NO158433B - AXIAL PUMP PUMP DRIVE MECHANISM. - Google Patents

Abstract

1. Barrel mechanism comprising, inside a casing (1), a drive member (4) mounted pivotally on at least one fixed bearing (31, 32) defining an axis (10) about which the drive member (4) is driven rotationally, a barrel (5) rotationally fixed and mounted pivotally on the drive member (4) about an axis (50) inclined relative to the axis of rotation (10) and convergent with the latter, a first axial thrust bearing (52) interposed between the barrel (5) and an oblique plate (40) disposed on the drive member (4) perpendicularly to the axis (50) of the barrel, and a second axial thrust bearing (44) interposed between a straight plate (45) disposed on the drive member (4) perpendicularly to the axis of rotation (10) and a fixed plate (33) which, through the medium of the two axial thrust bearings (44, 52), takes up the forces parallel to the axis of rotation (10) which are applied to the barrel (5), characterised by the fact that the fixed plate (33) is disposed at one end of a central column forming a spindle (3) defining the pivot axis of the drive member (4), while at the other end of the said central column is supported a means (6) for the elastic clamping of the drive member (4) against the fixed plate (33), the cassing (1) being provided with detechable means for fastening the spindle (3), the latter forming with the drive member (4) and the barrel (5) a compact assembly adapted to be installed in and removed from the interior of the casing (1) as a unit.

Description

Process for the production of α,α'-tetra-alkyl-substituted (cyanomethoxy)-acetic acids and derivatives thereof.

The invention relates to the production of «.«'-tetraalkyl-substituted (cyanomethoxy)-acetic acids and derivatives thereof, e.g. the corresponding diglycolimides and diglycolic acids. α,α'-tetraalkyl-substituted (cyanomethoxy)-acetic acids and the corresponding diglycolic acids (oxy-2,2'-diacetic acids) form difficult-to-saponify esters, and until now only difficult-to-access components for polyesters and polyamides. The «.«'-tetraalkyl substituted diglycolimides are important components for formaldehyde resins. The α-oxycarboxylic acids and esters thereof which can be prepared from the α,α-tetraalkyl-substituted (cyanomethoxy)-acetic acids, resp. from their derivatives, finally constitute valuable raw materials for the production of methacrylic acid, its higher homologues and its esters.

The invention relates to a process for the production of «.«'-tetraalkyl-substituted (cyanomethoxy)-acetic acids with the general formula:

where R1; R 2 , R 3 , R 4 mean methyl or ethyl ester, and their derivatives, which can be split into α-oxycarboxylic acids by ether cleavage or hydrolysis. The characteristic feature of the method is that 4-oximino-2,2,5,5-tetraalkyl-substituted 3-oxotetrahydrofurans with the general formula:

treated at temperatures of 40-200°C with water, alcohol or an organic solvent inert to carboxyl and/or carboxylic acid nitrile groups with a boiling point above 75°C during ring cleavage between C(3) and C(4), and the formed " .«'-tetrasubstituted jScyanomethoxy)-acetic acids are optionally transferred to the corresponding diglycolimides or diglycolic acids by further treatment with the aforementioned reaction medium, optionally in the presence of esterification or transesterification catalysts or in the presence of anhydride-forming compounds.

4-oximino-2,2,5,5-tetraalkyl-substituted 3-oxotetrahydrofurans occur by

reaction of «,α'-tetraalkyl-substituted 3-oxotetrahydrofurans with nitric acid, resp. its derivatives.

As agents that act solubilizing on the oxidation product, which has a; ring cleavage ability, and which are inert towards the formed carboxyl and/or nitrile groups, mention should be made of organic solvents with a boiling point above 75°C, such as aromatic or aliphatic hydrocarbons, e.g. benzene, toluene, xylene, gasoline, higher ketones, e.g. methyl ethyl ketone, carboxylic acid amides, e.g. dimethylformamide, ","-secondary dicarboxylic acid amide isopropyl ether, or pyridine and homologues.

Substances which have a dissolving effect on the oxidation product, and which have a ring-cleaving ability and which can react with the formed carboxyl and/or nitrile groups, are primarily substances which during saponification or esterification can react with the carboxyl and/or carboxylic acid nitrile groups, such as water and monohydric or polyhydric alcohols with a saturated or unsaturated hydrocarbon residue which may be aliphatic or aromatic.

