DE1248670B - - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

PATENT LETTERING

Int. CL:

Number:

File number:

Registration date:

C07d

German class: 12q-25

U 8904IV b / 12 q

April 30, 1962

August 31, 1967
March 14, 1968

Display day:

Issue date:

The patent specification corresponds to the patent specification

The production of glycol monoborate esters has hitherto been expensive, ineffective and time consuming. According to a known process, these compounds are prepared in a two-stage process, an o-boric acid ester being first prepared in a first stage from a boron compound and an alcohol, which is then transesterified in a second stage with a glycol in the presence of an azeotropic agent. This procedure takes about 8 to 24 hours; a large excess of alcohol is required, the yields, based on the substances used, being low.
• It has now been found that cyclic boric acid esters of the general formula

■ ■ '■ ': '' ■ ■

R ₁ OB

in which R represents a hydrocarbon radical containing 2 to 20 carbon atoms, with 2 to 4 carbon atoms being connected as an alkylene chain to the two oxygen atoms, and R ₁ an unsubstituted alkyl group with 3 to 20 carbon atoms, a cycloalkyl group or an arylalkyl group, the alkyl part of which contains at most 6 carbon atoms , means, obtained in a simple manner and with good yields by using a monohydric alcohol of the general formula R ₁ OH, a glycol of the general formula HO - R - OH, where R ₁ and R _{2 have} the meanings given above, and boric acid heated to boiling in equimolecular amounts in the presence of a hydrocarbon solvent and the water of reaction formed is distilled off azeotropically, or that the monovalent process for the preparation of cyclic
Boric acid esters

Patented for:

United States Borax and Chemical Corporation,

Los Angeles, Calif. (V. St. A.)

Representative:

Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse
and Dr. E. Frhr. v. Pechmann, patent attorneys,
Munich 9, Schweigerstr. 2

Named as inventor:

William George Woods, Anaheim, Calif .;

Irving Swem Bengelsdorf, "

Costa Mesa, Calif. (V, St. A.)

Claimed priority:

V. St. ν. America of May 1, 1961 (106 527) -

Alcohol, the glycol and the boric acid in equimolecular Amounts together until the boric acid is dissolved heated, the hot reaction mixture is mixed with a hydrocarbon as a solvent, the separated water of reaction is separated off and then the remainder by azeotropic distillation Water of reaction removed.

The course of the reaction of the process according to the invention is given by the following reaction equation illustrates:

R ₁ OH +

HO,

HO

R + H ₃ BO ₃ R ₁ O -

3H ₂ O

Compared to the known method, the method according to the invention has the essential advantage that it leads to the corresponding cyclic boric acid esters in one step and no longer reaction times required are.

Suitable monohydric alcohols are, for example Isopropyl alcohol, tertiary butyl alcohol, secondary amyl alcohol, n-octyl alcohol, n-dodecyl alcohol, Benzyl alcohol and / 3-phenethyl alcohol.

Examples of glycols are butane-1,2-diol, , Butane-l, 3-diol, propane-I, 2-diol, propane-l, 3-diol, ice-butane (2) diol (l, 4), Ethane-1,2-diol, 2-methylpentane-2,4-diol, butane-2,3-diol and cis-4,5-di (hydroxymethyl) cyclohexane suitable.

The reaction is carried out by heating a mixture of the reaction components to be used in the presence of a hydrocarbon solvent Boiling temperature carried out.

The process can also be carried out in such a way that a corresponding alcohol, the relevant Glycol and boric acid are first heated together until all of the boric acid is in

■. 809 516/368

Solution has gone, and then the hot reaction mixture uses a hydrocarbon as a solvent admitted. This makes it possible to keep half to about two thirds of the water of reaction on the bottom to separate the reaction vessel and this preferably by pouring off or decanting the upper Remove hydrocarbon layer. The hydrocarbon phase is then heated to the boil and the remaining water of reaction is removed by azeotropic distillation.

The separation of water is largely facilitated if there is an excess of the solvent in question is used. Preferably 1 to 4 volumes of hydrocarbon used as a solvent per volume of reactants. Suitable hydrocarbon solvents are for example benzene, xylene, n-heptane and toluene.

The process products are used as epoxy resin hardeners and for the manufacture of other plastics Adhesives and coating materials used. They are also used as electrolytes in capacitors, as Anti-resin agent in lubricating oils and can be used as fuel additives. They are also available as Herbicides and pesticides as well as bacterial growth inhibitors are suitable and represent important intermediate products for the production of other organoboron compounds.

The following examples explain the process according to the invention.

