DE102004047894B3 - New polymeric mercapto-terminated polysulfides with ester groups and intermediates for their preparation - Google Patents

Abstract

Polymeric polysulfides containing mercapto groups and processes for their preparation which have been prepared by reacting formaldehyde with monomeric dihydroxyalkyl-terminated disulphides and esterifications of the resulting hydroxyalkyl-terminated polymeric polysulfide with a carboxylic acid or carboxylic acid derivatives such as carboxylic acid esters bearing a mercapto group or by esterification are described corresponding carboxylic acids, carboxylic acid esters or carboxylic acid halides which have an unsaturated olefinic double bond, and reaction of the product having olefinic double bond having hydrogen sulfide or bismercaptans.

Description

The The invention relates to novel mercapto group-containing polymeric polysulfides and a process for their preparation and intermediates, the polysulfides containing the polymeric mercapto groups can serve.

Mercapto-containing polymers have been known for a long time. So be in the EP 0 171 198 B1 such polymers described. To prepare these substances, a process is used in which an epoxy resin having an epoxy group content of 2 to 6 mol / kg is reacted with a mercapto-terminated polymer having at least two mercaptan groups per molecule and a molecular weight not exceeding 2,000; while a curable liquid block copolymer is obtained.

The there described substances called prepolymers, are stable to viscosity only after a few weeks. Also, the implementation takes relatively long. Furthermore, as far as their uniformity is concerned, these products to be desired.

Also in the US 2,731,437 Mercapto-containing polysulfides are mentioned.

The hitherto known methods have u. a. the disadvantage that they are heavy are controllable, d. H. that it is extremely difficult is to obtain products that are both in their chemical structure as well as their molecular weight are uniform. That's how you often get at different approaches under identical reaction conditions corresponding polymers with different molecular weight distribution.

Also is the inconsistency, or polydispersity, within the individual approaches quite high. Also let the speeds with which the individual implementations are lost, to be desired. The corresponding processes are common highly corrosive and contaminated with high salt load.

It there is still a need for improved polymeric mercapto-containing polysulfides as well as improved manufacturing processes.

task The invention therefore has polymeric mercapto end groups Polysulfides available to ask, which is a cheaper Have molecular weight distribution (i.e. narrow distribution) targeted with a specific molecular weight can be produced and which are useful as valuable end or intermediate products.

task The invention is also a corresponding manufacturing method to disposal to make that easy and economical as well as possible Low-salt and low-corrosion, working through a high speed of the individual reaction steps and that leads to largely uniform products and that reproducible is working.

task It is further the object of the invention to provide intermediates from which in a simple manner the polymeric mercapto groups containing polysulfides can be obtained.

These Task is solved by a process for the preparation of polymeric mercapto end groups ester group-containing polysulfides, characterized in that Formaldehyde with a monomeric dihydroxyalkyl-terminated disulfide converts to a polymeric hydroxyalkyl-terminated polysulfide, this reaction product with a carboxylic acid or its esters, which carry a mercapto group, or by reacting with an unsaturated Carboxylic acid, their acid halide or which converts esters and the double bonds of the formed Esterification product with hydrogen sulfide or a bismercaptan reacted to the mercapto-terminated product.

When Formaldehyde is preferably used paraformaldehyde.

monomers Dihydroxyalkyl disulfides, in particular the so-called dithiodiglycol are known compounds.

In the context of the invention, however, a dithiodiglycol (also called bishydroxyethyl disulfide) which is prepared by a process according to German Pat DE 103 238 39 is obtained. According to the teaching of this patent, which is particularly incorporated herein by reference and incorporated herein by reference, mercaptoethanol is reacted with oxygen or an oxygen-containing gas in the presence of ammonia and / or amines using copper or manganese salts reacted to dithiodiglycol. A corresponding synthesis is described for example in Example 1 of the DE 103 238 39 described.

The Reaction of formaldehyde and bishydroxyethyl disulfide is per se also already known and is described for example in US PS 4,124,645 mentioned.

in the However, the preparation of the present invention is preferred of the hydroxyalkyl-terminated polymer polysulfide by a process carried out, that in the filed in the same priority German patent application (internal reference T 634) is described. According to this Process is formaldehyde in particular paraformaldehyde and bishydroxyethyl disulfide reacted in the presence of solid acidic catalysts.