Appropriately, the reaction is accelerated. This can be done by heating to temperatures of 40-200°C, or by using saponification, esterification or transesterification catalysts or anhydride-forming compounds. Of course, both methods can be combined.

As saponification, esterification or transesterification catalysts, one can use substances that act basic, neutral or acidic, such as alkali or alkaline earth hydroxides, -oxides, -alcoholates, alkylesters of 'titanic acid, inorganic, Lewis and organic acids, e.g. mineral acids in small quantities, such as H2SO., (the use of H2SP4 of higher concentration is more closely described in Norwegian patent no. 113 333, H3P04, HC1, their correspondingly active organic compounds, e.g. paratoluene-sulfonic acid, sulfonated ion-exchange resins, acid-reactive compounds, such as FeCl3, TiCl4, SnCl4, BF3, ZnCl2, A1C13.As anhydride-forming compounds, acid anhydrides or acid chlorides can be used in the presence of HCl-binding compounds, e.g. pyridine.

When you use acid-acting esterification catalysts, you should only use them if the reaction medium is alcohol-free, i.e. you should use these acid-acting catalysts only when the reaction medium is an organic solvent that is inert to carboxyl and/or nitrile groups, or an alcohol, but not water. If aqueous acids are used, no ring splitting occurs between the C1 and C4 carbons, but "^'-diketotetrahydrofurans are formed.

The nature and quantity of the catalysts used depends on whether the α,α-tetrasubstituted (cyanomethoxy)-acetic acid is to be isolated or whether it is to be transferred to its derivatives such as diglycolimide or diglycolic acid, by reaction of carboxylic and /or the nitrile group in the reaction medium itself. If the (cyanomethoxy)-acetic acid is to be isolated, it is expedient to work so that the oxidation product of the corresponding 2,2,5,5-tetraalkyl-substituted 3-oxotetrahydrofurans is distributed in an inert solvent, e.g. toluene, or in solvents reactive towards carboxyl and/or nitrile groups, e.g. alcohol, water and that alkali hydroxide is used as a catalyst. Appropriately used per mol oxime 1 mol alkali hydroxide. In addition to acting as a catalyst, the alkali hydroxide also serves as a stabilizer for the α,α'-tetrasubstituted (cyanomethoxy)acetic acid which can be isolated as the alkali salt. Here it should be noted that the site should be isolated as soon as possible after ring splitting has been completed. If the salt is allowed to remain in the reaction medium after the salt has been formed, a corresponding diglycolic acid is formed by hydrolysis of the nitrile group. The time for the completed ring cleavage can be ascertained by the fact that ammonia begins to evolve. When water is used as solvent, the end of the reaction can be ascertained by the color changing from deep red to yellow,

When one does not use, or only uses a small amount of. catalyst, the «.«'-tetrasubstituted (eyano-methoxyX-acetic acid is converted to its diglycolimide:

It should be mentioned here that the solvent, which is capable of cleaving the ring, can act as a reaction regulator. If one f, e.g. for ring cleavage an alcohol is used, with the general formula ROH (R = alkyl), this alcohol with the carboxyl group in (.cyanomethoxy)-acetic acid can form the corresponding ester, which then during the pm-<1 >formation leads to an N-substituted d > glycoimide with the formula: Similarly, by using an anhydride-forming addition, N-substituted diglycomides with the general formula can be obtained;'' <

if larger quantities of the catalyst (e.g. KOH) are used, or if the formed (cyanomethoxy)-acetic acid is allowed to remain in the reaction medium without isolating it or if previously isolated (cyanomethoxy)-acetic acid is introduced into the reaction medium, undergoes initial opening of the nitrile group and the corresponding diglycolic acid is formed, resp. its salts.

Regarding the use of heat as a reaction-accelerating agent, it can generally be said that in the absence of catalysts it is already sufficient to use temperatures of 9.0°C to achieve satisfactory results. turnover rates. If you use catalysts, these speeds are already reached at temperatures of approx. 50°C.

The production of a-oximation products ay 2v2i5,,5-tetraAlalkylsubstituted 3,-qksptetrahydrfurans can take place in a known manner, by addition ay 2- mol; ketone to 1 mpL of acetylene, conversion of the formed tetraalkylsubsMuated hexinediol in the presence of soluble mercury oil (li.) catalysts to water-insoluble 2,2,5,5-tetraalkyl-substituted 3-oxotetrahydrofuran, and finally by the α-oximation with salp -tertacid, its esters, chloride or anhydrides.