B e i s ρ i e 1 1 B e i s ρ i e 1 3

A mixture of 216 g (2 mol) of benzyl alcohol, g (2MoI) butane-1,3-diol and 123.8 g (2MoI) boric acid was placed in a 2-1 round bottom flask fitted with a Dean-Stark receiver and a Magnetic stirrer was equipped and contained 900 ecm of toluene, single. The mixture was ^{heated to boiling for 2 1} ^ hours, the theoretical amount of water

ao distilled off from 108 ecm. For this purpose, the remaining toluene was distilled off from the reaction mixture and 346.6 g, ie 84.2% yield, 2-benzyloxy-4-methyl-l, 3,2-dioxaborinane from Kp. O, 3Wso, 4124-125 ⁰ C obtained from the residue.

Analysis in percent by weight for C _n H ₁₆ O ₃ B: Calculated: B 5.27; found: B 5.31.

Example4

A mixture of 250 g (2.5 mol) of cyclohexanol, ao 225 g (2.5 mol) of butane-2,3-diol and 154.5 g (2.5 mol) of boric acid was dissolved in a 5- 1 round flask, which was equipped with a Dean-Stark template and a magnetic stirrer, introduced. The mixture was heated to boiling for 2 hours, the theoretical amount of water of 135 ecm distilling off. Then, the remaining toluene from the residue 404.1 was g, ie 81.7% yield, 2-cyclohexyloxy-4,5-dimethyl-l, 3,2-dioxaborolan from Kp. ₀ received ₅ 71 to 74 ° C .

Analysis in percent by weight for C ₁₀ H ₁₉ O ₃ B: Calculated: B 5.47; found: B 5.49.

A mixture of 370.6 g (5 moles) of n-butyl alcohol, 590.9 g (5 moles) of 2-methylpentane-2,4-diol and 309.2 g (5 moles) of boric acid was placed in a 5-1 round bottom flask , which was equipped with a Dean-Stark template and a magnetic stirrer and which contained 1750 ecm of benzene, introduced. The mixture was heated to boiling for 3 hours, the theoretical amount of water of 270 ecm distilling off. The benzene was then removed from the reaction mass by distillation over a 60 cm Vigreux column. There are 805.3 g (80.5% of theory) of 2-n-butoxy-4,4,6-trimethyl-l, 3,2-dioxaborinane from Kp. _Ois earn 43 up to 57 ° C.

Analysis in percent by weight for C ₁₀ H ₂₁ O ₃ B: Calculated: B 5.41; found: B 5.42.

Example 2

A mixture of 37.1 g (0.5 mol) of n-butyl alcohol, 59.1 g (0.5 mol) of 2-methylpentane-2,4-diol and 30.9 g of boric acid was placed in a flask and so long heated until all the boric acid was dissolved. 200 ecm of benzene were then added to the hot reaction mass, 16 ecm (59.3%) of water being separated from the mixture as the lower layer in the flask. The water was drawn off, the residue was transferred to a 500 cc round bottom flask with a receiver and heated to the boil for 2 ¹ I _{2 hours.} The remaining water (110 ecm) distilled off azeotropically. The benzene was then driven off from the reaction mixture and 77.9 g (78% of theory) of 2-n-butoxy-4,4,6-trimethyl-1,3,2-dioxaborinane from JKp. ^ J 8O ⁰ C from the residue receive.

Analysis in percent by weight for C ₁₀ H ₂₁ O ₃ B: Calculated: B 5.41; found: B 5.45.

Claims (2)

Patent claims: 1. Process for the preparation of cyclic boric acid esters of the general formula R ₁ O-B ,O, in which R represents a hydrocarbon radical containing 2 to 20 carbon atoms, with 2 to 4 carbon atoms being connected as an alkylene chain to the two oxygen atoms, and R ₁ an unsubstituted alkyl group with 3 to 20 carbon atoms, a cycloalkyl group or an arylalkyl group, the alkyl part of which contains at most 6 carbon atoms , means, characterized in that one. a monohydric alcohol of the general formula R ₁ OH, a glycol of the general formula HO - R - OH, where R ₁ and R _{2 have} the meanings given above, and boric acid is heated to boiling in equimolecular amounts in the presence of a hydrocarbon as a solvent, and that here resulting water of reaction is distilled off azeotropically or that the monohydric alcohol, the glycol and the boric acid are heated together in equimolecular amounts until the boric acid is dissolved. A hydrocarbon solvent is added to the hot reaction mixture, the water of reaction which has separated out is separated off and the remaining water of reaction is then removed by azeotropic distillation. 2. The method according to claim 1, characterized in that 1 to 4 volumes of the hydrocarbon used as solvent per volume of reactants. , 709 639/533 8.67 © Bundesdruckerei Berlin