DD207916A1 - PROCESS FOR PREPARING BROMOUS POLYOLS - Google Patents

Abstract

THE INVENTION DESCRIBES A PROCESS FOR PREPARING BROMINATING POLYOLS RELATING TO POLYOL MIXTURES COMPRISING A HOMOEOPOLAR-BONDED BROMANE BETWEEN 3 AND 50 MASS PERCENT BASED ON 2,3-DIBROME BUT-2-EN-1,4-DIOL. COMPOUNDS OF THIS TYPE ARE SUITABLE FOR OBTAINING PERMANENTLY FLAME-RESISTANT POLYMER MATERIALS. ACCORDING TO THE OBJECTIVE OF THE INVENTION TO SUMMARY A TECHNICALLY EASILY SYNTHESIS METHOD FOR BROMINATING BIOTHERAPPY AND HIGHER FUNCTIONAL POLYETHERAL CARBOHINES, THE INVENTION WOULD APPLY TO FORMALDEHYDE 2 TO 6-FUNCTIONAL POLYETHEROL POLYOLS AND 2,3-DIBROM-BUT-2-EN-1,4-DIOL IN THE PRESENCE OF ACIDIC CATALYSTS UNDER WATER TREATMENT. D. OBTAINED CLEAR BROMBUTENDIOLACETALPOLYOLE, THE MAXIMUM PRO OH GROUP OF A polyether polyol DIBROMBUTENDIOLEINHEIT HAVING CAN ARE AT ROOM TEMPERATURE medium viscosity to pasty AND IN ANY RATIO WITH USUAL, FOR EXAMPLE IN POLYURETHANE CHEMICALS USED POLYOLS BASED alkoxylated ALCOHOLS miscible.

Description

• IN · .- V. W · ^; Hl · ^ - U »

Title of the invention

Process for the preparation of brominated polyols

Field of application of the invention,

The invention relates to a process for the preparation of bromine-containing polyols or polyol mixtures having a homopolar bonded Bromanteil 3-50% based on 2 _f 3-dibromo-but-2-en-l, 4-diol · Such compounds are for flameproofing equipment Plastics, u. A. suitable for the production of permanently flame-retardant polyurethanes.

Characteristic of the known technical solutions

The preparation of 2,3-dibromo-bui-2-en-1,4-diol, which is described as a flame-retardant monomer for polyurethanes, polyesters and epoxy resin systems (GA »F. Bulletin No. 9649-001, 1971), takes place However, the use of this component in the polyurethane system is problematic since the dibronibutendiol precipitates as a solid from the mixtures used with low-viscosity polyethers quickly and also a parallel running polyaddition of polyether polyol and dibromodediol with Isocyanates are highly unlikely. The viscosity increase occurring during the polyurethane formation process excludes dibromobutenediol from

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Because of diffusion inhibition, the bromine-containing diol increasingly separates from the R @ actiofisg @ ai8ch and ultimately as an additive

in polyurethane © rbl © ibt »·

To Ver''tduog'dieses unwanted effect different methods are proposed with the aim of improving the compatibility of dibromobutenediol for use in polyurethane synthesis. This is possible according to US Patent 3,933,690 by means of stable homogeneous mixtures of dibromobutenediol and, for example Polyoxypropylensorbitol, a OH number between 337 and 462 and an acid number of about 8 "In the treatment of the immiscible starting components under the indicated reaction conditions of acid catalysis at 70 C are likely to side by side chain cleavages and linkages involving the Dibrombutendiols uncontrolled instead, so that the result is a homogeneous, but generally strongly dark-colored mixture »

According to DE-PS 2,327,116, the incorporation into the chemical structure of the polyurethane by the formation of a common prepolymer of dibromobutenediol with other H-active compounds and organic polyisocyanate and its subsequent reaction with up to 7 % alkylene oxides succeed

Another method for obtaining dibromobutene derivatives is described in British Pat. No. 1,412,384. Thereafter, epichlorohydrin is first added to butene- or butyne-1,4-diol after cationic initiation and, in a second stage, to the double or triple bond bromine »Chloro and bromo-containing diols are formed which contain C ₄ H ₄ Br ₂ -, C ₄ HgBr ₂ - and CHBr ^ units in the molecular chain and which depend on the added amount of epichlorohydrin '- 3 to 16''B) Ol per mole of alkene or Alklndiol - relative molar masses between 520 and 1730 and OH numbers between