The production of the a-oximation product and the further reaction according to the invention can also take place in the reaction vessel itself (compare example).

The course of the process in accordance with the formula is reminiscent of the well-known "Beckman reaction" which leads from keto-oximes to substituted primary carboxylic acid amides. However, in the practical implementation of the "Beckman rearrangement" <p>g of the method according to the invention, one encounters significant differences in the two reactions. According to modern and recognized considerations

is needed to trigger the "Beckmanian rearrangement" strongly acidic resp. acid-forming substances, such as H2SO„ S03, P905, SOCl2,

PCI, .

Under the influence of these acids, cations are formed from the oximes and, after splitting off water, the "Beckman rearrangement" is completed. With the new method, on the other hand, not only can the use of acids be dispensed with, but a significant reaction acceleration and high yields of the desired reaction products have also been achieved with strong alkalis in excess.

The new method is limited to the oxidation products of 2,2,5,5-tetraalkyl-substituted 3-oxotetrahydrofurans obtained as yellow crystals as starting compounds. If one subjects the analogous α-oximerized tri-, di-, mono-alkyl-substituted or not at all substituted 3-oxotetrahydrofurans to conditions under which the new method proceeds without difficulty, one does not obtain, or with not noticeable yields , the corresponding (cyanomethoxy)-acetic acids and their derivatives. In the new procedure must. it is therefore assumed that the special steric conditions of α-oxotetrahydrofurans are chemically an essential prerequisite and that. they favor the relocation from them. fully substituted 5-membered oxygen compounds in the obviously more relaxed, resp. 6-joint compounds. Also. here lies a significant difference with the well-known "Beckman rearrangement", in which a rearrangement of the 6-membered cyclohexane monooxime to the 7-membered caprolactam takes place technically.

The (cyanomethoxy)-acetic acids produced according to the method, resp. their derivatives can, by ether cleavage with concentrated acids, be transferred to correspondingly substituted '-oxycarboxylic acids.

Example 1.

0.3 mol of 4-isonitroso-2,2,5,5-tetramethyl-3-oxotetrahydrofuran is transferred to the corresponding potassium salt of the oxime with an equimolar amount of 25% KOH at low temperature. The strong red, aqueous solution of the oxime salt is heated to the boiling point under reflux. After 10-15 minutes, a complete rearrangement can be observed by a sharp color change of the reaction solution from red to faint yellow. It cools right away. The reaction solution is then shaken with ether to remove the impurities, and an equimolar amount of hydrochloric acid is slowly added to the aqueous layer while cooling. To isolate the carboxylic acid, shake once more with ether, and the dried ether extract is evaporated at low temperature under a weak vacuum. 41.5 g of α,α'-tetramethyl-(cyanomethoxy)-acetic acid are immediately obtained, which

corresponds to a yield of 81% of the theoretical. This crude product melts at 69-71°C and meets, in terms of purity, most requirements (acid number found: 327, acid number calculated: 328). During recrystallization, significant losses (up to 60%) occur through the formation of by-products. An acid with the following properties is obtained from gasoline:

Acid number found: 330, calculated: 328

N found: 8.25%, calculated: 8.18% Smp. 72.5°C for the colorless crystals.

By reacting the potassium salt of the above-mentioned (cyanomethoxy)-acetic acid with an excess of dimethyl sulfate in a benzene-water slurry at boiling temperature, α'-tetramethyl-(cyanomethoxy)-acetic acid methyl ester is obtained. This compound has the following properties: Saponification number found: 575 Saponification number calculated: 605 Refractive index at 20°C: 1.4262

Boiling point of the water-clear colorless liquid at 0.3-0.4 mm Hg: 38-40°C.

Example 2.

To prepare the starting material 4-isonitroso-2,2,5,5-tetramethyl-3-oxotetrahydrofuran (the α-oximation product of 2,2,5,5-tetramethyl-3-oxotetrahydrofuran), 0.2 mol of 2,2,5,5-tetramethyl-3<:>oxotetrahydrofuran with 0.22 mol of amyl nitrite at 40-50°C and in the presence of 7.5 ml of concentrated hydrochloric acid. Already during the stirring, more than 65% of the theoretical quantity of the α-oximation product is obtained. The product can be recrystallized from dimethyl ether (m.p.: 127°C, Found: 8.07% N, Calculated: 8.18% N).

