Process for the production of biscyanoacrylates
AssigneeHenkel Kommanditgesellschaft auf Aktien
InventorsYuri Gololobov, Werner Gruber, Christian Nicolaisen
Life of this patent
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Abstract
Biscyanoacrylates in solution are prepared by reacting 2-cyanoacrylic acids or their alkyl esters with diols in the presence of sulfonic acids as catalysts. The reaction mixture is processed by substituting an aliphatic solvent for the aromatic solvent and is then subjected twice to fractional crystallization. The thus obtained biscyanoacrylates are very pure. They are therefore useful for producing storage stable cyanoacrylate adhesives. Their admixture increases the thermal resistance of the adhesives, which is particularly important in the case of electric and electronic components.
Claims19
A process for the production of a biscyanoacrylate corresponding to the following general formula:
- [H.sub.2 C.dbd.C(CN)--CO--O].sub.2 R.sup.1 (I)
- wherein R.sup.1 is the residue of a diol, which comprises the steps of:
- esterifying a 2-cyanoacrylic acid or transesterifying an alkyl ester thereof corresponding to the following general formula:
- H.sub.2 C.dbd.C(CN)--CO--O--R.sup.2 (II)
- in which R.sup.2 is selected from the group consisting of hydrogen and branched and unbranched alkyl groups containing 1 to 6 carbon atoms with a diol corresponding to the following general formula:
- [HO].sub.2 R.sup.1 (III)
- to obtain a reaction mixture;
- and
- fractionally crystallizing the reaction mixture to obtain the biscyanoacrylate.
A process for the production of
- a biscyanoacrylate corresponding to the following general formula:
- [H.sub.2 C.dbd.C(CN)--CO--O].sub.2 R.sup.1 (I)
- wherein R.sup.1 is the residue of a diol, which comprises the steps of:
- esterifying a 2-cyanoacrylic acid or transesterifying an alkyl ester thereof corresponding to the following general formula:
- H.sub.2 C.dbd.C(CN)--CO--O--R.sup.2 (II)
- in which R.sup.2 is selected from the group consisting of hydrogen and branched and unbranched alkyl groups containing 1 to 6 carbon atoms in the presence of a strong acid catalyst and in the presence of a solvent selected from the group consisting of aromatic hydrocarbons and halogenated hydrocarbons and mixtures thereof with a diol corresponding to the following general formula:
- [HO].sub.2 R.sup.1 (III)
- to obtain a reaction mixture;
- and
- fractionally crystallizing the reaction mixture in a solvent selected from the group consisting of hexane, heptane and decane and mixtures thereof biscyanoacrylate.
A process for the production of a biscyanoacrylate corresponding to the following general formula:
- [H.sub.2 C.dbd.C(CN)--CO--O].sub.2 R.sup.1 (I)
- wherein R.sup.1 is the residue of a dial selected from the group consisting of hexane-1,6-dial, octane-1,8-diol, decane-1,10-diol, dodecane-1,12-diol and mixtures thereof which comprises the steps of:
- transesterifying an alkylester of a 2-cyanoacrylic acid corresponding to the following general formula:
- H.sub.2 C.dbd.C(CN)--CO--O--R.sup.2 (II)
- in which R.sup.2 is selected from the group consisting of branched and unbranched alkyl groups containing 1 to 6 carbon atoms in the presence of about 1 to about 20 wt. % soluble sulfonic acid catalyst and in the presence of a solvent selected from the group consisting of toluene and xylene and mixtures thereof with a diol selected from the group consisting of hexane-1,6-diol, octane-1,8-diol, decane-1,10-diol, dodecane-1,12-diol and mixtures thereof to obtain a reaction mixture;
- and
- fractionally crystallizing the reaction mixture in a solvent selected from the group consisting of hexane, heptane and decane and mixtures thereof to obtain the biscyanoacrylate.
Dependencies are inferred from the claim text.