·. '7 O Q η _t > · ι. r

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63 and 208 have varying proportions between 9 and 30 mass%, the chlorine content is in the range of 20 and 30 Ms @ s © proz @ ni · 0er part of the process consists in the fact that in this way only Oiole are accessible and each Möiekßlkette only 1 molecule of the starting substance for the Epichlorhydrinaddition serving / unsaturated diol is contained »that in the second reaction step is partially or exhaustively brominated. In this way, the maximum achievable bromine content of the product is limited. It is 2, depending on the degree of bromination and the nature of the unsaturated diol, and a maximum of 4 gram bromine per gram molecule of the flameproofing agent "" when the butynediol is used. ·

A further possibility for the combination of polyols with 2,3-dibromo-but-2-en-1,4-diol is described in US Pat. No. 3,936,426. Thereafter, a so-called living polymer is produced from tetrahydrofuran under fluorosulphonic acid catalysis Use of dibromobutenediol performed. This gives rise to linear diols with OH numbers between 74 and 130 and relative molar masses of between 750 and 1700. A decisive disadvantage of the process is a maximum achievable chain termination turnover of only 27 to 38 % , based on dibromobutenediol to be coupled even according to this technical teaching only diols result ·

Object of the invention

It is the object of the invention to provide a technically easy to carry out synthesis method for obtaining reactive bi- and higher functional bromine-containing polyether alcohols with a variable within wide limits proportion of carbon which are well compatible with other conventional polyols used in polyurethane chemistry and obtained on this basis Give polymer materials a permanent flame retardant behavior.

the goal tsdlrä achieved by a process for the production

or polyol mixtures with Bromareteil between 3 and 50 of 2 ₉ 3-dibromo-but ~ 2 «« ~

2-6 »functional polyether polyols with formaldehyde and 2,3» dibromo »but-2-ene« »l, 4-diol in the aqueous medium, in the organic phase or in the absence of fluidization of the reacting material - will be implemented (ffiischea causing aids in the presence säurer catalysts at 40 to 90 ⁰ C, preferably between 50 and 70 ⁰ C until complete removal of water, "as 2- to 6 =" functionally © Pölyetherpolyole be erfi'ndungsgemäß preferred the Examples of these are ethoxylated or propoxylated ethylene glycol, diethylene glycol, propanetriol / trimethylolpropane, pentaerythritol, sorbitol, diethylenetriamine and the like. The reaction products obtained according to the invention are represented by the structural unit of the formula

Br Br »

- O - CH ₂ --O - CH ₂ - C »C - CH ₂ - OH

characterized in the polyol molecule _f wherein the maximum number of this structural unit in the polyol molecule corresponds to the number of active hydrogen atoms in the polyether polyol.

Occurs DI® carrying out the method according to the invention advantageously in a Rßhrgefäß · The mixture of polyether "polyol, dibromobutene, and is added either in aqueous solution or in solid form as paraformaldehyde, formaldehyde, and an acidic catalyst forms ^Toggle: fangs" a heterogeneous but stirrable mass, which is carefully warmed up. "The discharge of water from the reaction mixture

)> -f ¹

Mixture can be carried out both in a vacuum and also in azeotropic mixture with suitable entrainment agent. riger formaldehyde solution is first solvent water, then condensation water removed by applying a vacuum. On the other hand, operating in the presence of an organic solvent, is carried out dss discharging the water of reaction in the mixture on a water azeotrepen "The reaction is completed after the heating period, generally within 1 to 4 hours at 50 to 70 ⁰ C. After a further 30 keeps the reaction product Hinuten nor the completion of the removal of water at the reaction temperature, is removed by introducing an equivalent to the initially charged as a catalyst amount of acid alkali such as sodium or potassium hydroxide, sodium or potassium carbonate, neutralized, and the resulting water of neutralization in vacuo · Subsequently, the still warm reaction mixture for the separation of the salt load over a G 2 frit is added, and there remains a bromine-containing, at room temperature, medium to pasty transparent polyol, which is yellow to brown color · molecular weight and hydroxyl number of the products produced in this way As far as possible, the values which follow from the characteristics of the polyether polyol used, taking into account the reaction carried out. A molecular weight increase is to be determined by an order of magnitude corresponding to the reacted dibromobutenediol units.

