines, such as triethylamine, methyldiethylamine, Di- ^seie "mentioned for example: copper chloride, but

methylethylamine, diethyl-n-propylamine, dirne ^au f ^h copper (II) salts which quickly form copper (I) formates

thylpropylamine, dimethylbutylamine, N-methyl- are reduced in very active systems, such as

dibutylamine, tri-n-butylamine, dimethylstearyl- "f · ^B · ^be , ^J. trimethylamine / formic acid, already after

amine, permethylated ethylenediamine, permethy- ³ ° the reduction to finely divided metalh-

lated diethylenetriamine and triethylenetetramine,!, chem copper takes place It is essential that also in this

furthermore ester group, ether group and nitrile ^{phase dl} f catalytic «? Effectiveness of the additive

group-containing permethylated aliphatic ^{ba e} ° ^Weib £ * ^{benso WK} ; ^htl | , f " ^{d precious metal} £> ™ ^e

imii, »„ n ^ D _n i, ™ _m in / ■■■■■ ·. ■ r palladium, palladium oxide, palladium on charcoal,

/ \ 111111c uiiu r υιγαπιιηρ. . _ ^ _{J <T} *. .. ._.... ...... _T ~ ..

35 platinum, rhodium and indium as well as common hydne-

II. Aliphatic-cycloaliphatic substituted amines approximately catalysts, such as Raney nickel. The cataly-

and polyamines, such as dimethylcyclohexylamine, tables influencing the decomposition of the said Addi-

Diethylcyclohexylamine, permethylated and hydrogenated compounds through the addition of metals and

third p-phenylenediamine. :. Metal salts take the example of copper (I) -: chloridTZu-

III. AraHphatically-substituted amines, such as dimethyl- 40 rate described. While z. B. the activated

benzylamine, diethylbenzylamine, di-n-propylben- formic acid in the addition compound of 1 MoIe-

zylamine. kül trimethylamine and 3 molecules of formic acid in

", _TI,. . _. '.,' ■. '. . ,. Absence of reducible compounds

• 5 \ 7 ° u ^y ? ^S ul * ^Se \ r w ^e u ^P , ^yn \ ^C XT ⁰ L ¹ T ¹ ? ' 140 to 170 ° C very quickly and almost quantitatively in carbon

N-Methylmorphohn, N-Methy! Piperidin, N, N- _{45 len} oxide and water disintegrates, a catalytic urges

pimethylpiperazine, Endoathylen-piFeranzi and _{addition of the} copper salt, the carbon dioxide and water

bicychic amidines as z. B by investment _{büdun very gtark Zlirück and there is a cerium} f _a ll of

tion of acrylonitrile on pyrrolidone and post- _activated formic acid in hydrogen and CO ₃

following hydrogenation and cyclization _s tatt available undzwar already at a temperature of 125 to

- "- ·. ■■ '■. · ..... · 50 145 ° C. The same effects are obtained with palladium,

There are also numerous other oiganische platinum and known hydrogenation catalysts, see above

tertiary bases with molecular weights <300, those with amei- that from the addition compounds mentioned

sens acid, the addition compounds mentioned form hydrogen for hydrogenation of the

and can be used according to the invention. Adducts of the most diverse connections are sufficiently activated.

of organic tertiary bases with a molecular weight of 55. In general, however, there is no need for the reduction

> 300 and formic acid have a substantial tion of all carbonyl compounds that have a high

have higher boiling points than those mentioned erfindungsge- polarization of the carbonyl group, z. B.

moderate addition compounds and decompose when generated by α-halogen substituents, and how

the distillation. · .- ■. ·· they z. B. is clearly present in chloral, every cat-

The addition compounds according to the invention are lytic additions of the abovementioned metal salts to the

• In general, also good solvents for the reducing agents according to the invention, since here the

reducing compounds. However, it can get going extremely quickly and for reduction

further increase in solubility of the to be reduced apparently not due to the occurrence of elemental