When 1 mol of an aqueous 30% sodium hydroxide solution is added to the reaction mixture, ring cleavage occurs. The (cyanomethoxy)-acetic acid can be isolated as in example 1 in the form of its alkali salt. If this (cyanomethoxy)-acetic acid is not isolated, but remains in the reaction medium, a strong ammonia evolution occurs. With the help of water vapor and during heating, the released ammonia and the amyl alcohol originating from the oxidation are removed through a downward-sloping cooler. The reaction product is colored red-brown when alkali is added, and it becomes lighter during the reaction. The reaction is finished as soon as the distillate is free of ammonia. To transfer in free acid, adjust the pH value little by little with concentrated hydrochloric acid at approx. 90°C to approximately 2, or it is neutralized with a total of 1 mol of HC1. From the slightly yellow colored reaction solution, the 2,2'-tetramethyl-diglycolic acid quickly crystallizes as a colorless product in an amount of approx. 80% of the theoretical. It is sucked off at 60°C. The acid can be freed from trapped alkali-potassium chloride by recrystallization from water or benzene, or simply by washing with water. Its melting point is at 158°C (acid number calculated: 590, found: 580, C calculated: 50.5%, found 50.5%. H calculated: 7.4%, found 7.4%, N calculated: 0, 0%, found 0.3%).

If, instead of • caustic soda, a corresponding amount of caustic soda with a concentration of approx. 40% is used, the yield increases to approx. 90% of the theoretical amount.

In an analogous manner and with at least equal yields, the corresponding diglycolic acids are obtained by the use of higher substituted α-oximation products, e.g. from the α-oximation product of 2,5-dimethyl:2,5-diethyl-3-oxotetrahydrofurah the corresponding 2,5-dimethyl-2,5-diethyl-diglycolic acid is obtained. It melts at 151°C.

If the reaction with alkaline lye is carried out in an analogous manner with α-oximation products purified by recrystallization, the expected diglycolic acids are obtained after neutralization with hydrochloric acid with equally high yields.

Example 3.

By heating 0.0585 mol of a 98.8% a-oximation product of 2,2,-5,5-tetramethyl-3-oxotetrahydrofuran in 40 g of toluene as suspending agent, and 0.2 g of NaOH as catalyst, to boiling point, the reaction ends after 2 hours, which can be ascertained by the negative detection of carbonyl groups with 2,4-dinitrophenylhydrazine. 48% of the theoretical amount of 2,2,5,5-tetramethyl-diglycolimide immediately crystallizes from the vacuum evaporated residue. A further 37% is obtained by recrystallization of the residue from 1% hydrochloric acid, which gives a total yield of 85%. When the reaction is carried out analogously in the absence of NaOH, the reaction lasts 9 hours and the isolated yields are approximately 30% lower. If toluene is replaced by the lower boiling benzene, the reaction time increases in the presence of NaOH. not significantly, but in the absence of NaOH it smokes to approx. 12 hours. In higher-boiling xylene, the reaction is finished in the presence of NaOH after 1.5 hours, and in the presence of n-butyl titanate already after 45 minutes. At 150°C in boiling dimethylformamide, a complete reaction takes place in the absence of reaction-accelerating additives within 3.5 hours. When the temperature increases further, the reaction times can be shortened even more even in the absence of catalysts.

Example 4.

A mixture consisting of 0.2 mol of α-oximation product of 2,2,5,5-tetramethyl-3-oxotetrahydrofuran, 5% by weight calculated on this product of n-butyl ortho-titanate as esterification catalyst, and 0.22 mol of n-butanol , is slurried in excess benzene and heated to boiling under reflux on a 10 cm long packed column with a column head. The separated esterification water is removed as distillate. As an upper layer, approx. 1.5 ml of water (= 41.7% of the theoretical).

The solvent (benzene) and the n-butanol excess are removed by distillation. An oily residue mixed with crystals is formed. With petroleum ether, the crystalline portion is dissolved and crystallized again. After recrystallization from benzene, 7.8 g of 2,2,5,5-tetramethyl-diglycolimide are obtained, corresponding to a yield of 23% of the theoretical. The substance melts at 137°C, and it was found 7.95% and calculated 8.18%.