Corresponding the teaching of this patent application, to which particular reference is made here and whose disclosure is included here, is this is a process for the preparation of polymeric hydroxyalkyl terminated Polysulfides by reacting bishydroxyalkyl monomeric polysulfides with Formaldehyde in the presence of acidic catalysts, thereby characterized in that the acidic catalyst in the form of a solid Acid, the water and optionally used solvent and the catalyst separates.

wobei R' ein aliphatischer Kohlenwasserstoffrest mit der Formel (-CH₂-)_x ist, x = 2 bis 4, und n = 4 bis 50 ist.The reaction according to reaction equation I reproduces the reaction of formaldehyde with dihydroxyalkyl disulfide to give the corresponding hydroxyalkyl-terminated polysulfide. Reaction equation I

wherein R 'is an aliphatic hydrocarbon radical of the formula (-CH ₂ -) _x , x = 2 to 4, and n = 4 to 50.

Preferably, R '= -CH ₂ -CH ₂ -

In In a second process step, the polymer is hydroxyalkyl terminated Polysulfide esterified either with a carboxylic acid or their esters, which carry a mercapto group or it is esterified with an unsaturated one Carboxylic acid, their acid halide or their esters, wherein a double bond esterification product which then forms with hydrogen sulfide or a bismercaptan reacted to the mercapto-terminated product.

wobei R'' ein aliphatischer Rest der Formel -(CH₂)_x- mit x = 1–4 ist.These steps are carried out according to reaction equations IIa or IIb. Reaction equation IIa Reaction with a mercapto acid or its derivative

wherein R "is an aliphatic radical of the formula - (CH ₂ ) _x - with x = 1-4.

Instead of the mercaptocarboxylic acid, the esters HS-R''COOR with R = -CH ₃ (methyl), -C ₂ H ₅ (ethyl), -C ₃ H ₇ (n- and iso-propyl) and -C ₄ H ₉ (n- and iso-butyl) are used. When using esters, the corresponding alcohol is liberated instead of water during the reaction.

The according to this Reaction equation having resulting mercapto end groups Polysulfides with ester functions are another subject of the Invention.

mit y = 0 bis 3 und R''' = H oder CH₃.In a further embodiment of the process according to the invention, the polymeric hydroxyalkyl-terminated polysulfide is reacted with an unsaturated carboxylic acid, its acid halide or its esters which have double bonds, then the esterification product having the double bonds is reacted with hydrogen sulfide or bismercaptan to give a product having mercapto end groups. This reaction follows the reaction equation IIb with subsequent reaction to IIc or IId. Reaction equation IIb Reaction with an unsaturated carboxylic acid or its derivatives

with y = 0 to 3 and R '''= H or CH ₃ .

at Use of the acid halide is expediently the liberated hydrogen halide with a base such as sodium hydroxide solution or triethylamine as a salt. In the case of the ester this applies carried out in reaction equation IIa. The according to this Reaction equation resulting polymer polysulfides with ester groups and double bonds (formula C) are another subject of the Invention.

she serve as intermediates for the preparation of the polymeric Mercpatoendgruppen having polysulfides according to the invention, can but e.g. also by radical polymerization to interesting new Lead polymers.

The Reaction to polymeric mercapto-terminated polysulfide from the unsaturated intermediates happens according to the following equation:

Reaction equation IIc

Reaction with hydrogen sulfide

The mercapto group can also be present as a secondary group: HS- (H ₃ C) CR '''- (CH ₂ ) _y -COO-R'SSR' - (OCH ₂ O-R'-SS-R '-) _n OCO- (CH ₂ ) _y -CR''' (CH ₃ ) -SH (Formula E)

Also can the two mercapto groups are asymmetric, d. H. one primary, the other secondary be arranged.

wobei R'''' -(CH₂)_z- ist mit z = 2–4
oder HS-R''''-SC(CH₃)R'''-(CH₂)_y-COOR'SSR'(-OCH₂OSSR')_n-OCO-(CH₂)_y-C(CH₃)R'''-SR''''-SH (Formel G) The polysulfides having mercapto groups described in the above formula scheme (formula D and E) are a further subject of the invention. Reaction equation IId reaction with a bismercaptan

where R "'is - (CH ₂ ) _z - with z = 2-4
or HS-R '''' - SC (CH ₃ ) R '''- (CH ₂ ) _y -COOR'SSR' (- OCH ₂ OSSR ') _n -OCO- (CH ₂ ) _y -C (CH ₃ ) R '''-SR''''- SH (formula G)

The according to the two Reaction equations (IId) resulting polymeric sulfides with ester groups (Formula F and G) are a further object of the invention.

at the reaction according to the formula scheme IId can also mercapto-containing polysulfides by the addition of bismercaptans, which is an asymmetric addition of the bismercaptan.

The Reaction of the hydroxy-terminated polysulfide with mercapto groups having acids or acid derivatives is preferably done in solution, where organic solvents such as toluene, benzene and the like are particularly suitable. Prefers becomes an acidic ion exchanger for the esterification and in the case the reaction with acid chlorides bases are used.