Substances be advantageous, binary or ternary Mi- hydrogen is bonded. In this case, there is a good

mixtures of the addition compounds according to the invention without side reactions such as chloroform cleavage

gen to use, e.g. B. obtained the mixture of the addition. Tung trichloroethyl alcohol. Likewise leaves

compounds based on trimethylamine and N-methyl-. for example, the Schvvefeldioxyd in the invented

morpholine (mixing ratio 1: 0.5) or the reducing agent according to the invention without any catalytic

5 6

additional tables playfully in crystallized, elementary columns; after 1 hour there are about 40 liters of CO ₂ , after reducing sulfur. 2 hours already 64 liters of CO _{2 released} . To

It was already mentioned that reduction under a further 4 hours are about 95 liters of gas escaped, using mixtures of Ameisensäuie and and the Gasabspajtung has at an internal Tempe tertiary organic base, optionally with the addition of 5 temperature 105-110 ⁰ C in its speed by by Raney Nickel, belong to the state of the art. about the tenth part decreased. From this point on, the use of the defined point according to the invention increases the splitting off of carbon oxides. The addition compounds of 3 moles of formic acid and the remaining reduction takes place in the distillative removal of 1 mole of a tertiary organic base, but offers the trichloroethanol formed. To this end, the considerable advantages over the prior art: io reflux condenser of the apparatus is replaced by a 30 cm long column, and a mixture is distilled under reduced pressure (300 to 400 mm) in the reduction of carbonyl compounds which consists of only two phases with the formates of tertiary nitrogen bases. The lower phase consists of trichloro yields up to about 55% of theory. In contrast, ethanol, which contains about 23% formic acid, which is kept in the reduction of chloral hydrate below 15, the upper phase of water with about 15 to 21% of the addition method according ^{to the invention.} sensic acid and small amounts of dissolved trichloride bond from 3 mol formic acid and 1 mol triethyl alcohol. The separated aqueous methylamine layers, a yield of 86% of theory, are continuously added to the reduction batch again to give trichloroethanol. If one tries in accordance with that and uses water and formic acid as dragging prior art chloral hydrate, chloral alcoholate 20 medium for trichloroethanol. Distillation is carried out until chloral or anhydrous chloral no longer separates in the distillate as described below. Then comparative example 1 is reduced, no amounts of trichloroethanol that can be distilled towards the end in a water jet vacuum are obtained, but more until the trichloroethyl alcohol in the distillate does not exceed 90% of the theoretically possible chlorine yield. Overall, form is obtained. In contrast, 25 parts by weight of trichloroethanol are obtained in accordance with Examples 2 and 3 also using the formic acid content of about 23% per se. Yield of non-preferred addition compound from 3 moles of crude trichloroethanol: 635 parts by weight = 86% of the formic acid and 1 mole of triethylamine and also below theory. The crude Trichloi ethanol is obtained by adding a small amount of Raney nickel, a yield of 80% and amounts of trimethylamine salts and small amounts more theoretically of trichloroethanol. 3 ° trichloroethyl formate by saponification and distillation

In addition, the inventive use of the addition compounds purified with dilute aqueous sulfuric acid, optionally un-bp of the pure and formic acid-free trichloride, preferred addition of palladium, platinum and / or ethanol 57 to 58 ° C at 15 mm. or copper salts a new method of reduction
of nitro compounds and sulfur dioxide. 35 Comparative example 1

In particular, the reduction according to the invention of According to the prior art (Chem.