Distillation of the residue leads to iso-

the formation of 21.9 g of 2,2,5,5-tetramethyl-digly-chol-N-n-butyl substituted imide. /Kp at 0.3 mm Hg = 77°C, C calculated 63.4%, C found 63.3%, H calculated 9.3%, H found: 9.3%, Ncalculated: 6.17%, Nfound: 6.0%/. The yield of 21.9 g corresponds to 48% of the theoretical. Thus, the isolated total yield amounts to 23.0% + 48% = 71% of the theoretical. Infrared spectra-of the two. isolated substances correspond to the assumed formulas. Both agree. transfer with moderately concentrated hydrochloric acid (concentration 10-25%) in excess, to a-oxyisobutyric acid.

Using a larger excess of n-butanol increases, as expected, the yield of decarboxyl reimides.

Instead of n-butyl titanate, small amounts of NaOH can also be used as a catalyst. This increases the yield of unsubstituted diglycolimide at the expense of the substituted compound, and at the same time the reaction time is extended from 1 hour to 2 hours.

Example 5.

0.176 mol of the a-oximation product of 2,2,5,5-tetramethyl-3-oxotetrahydrofuran is dissolved in 120 g. et<y>lalcohol, 0.5 g NaOH is added and. it heats up during backflow. It is extracted from, and into samples, and', the course of the reaction is controlled using typical reagents on free keto groups (e.g. 2,4-dinitrophenylhydrazine). After approx. After 3 hours, the reaction is complete. Small <" side reactions (saponifications) appear during ammonia decomposition.

By working as indicated in example 2, isolate: approx. 60% of the theoretical of 2,2,5,5- tetramethyldiglycolimide («^'-secondary dicarboxylic acid amide diisopropyl ether).

about. 35% of the theoretical of 2,2;5,5-tetramethyl-diglycol-N-ethyl-imide ( a,- a - secondary dicarboxylic acid amide-N-ethyl diisopropyl ether).

in total approx. 95% overall yield.

The infrared spectra of the reaction products correspond to the theoretical ones.

The impact of a reaction accelerator can be ascertained by comparing the reaction times for parallel experiments. By omitting NaOH, the reaction is not yet finished after 8 hours, but if sodium ethylate is used instead of NaOH, the reaction is already finished after 30 minutes.

Example 6.

A solution of 0.2 mol (= 34.2 g)

of the a-oximation product of 2,2,5,5-tetramethyl-3-oxotetrahydrofuran in 100 g

pyridine is heated with stirring to 80°C,

and 0.22 mol of benzene sulphochloride is added dropwise. An exothermic reaction occurs. The reaction temperature is maintained

at 80°C using slight cooling. The cooling process is interrupted when the dropwise addition is finished. The reaction is allowed to complete. 26 g ( = 80.5% of it) are immediately obtained from the reaction solution

theoretical) of an N-substituted diglycolimide with formula (V) melting at 156°C

which can be purified by recrystallization from

acetone. (N found: 8.68%, N calculated: 8.63%).

Example 7.

In a bowl, intimately rub together 0.1 mol

(= 17.1 g) of a,a'-secondary dicarboxylic acid imide diisopropyl ether (as an agent

with ring cleavage ability) and 0.1 mol of the α-oximation product of 2,2,5,5-tetramethyl-3-oxotetrahydrofuran, and the mixture

is heated slowly in a stirrer underneath

backflow. At 80°C, mixing begins

to melt, and at 90°C an exothermic reaction begins, whereby the reaction mixture is heated by itself to

150°C. After a few minutes, the reaction is complete, and a very

viscous mass that crystallizes slowly. The turnover is complete, and they

common reactions to detect ketones

proceeds negatively. Upon recrystallization

from benzene, 25 g of 2,2,5,5<:>tetramethyl-diglycolimide with a m.p. at 135—

137°C.

Claims (1)

Process for the production of α-α'-tetraalkyl-substituted (cyanomethoxy)-acetic acids with the general formula: where R,, R2, R1( R4 means methyl or ethyl residues, and their derivatives, which by ether cleavage or hydrolysis can be cleaved into α-oxycarboxylic acids, characterized in that 4-oximino-2,2,5,5-tetraalkyl-substituted 3 -oxotetrahydrofurans with the general formula: treated at temperatures of 40-200°C with water, alcohol or an organic solvent inert to carboxyl and/or nitrile groups with a boiling point above 75°C during ring cleavage between C(S) and C(4), and the formed a,a '-tetrasubstituted (cyanomethoxy)-acetic acids are optionally transferred to the corresponding diglycolimides or diglycolic acids by further treatment with the aforementioned reaction medium, optionally in the presence of esterification or transesterification catalysts or in the presence of anhydride-forming compounds.