The reaction of the unsaturated polysulfides with hydrogen sulfide or alkandimercaptans is preferably carried out in a solvent such as toluene or benzene. The addition can be preferred by basic catalysts such as tertiary amines, in the case of dimercaptans accelerate preferably by radical initiators.

The The invention is further illustrated by the following examples:

example 1

Reaction of a hydroxy-terminated Polysulfides with thioglycolic acid

(according to reaction equation IIa)

150 g of a hydroxy-terminated polysulfide (M _n = 2200 g / mol) are dissolved in 200 ml of toluene and treated with an acidic catalyst (for example 2.5 g of Amberlyst 15), and then the reaction mixture is heated to max. Heated to 120 ° C. Subsequently, 26 g of thioglycolic acid are added carefully within 2 h. The reaction mixture is stirred for a further 6 h at this temperature. It is then filtered and the solvent removed in vacuo. There are 163 g of a low-viscosity slightly yellowish polymer (18 Pa · s) having a number average molecular weight of 2350 g / mol and a thiol content of 2.80%. (Formula B with R '' = -CH ₂ -)

Example 2

Reaction of a hydroxy-terminated Polysulfides with mercaptopropionic acid

(according to reaction equation IIa)

27 g of a hydroxy-terminated polysulfide (M _n = 2200 g / mol) are dissolved in 100 ml of toluene and admixed with an acid catalyst (for example 0.2 g of p-toluenesulfonic acid). Subsequently, the reaction mixture is heated to max. Heated to 100 ° C. Finally, 5.1 g of mercaptopropionic acid are added carefully over 2 hours. The reaction mixture is stirred for a further 6 h at this temperature. It is then filtered and the solvent removed in vacuo. 30 g of a low-viscosity slightly yellowish polymer (24 Pa.s) having a number-average molecular weight of 2300 g / mol and a thiol content of 2.85% are obtained. (Formula B with R "= -CH ₂ CH ₂ -)

Example 3

Acrylic termination with Acrylic acid chloride

(according to reaction equation IIb)

1400 g of a hydroxy-terminated polysulfide (M _n = 2300 g / mol) are dissolved in 1200 ml of toluene. At room temperature, 162 g of N-ethyl-N, N-diisopropylamine are slowly added dropwise. Subsequently, the reaction mixture is cooled to 10 ° C. 113 g of acrylic acid chloride are slowly added dropwise. The reaction mixture is heated to 50 ° C for 3 h. To complete the conversion is heated to 90 ° C for a further 3 h and then stirred at 60 ° C for 6 h. After the mixture has cooled to room temperature, it is filtered and the filtrate is concentrated. There are 1530 g of a low-viscosity slightly yellowish polymer (18 Pa · s) having a number average molecular weight of 2400 g / mol (Formula C wherein R '''= H and y = 0). NMR and IR spectra demonstrate the absence of hydroxyl end groups and the presence of terminal double bonds.

Example 4

Esterification with acrylic acid and completion the implementation by

Use of acrylic acid chloride

(according to reaction equation IIb)

300 g of a hydroxy-terminated polysulfide (M _n = 2200 g / mol) are dissolved in 400 ml of toluene and mixed with 60 g of acrylic acid. After addition of the acidic catalyst (5 g Amberlyst 15), the mixture is heated for 5 h at Wasserabscheider. After cooling the reaction mixture, the batch is neutralized and filtered. The filtrate is treated at room temperature with 5 g of ethyldiisopropylamine. Subsequently, the reaction mixture cooled to 10 ° C. 11 g of acrylic acid chloride are slowly added dropwise. The reaction mixture is heated to 50 ° C for 3 h. To complete the conversion is heated to 90 ° C for a further 3 h and then stirred at 60 ° C for 6 h. After the mixture has cooled to room temperature, it is filtered and the filtrate is concentrated. Solvent residues are removed in an oil pump vacuum. There are obtained 340 g of a low-viscosity, slightly yellowish polymer (25 Pa.s) of number average molecular weight of 2300 g / mol. (Formula C with R '' = H, y = 0).

Example 5

Implementation of an acryl-terminated Polysulfides with hydrogen sulfide

(according to reaction equation IIc)

2500 g of an acryl-terminated polysulfide prepared according to Example 3 or 4 (M _n = 2500 g / mol) are dissolved in 2000 ml of toluene and treated with a basic catalyst (10 g of triethylamine). Subsequently, hydrogen sulfide is introduced into the solution at room temperature. The temperature of the solution rises to about 30 ° C. The reaction is completed when a gas breakthrough in the downstream wash bottle is observed. In vacuo, the dissolved in the reaction mixture hydrogen sulfide is removed. Subsequently, the batch is filtered and the solvent distilled off.