Sulfur dioxide enables an elegant cleaning of abstracts, 50 [1956], column 5544 g, lines 3 to 7) who-exhaust gases, those of the 5 g Raney per mole of substance to be reduced, superior in terms of environmental protection Meaning is. In this latter case, nickel, 5 moles of triethylamine and 5 moles of formic acid There are additional advantages that 40 to pure in 85 percent by weight aqueous solution directly Fine powder, crystallized and excellent production used. . . ■ '

filterable elemental sulfur is obtained, the mixture described above is added

standing water practically does not interfere with the reduction

and the reducing power of the said addi-?> } ^ o £ h ora hydrate

tion compounds also in dilute aqueous solution 45, ^b }} ™ ° ^l chloral alcoholate and is retained. In addition, nitrous gases are reduced at the same time c) 1 mol of anhydrous chloral and removed from the exhaust gases. and heated to the boil. After just 20 minutes

. . the internal temperature of the reaction mixture decreases from

Example 1 100 to 8O ⁰ C, and can not be increased again.

In a three-necked flask with a thermo 5 ° After 3 hours, 2 moles of the meter, stirrer, reflux condenser and dropping funnel formic acid (85 percent by weight) are added and the reflux condenser is connected to a gas and the reaction mixture for a further 7 hours connected to the return clock, 788 parts by weight of the river are heated. In this second reaction phase of the liquid addition product of 3 molecules of amei, the boiling temperature of the refluxing sensic acid and 1 molecule of trimethylamine (So. 87 ° / 15mm) 55 mixture is only 75 ° C. The drop in Siedetemvorgelegt and is 827 parts by weight of chloral hydrate temperature after a short reaction time can already be solved eruntei stirring at about 70 ⁰ C. It increases the know that not the reducing approach, the reduction of the aldehyde but the saponification ambient temperature takes place under the reaction conditions at a internal temperature of about 130 to 140 ⁰ C until a kräf- of Chlorais to chloroform. Demented reflux sets in. If after about 25 minutes 60 speaking one does not get strong CO ₂ evolution even with distillative work-up, then one adds one of the 3 test approaches:.

the approach 25 ecm concentrated formic acid to.

whereupon the COo development starts immediately. ^{in the v} " ^s " ^ch . ^a ),. , ',,

According to the amount of gas indicated by the gas meter,. ⁹⁴ % of the theoretical yield of chloroform, mainly from CO ₂ and only a small amount 65 in experiment b)

CO amounts, fresh 96% of the theoretical yield of chloroform is added dropwise to the batch,

concentrated formic acid. At the start of the reduction in experiment c), about 1 liter of CO ₂ per minute is removed from 91% of the theoretical yield of chloroform.

The formation of Trichloräthanoi can be with this a distillation analysis cannot be used to demonstrate work-up.

B e i s ρ i e 1 2

The procedure is as in Example 1, but using the addition product of 1 mole of triethylamine and 3 moles of anhydrous formic acid with a bp anhydrous formic acid. 827 parts by weight of chloral hydrate (= 5 moles) are mixed with 956 parts by weight of the addition product of 1 mole of triethylamine and 3 moles of anhydrous formic acid (= 4 moles) in accordance with the example and 125 parts by weight of Raney nickel are added in accordance with the quantitative designation of the above comparative example. The reaction is then carried out as in Example 1, in which the formic acid consumed ( _{monitored by CO 2} measurement) is continuously replaced by adding the equivalent amount (= a total of 5 mol).

In the work-up by distillation, the following are obtained:

80% of the theoretical yield of trichloroethanol, 12% of the theoretical yield of chloroform.

For s ρ ie I 3

If one proceeds exactly as in Example 1, only the addition product of trimethylamine and Formic acid by the mixture of triethylamine and formic acid and omits the addition of Raney nickel, the saponification reaction continues to be suppressed and less than 8% of the theoretical is obtained possible yield of chloroform:

As in Example 1, 800 parts by weight of the adduct of 3 molecules of formic acid and 1 molecule of triethylamine (boiling point 97 ° / 18 mm) are used to reduce 900 parts by weight of chloral alcoholate. Before the start of the reduction, 300 parts by weight of formic acid are added and, with only moderate reduction, ethyl formate formed is removed via a column. This is then reduced with further addition of formic acid, as described in Example 1, the rate of CO ₂ elimination taking place approximately as in Example 1. After working up the distillates according to Examples 1 and 2 and after purifying them, about
Sdp. 57 to 58715 mm.