Owing to the variation of the quantitative ratio of polyether polyol and dibromobutenediol which is possible within wide limits for the reaction according to the invention, it being possible to couple a dibromobutenediol unit on average per QH group in the polyether polyol via an acetal bridge, bromine-containing polyols or polyol mixtures with

η a Halogenafteii between 3 and 50 percent by mass produced »

In this case, the reaction proceeds equally successfully on primary and secondary OH groups of the polyether polyol. In the attachment of 1 mol of dibromobutenediol to 1 mol of a polyether polyol, the product contains 2 g of bromine, so that 'in the. Assumption of a mean relative molar mass of

«3. '

For example, if the OH groups of a sorbitol-based polyether polyol having an average molecular weight of 520 gmol are exhaustively linked to dibromobutenediol moieties, this product reaches the maximum value of about 50% by weight Bromine. In contrast, the proportion of the components to be linked by means of the formaldehyde via the OH groups can also be selected such that only one OH group of every second polyether polyol molecule couples a dibromobutenediol unit via an acetal group. In this case, polyol mixtures with bromine-containing components result and Bromine-free molecular fractions, which have a total of only a low halogen content. The bromine-containing polyols or polyol mixtures according to the invention are irrespective of the amount of homo-polar bonded halogen content both with that for the reaction zugru In general, mixed polyether polyols can also be mixed in any ratio with other polyolefin components which are customary in polyurethane chemistry and optionally carry other heteroatoms and present themselves as stable, homogeneous mixtures.

Suitable polyether polyols for the process according to the invention are, in particular, the known commercial polyurethane precursors, regardless of their degree of branching and relative molecular weight. Typical representatives of this group are polyethylene and polypropylene glycols and ethoxylation and / or propoxylation products based on propanetriol, trirethylethylolpropane, pentaerythritol,

Sugar derivatives. wi @ sorbitol or diethylenetriamine

Suitable catalysts for the formation of acetals between polyether polyol and 2,3-oibromobut-2-en-1,4-diol according to the invention are in principle all compounds which are advantageously used in acetalization. P-toluenesulforic acid, dilute sulfuric acid and oxalic acid have proven particularly suitable also ion exchange resins doped with SOgH groups »

Exemplary embodiments Example 1

In a 750 ml sulfonation flask, 150 g of a polyethylene glycol oil having the relative molecular weight of 580 gem, 51 g of paraformaldehyde and 369 g of 2,3-dibromo-but-2-en-l, 4-diol in the presence of 2.25 g of p-toluenesulfonic acid Gently heat under vacuum. The initially inhomogeneous mass is homogeneous with stirring at about 40 ⁰ C, and between 50 and 55 ⁰ C begins in a set to -30 ⁰ C template / separation of the expelled condensation water · The process is complete after 3 hours. The mixture is then neutralized with 6 ml of 2.5% KOH and again stirred for 45 minutes in vacuo. The transparent product filtered through a G 2 frit is light brown in color and has a viscosity of 80 Pa.s at 25 ° C. The vapor pressure osmometric Determination of the relative molar mass gives 630 gmol. The acid number is 0.53, the OH number is determined to be 177, the water content is 0.403 %, the bromine determination indicates 44.2 % , which corresponds quantitatively to the amount used Tests for free bromine and bromide are negative · The bromine-containing polyol, which is miscible in any ratio with rigid foam polyols customary in polyurethane synthesis, has two functional OH groups «

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Example 2 ''''; , V '. · '''· -

Analogously to Example 1, the magnification is increased to 10 times · The bromine-containing product has the following properties:

Color: light brown, transparent

Viscosity at 25 ⁰ C: 82 Pa »s

relative molar mass (vapor pressure osmometric): 650 g mol "*

OH number: 175 .32 % % Acid number: 0 : 0.33 43.4 % kg water content o .% bromine content: 12:15 free bromine: 4.89 Bromide: Yield:

85.6 % based on stoichiometric sales

Example 3

2350 g of an alkoxylated Prppantriols (80 mol% propylene oxide, 20 MoI ^ ethylene oxide) having the OH number 87.5 and a relative molecular weight of about 1900 g mol "are mixed with 210 g of formalin solution (32 to 35%) and 450 g , 3-dibromo-but-2-ene-1,4-diol in the presence of 9.4 g of p-toluenesulfonic acid at 60 ⁰ C in vacuo · From the immediately readily stirrable, aqueous mixture escapes first introduced with the formalin water The condensation water is then driven off in a slow reaction over a period of 6 hours. Thereafter, it is neutralized with 16.1 ml of 20% strength KOH and the water resulting from the neutralization reaction is removed within 60 minutes. After filtration through a glass filter slide This results in 2.74 kg of the bromine-containing polyol with the following characteristic values

Color: yellow, transparent

-Ι relative molecular weight (vapor pressure osmometry): 1950 g mol

Viscosity at 25 ⁰ C: 48 Pa «s

O ^ O>; /

OH Zahls 91 Acid number σ 0.24 Water content $ 0.41 Bromgehelt: 13.34 frei®8 Bro®: O % Bromide; 0 _s 2 Example 4

88 g of a propoxylated propane triol having the OH number and a relative molecular weight of about 440 g mol are mixed with 18 g of paraformaldehyde and 144 g of 2,3-dibromo-but-2-en-1,4-diol in the presence of 1 g of toluenesulfonic acid After 4 hours, neutralize with 3 ml of 10% KOH. The neutralized reaction mixture is filtered after expelling the neutralization water for 30 minutes; there remain 235 g bromine-containing polyol having the following properties;

Color yellow

Viscosity at 50 ^P C: 62 Pa «s

relative molar mass (vapor pressure osmometric): 730 g mol OH number: 230

Acid number: 0.14

Water content: 0.15 %

Bromine content: 41.6 %

free bromine: 0 %

Bromide: 0.05 % · '

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Example 5

100 g of sorbitol polyol having an average of 1.5 propylene oxide units per OH group and an OH number of 470 are suspended with 25 g of 2,3-dibromo-but-2-en-1,4-diol in 400 ml of toluene then 4.5 g of paraformaldehyde and 0.4 g of p-toluenesulfonic acid added. With stirring, the reaction mixture until the beginning of the separation of water at

Λ ' D

* «%? % # S "%% & V * ·

80 ⁰ C heated up Within 2 hours the Scbleppsiiitt ©! a total of 2.1 ml of water aisgetragen; In this liquid above the stoichiometric conversion amount residual wastewater of the starting substances is contained. Subsequently, ¹ is neutralized with 0.7 ml of 20 % pure KOH. Then, residual toluene is distilled off in vacuo and the product of the Surapf is filtered. Aisbeute 118 g # It follows from the stoichiometry of the approach that, on average, every 2 molecules of the sorbitol polyol is linked to a bromobutene diol molecule by acetal formation. The bromine-containing polyol has the following properties; Ί.

Color: dark brown

Viscosity at 50 ^° C .; 94 Pa »s

relative molar mass (steam pressure osmometry) 644 g raol "*

OH number: 510 Acid number; 0.47 Water content; 0.11 bromine content; 13.3 free bromine; 0 Bromide: 0.1

Claims (3)

ώ. - Claim for invention 1. A process for the preparation of bromine-containing polyols or polyol mixtures having a homopolar bonded Bromanteil between 3 and 50 percent by mass based on 2 _(J 3-dibromo-but-2-en-l, 4-diol, characterized in that 2-6 Functional polyether polyols with formaldehyde and 2,3-dibromo-but-2-en ~ l, 4-diol in an aqueous medium, in the organic phase or in the absence of fluidization of the reacting substance mixture causing aids in the presence of acidic catalysts at 40 to 90 ⁰ C, preferably between 50 and 70 ⁰ C, are reacted until complete separation of water · 2 * Process according to item 1, characterized in that the alkoxylation products of compounds carrying active hydrogen atoms are used as 2 to 6-functional polyether polyols · 3. The method according to item 1 and 2, characterized in that in the polyol molecule of the reaction products, the structural unit of the formula Br Br I!
- 0 - CH ₂ -, 0 - CH ₂ - C - C - CH ₂ - OH is contained and the maximum number of this structural unit in the polyol molecule is determined by the number of active hydrogen atoms of the polyether polyol.