It be 2550 g of a low-viscosity slightly yellowish polymer a number average molecular weight of 2600 g / mol and a Thiol content of 2.53%. (Formula D and E with R '' '= H, y = 0)

Example 6

Implementation of an acryl-terminated Polysulfides with ethanedithiol

(according to reaction equation IId)

500 g of an acryl-terminated polysulfide prepared according to Example 3 or 4 (M _n = 2500 g / mol) are dissolved in 300 ml of toluene and mixed with 60 g of ethanedithiol and homogenized. Subsequently, the catalyst system (peroxide / base, eg 5.6 g of t-butyl perbenzoate / 0.28 g of 1,1,3,3-tetramethylguanidine) is added carefully with cooling. After completion of the addition, stirring is continued for 15 minutes and then the reaction mixture is heated to 60.degree. After 12 hours, the excess ethanedithiol and the solvent are distilled off.

Solvent residues are removed in an oil pump vacuum. There are obtained 535 g of a yellow low-viscosity polymer having a number average molecular weight of 2700 g / mol and a thiol content of 2.44%. (Formula F or G with R '''= H, R''''= -CH ₂ -CH ₂ -, y = 0).

Claims (10)

Process for the preparation of polymeric mercapto-end groups containing polysulfides containing ester groups, characterized in that reacting formaldehyde with a monomeric dihydroxyalkyl-terminated disulfide to a polymeric hydroxyalkyl-terminated polysulfide, this reaction product with a carboxylic acid or its esters which carry a mercapto group, or by reacting with an unsaturated Carboxylic acid whose acid halide or ester reacts and converts the double bonds of the esterification product formed with hydrogen sulfide or a bismercaptan to Mercaptoendgruppen having product. Method according to claim 1, characterized in that that is used as formaldehyde paraformaldehyde. A process as claimed in claim 1 or 2, wherein the monomeric dihydroxyalkyl-terminated disulfide used is a bishydroxyethyl disulfide which, according to the teaching of the German Patent DE 103 238 39 has been prepared by reacting mercaptoethanol with oxygen or an oxygen-containing gas in the presence of ammonia and / or amines using copper or manganese salts to Bishydroxyethyldisulfid. Method according to one of claims 1 to 3, characterized in that one carries out the reaction to the polymeric hydroxyalkyl-terminated polysulfide by a method according to the same prio German patent application (internal file reference: T 634) deposited by reacting formaldehyde, in particular paraformaldehyde and bishydroxyethyl disulfide in the presence of solid acidic catalysts. Mercapto-terminated polysulfides having ester functions characterized by the formula: HS-R "- CO-O-R'-SS-R '(- OCH ₂ O-R'-SS-R') _n -O-CO-R" - SH where R 'is an aliphatic hydrocarbon radical of the formula (-CH ₂ -) _x , x = 2 to 4 and n = 4 to 50, R''is an aliphatic radical of the formula - (CH ₂ ) _x where x = 1 to 4 is. Polymer polysulfides with ester groups and double bond functions according to the formula CH ₂ = CR '''- (CH _{2) y} -COO-R'SSR' - (OCH ₂ O-R'SSR'-) _n OCO (CH _{2) y} -CR '''= CH ₂ where y = 0 to 3, wherein R ', and n have the meaning given above and R''' H or CH ₃ . Polymeric mercapto-terminated polysulfides of the chemical formula HS-CH ₂ CHR '''(CH ₂ ) _y COO-R'SSR' - (OCH ₂ OR'-SS-R'-) _n OCO- (CH ₂ ) _y -CHR ''' CH ₂ SH, where R 'R''', n and y have the meanings given above. Mercapto-terminated polymeric polysulfides of the formula: HS- (H ₃ C) CR '''- (CH ₂ ) _y -COO-R'SSR' - (OCH ₂ O-R'-SS-R '-) _n OCO- ( CH ₂ ) _y CR '''(CH ₃ ) -SH, where R' R ''', n and y have the meanings given above. Polymeric mercapto-terminated polysulfides of the formula: HS-R '''' SCH ₂ CHR '''- (CH ₂ ) _y COOR'SSR' - (OCH ₂ OR'SSR ') _n -OCO (CH ₂ ) _y CHR'''CH ₂ SR''''- SH, where R', R ''', n and y have the abovementioned meaning and R''''- (CH ₂ ) _z is z = 2 to 4. Polymeric mercapto-terminated polysulfides of the formula: HSR '''' SC (CH ₃ ) R '''- (CH ₂ ) _y COOR'SSR' (- OCH ₂ OSSR ') _n -OCO (CH ₂ ) _y -C (CH ₃ ) R''' SR '''' SH where R ', R''', R '''' and n and y have the meaning given above.