82 ° / ₀ to trichloroethanol,

B e i s ρ i el 4

62 parts by weight of nitrobenzene, 197 parts by weight of the addition product of 3 molecules of formic acid,

ίο 2 parts by weight of copper (I) chloride and 6 parts by weight Palladium on Α carbon (5%) graze reduced at 130 ° C. You reduce until the gas meter has a Displays an amount of 114 liters and removes water together with formic acid while adding it at the same time this year formic acid during the distillation. The trimethylamine-formic acid addition product is then used distilled off and pure formanilide from by distillation in a water jet vacuum Bp. 163 ° C. at 18 mm in a yield of 55 parts by weight.

Example5

The following example shows a large number of Reducing agents when carrying out short tests that formic acid by simple salt formation or already so strongly activated by the formation of adducts of further formic acid molecules with formic acid salts is that even sulfur dioxide is easily reduced to elemental sulfur:

Comparative experiment A:

No matter how long sulfur dioxide is introduced into boiling formic acid, none is obtained elemental sulfur.

Trial series B:

If, on the other hand, SO _{2 is introduced} into the liquid mixtures or liquid addition compounds listed in the table at 95 to 108 °, sulfur separation in the form of very fine crystals occurs quickly, which can be filtered off extremely well. Even the use of the weak base pyridine allows an almost quantitative reduction to elemental sulfur, although larger amounts of water do not interfere (see experiment C).

base

Mole

acid

speed
the S-separation

Trimethylamine

Triethylamine

Dimethylcyclohexylamine ..

Dimethylbenzylamine.

Pyridine

N-methylmorpholine ....

Endoethylene piperazine

permethyl. Ethylenediamine

bicyclic amidine

CH ₂ - CH

CH ₂

2,3,4,5,6
2,3,4,5,6
1,2,3,4

0.5; l, 2.3,

0.3; 0.5-3

2.3

3,4,5,6

3-8

2-6

very quickly

quickly

quickly

slack
very quickly
very quickly
very quickly

quickly
very quickly

309 613/138

9 10

Experiment C introduces a total of 320 parts by weight of sulfur dioxide

and continuously replaces used formic acid.

In a mixture of 158 parts by weight of pyridine, small amounts of sulfur dioxide escape, since 276 parts by weight of formic acid and 600 parts by weight share the residence time in the reducing medium kept small, water is slowly 5 at 100 ° C sulfur dioxide. One receives in an almost quantitative yield an introduced CO ₂ development starts immediately, and sulfur which can be filtered off is excellent. Yield crystallized sulfur separates out quickly. One 148 parts by weight. . .

icnu ■■■ ·! ·, ■ ■

Claims (2)

1 2 The reduction of azines to hydra patent claims: zinen using triethylamine and formic acid with the addition of Raney nickel is also known (Chem. 1. Use of addition compounds from Abstracts, 50 [1956], pp. 5544 e to 5545 a). 3 moles of formic acid and one mole of a tertiary 5 According to our own earlier application P12 33 398.1-09 organic base, if necessary with the addition of cf. German patent specification 1 233 398, addi- Palladium, platinum and / or copper salts for reaction compounds from 3 mol of formic acid and 1 mol Induction of a-halogenated carbonyl compounds of a tertiary organic base, if 1 mol of the gen, nitro compounds or sulfur dioxide to tertiary organic base as such or im a-halogenated alcohols, to amino compounds io state of formation with at least 3 moles of go or to elemental sulfur. acid or formic acid as it is formed 2. Use of addition compounds composed of 3 moles of formic acid and 1 mole of tertiary organic Claim 1, characterized in that at. nischer base-existing addition product converts, the reduction of formic acid to the extent that this addition compounds can be used continuously the reduction batch, if necessary after purification by distillation will. . reduced! Isolate pressure as defined connections. 3. Use of the addition compound from It has now been found that it is particularly advantageous Mole of formic acid and one mole of trimethyl is liable if you take these addition compounds off amine as a reducing agent, according to claims 1 3 moles of formic acid and 1 mole of a tertiary orga- and 2. 20 niche base, optionally with the addition of palladium 4. Use of ternary mixtures of dium, platinum and / or copper salts for reduction Trimethylamine, triethylamine and pyridine amei of a-halogenated carbonyl compounds, nitroversenic acid additive compounds as reduction compounds or sulfur dioxide to a-halogenated agent, according to claims 1 and 2. alcohols, to amino compounds or ^ u elementaas rem sulfur used. . The reduction is at normal or err high pressure at temperatures between '40 and It is known that in the Leuckart-Wallach reaction 180 ° C., preferably between 65 and 165 ° C., occurs Formic acid according to the following equation as performed. Reducing agent is effective: 30 Can be used to increase the rate of reaction hydrogenation catalysts, e.g. B. palladium or R ² \ / ^ ³ platinum and / or copper (I) salts of inorganic or , NH + O = C + HCOOH— ^ "organic acids in catalytic amounts. / / \ turn. 35 In general, the reduction is n 2 R4 according to the use of the addition compounds \ / '3 moles of formic acid and 1 mole of a tertiary organic / N - CH. + CO ₂ + H ₂ O nic base, as described below, through R ¹ R ³ leads: 40 The compound to be reduced is R ¹ to R ⁴ = H or hydrocarbon radicals given addition compound if with the use of solvents, such as According to this amine alkylation method, for example, 1,4-dioxane, dimethylformamide and z. B. ammonia, primary and secondary amines dissolved by formamide. When warming to 80 to 145 ° C with formaldehyde and formic acid, the reduction begins. B. methylate with a gas to tertiary amines, where one measured for clock released CO _a amount is each introduced methyl group is only a little more than a measure of the progress of the reduction. One can use the equimolar amount of formaldehyde needed. work without pressure as well as with increased pressure. It is also known to use a mixture of ant-reducing gases such. B. SO ₂ can even be used in Versäure and a tertiary amine as a reducing agent 50 thinning at 80 to 105 ⁰ C in the reducing agent. So n-propyl- and n-butyl-quino- were passed and are reduced in the process. You can reduce linium bromite with a mixture of 1 Mo} triethyl without excess formic acid, usually amine and 4 moles of formic acid to the corresponding, however, it is advisable to work in the acidic area, reducing tetrahydroquinoline compounds, whereby one per mole of the to reducing substance mol of starting product to be reduced an amount of gated formic acid corresponding to 8 mol 55 about 0.5 to 5 mol, preferably about 2.5 mol of concentrated formic acid. Corresponding to the mixture was used (Chem. Abstracts, 51 [1957]) , by the amount of CO _a released, measured Ver-S. 1958 e to g). Formic acid consumption, is preferred to the Likewise, among other things, 2,2,4-trimethyl-reduction approach was continuously new formic acid 1,2-dihydroquinoline to the corresponding 1,2,3,4-Te-60 maintenance of the excess used to tetrahydroquinoline using triethylamine and guided, but this measure is not mandatory, Formic acid in a molar ratio of 1: 4.6 reduced if the approach from the beginning at least the '(Chem. Abstracts, 59 [1963], p. 13 947 d, e). stoichiometrically necessary amount of formic acid ent. The right is from German patent specification 933 337. Reduction of aldehydes and ketones with ants 65 It is advantageous, however, according to the versoic acid in the presence of 'tertiary nitrogen bases in need of supplying fresh formic acid, since the aqueous Medium known, the yield of all mentioned addition compounds of formic acid thing is only 30 to 40% of theory. act catalytically and not during the reaction