CS223304B1 - Method of preparation of the 1,4-dilithobutane by reaction of the 1,4-dichlobutane dilithiobutane by reaction of 1,4-dichlorbutane with lithium - Google Patents

Description

Process for preparing 1,4-dilithiobutane by reaction

1,4-dichlorobutane with lithium, characterized in that 1,4-dichlorobutane is reacted with lithium dispersed in an aromatic or saturated aliphatic hydrocarbon C6 or C7, preferably benzene, the particle size of the lithium being in the range of 40 to 100%. with stirring at a reaction temperature ranging from the boiling point of the hydrocarbon used to a temperature of up to 20 ° C lower, preferably at a temperature of 75 to 85 ° C.

The invention relates to a process for the preparation of ^: 1,4-Dithithiobutane by reacting 1,4-dichlorobutane with lithium.

1,4-Dithithiobutane is an important catalyst, particularly suitable for the polymerization of dienes to end-functional polymers: It is prepared by the reaction of 1,4-dichlorobutane with lithium according to the equation

Cl (CH 2) 4 Cl + 4 Li -? - Li (CH 2 -4 Li + Li Cl

The reaction is generally carried out in the presence of solvents, in particular ethers. Since the presence of ether causes the resulting 1,4-dicWorbutan has a limited shelf life In ^effect the reaction with ether and because also in the polymerization of 1,3-dienes: the preparation and blokovýc ^hk o ^p ol ^y mer ^ Э-сИтй styrene is The presence of undesirable ethers has been sought by methods for the preparation of 1,4-diithiobuane without their use. '...... ..... .......

It is known to make dilithioalkanů consist in the fact that in ^the hunt m ^é mill grinds a mixture ^of lithium metal with a dihaloalkane in the presence of a hydrocarbon solvent (US 2,947,793). The disadvantage of this method is the long reaction time, calculated to tens of hours.

Another method is also known in which a mixture of dihaloalkane with monohaloalkane in a molar ratio of 3: 1 to 1: 4 (US 3,886 C89) is added to the lithium-hydrocarbon dispersion at reflux. The disadvantage of this method is vznto vedtejmto ^to the genus ^{p i. The} organic solution at monolithioalkanu which must be from insoluble mixtures dilithioalkanu lithium chloride separated.

It is therefore an object of the present invention to provide a process for the preparation of 1,4-dilithiobutane which eliminates or substantially reduces the disadvantages of the known processes for its preparation in the absence of ethers, i.e. primarily to reduce reaction time while avoiding ball milling or adding .

This ^h o ^d axis ^{h of} U is caused to ^b em ^dL after EV ^{Y is N,} climb, consisting in the fact that the 1,4-ciiiithiobutan prepared by reaction of 1,4-dichlorobutane with lithium such that the 1,4-dichlorobutane is reacted with lithium dispersed in an aromatic or saturated aliphatic hydrocarbon, C6 or 07, preferably in benzene, wherein the particle size of lithium is in the range C to 1C0 microns, with stirring and at a reaction temperature in the range of about ^{d db} at reflux ^{fo p} ou t ^eh of uMovod ^ ^d at temperatures of up to 20: ° C lower, preferably at ⁷⁵ and ⁸⁵ ° C. Morn ^{t gives} an age of 1,4-dichlorobutane preferably progressively until reaching the stoichiometric ratio to lithium.

The hydrocarbons may be used benzene, toluene or heptane and the like. High howl ^{ease of product} with ^d axis U is ^{H é} especially when on. ^U sing benzene. It is in principle possible to use any uNovotfku, neolosahujmtoo oletímcké ^d War bond and having a boiling point in the range from 60 to 150 ° C.

Metallic Kthium is dispersed in the size ^{of the} puppy as a dispersion of size:. of particles. below 100 (microns. Conveniently an easily: available ^of a dispersion ^of a ^size: particle 4 ⁰ to -1 ° ^{0 _ /} tm, but: the nature of the reaction it is apparent that the corresponding: effect is also achieved when using the dispersion: of smaller particles.

Zn ^{and Mo,} the PMS ^0, 5-2, ⁰ ° / o ^h mot another alkali metal such as' sodium, has a beneficial effect on the _ accelerating the reaction of lithium with the organic halogen derivatives.

The vigorous stirring of the reaction mixture is an important component of a successful reaction. For instance, a cutter mixer at ³⁰⁰⁰ VHE not ^of rotation ^RC AC ^{h /} mm. ^{TI m: d} axis ^Ah _ not create adequate shear stress in the reaction mixture. , =

Since the reaction between 1,4-dichlorobutane ... and hthiem exotherm ^ ^d of the ^ADI realkčnr pulse ondenzac ^L O ^p ou ^s maiden ^{te dl} and reverse 'cMadiči or cooling the reaction vessel. The dependence of the reaction rate on temperature is considerable; it can be said that below a certain temperature, which is in the range of 20 to 30 ° C below the boiling point of the reaction mixture, the reaction does not proceed at a practically useful rate. When using benzene as the solvent, this critical temperature is about 70 ° C.

The process for the ^{preparation of} 1-dilithiobutane. .. after ^d le the invention is illustrated by the following Ex ^dy:

Example 1

Into a 1 liter flask equipped with a knife MIC ^H and ^{D rim can be} in ^the ovarnm ^{No. ER?} And ^{d flanging, p} Etna condenser and a thermometer under a protective argon atmosphere instilled -8 g of lithium dispersion in benzene. Lithium according to. 'Ana ^l yz ^y ^ fluff contained ^0, 8% ^h mot shorts. ^: The total amount of lithium in the feed rate according to the analysis, 2,088 mmol, dispersion had a particle size -0 to 100 microns. The reaction mixture was first heated to 75 ° C in an oil bath, then the bath was removed and, with vigorous stirring, 66.2 g (522 mmol) of 1,4-dichlorobutane was metered into the reaction mixture over a period of 50 min. Runs ^h em ^adjectives and ^the ub ^yl and te ^pl ota reality. The mixture was maintained at 75 ° C by cooling. After completion of ^{the bow} and ^{UB yl} and Ream mfcMna mixture for ¹⁰ mm ^ current ^ zahnv to ⁷⁵ ° C. The total reaction time was 1 h.

The reaction product was a suspension of 1,4-ёШthiobutanu and lithium chloride in benzene, which weighed 506 g by titration standardrnm mites ^to em ^HC1 obsaliovata ¹⁰³² mmo ^l alkalinity, indicating that the conversion of 1,4-dic ^hl orbutanu ^{was UPL} and n ^a. After ^{the addition} and ^the in ^di et ^hy l · ether and allyl bromide to aliquot sample before titration with a standard solution of HC1 vymteeto ^80% of the N ABT-CO ^from a ^DP OV ^{IDA 80%} above ^heavy at aktwnfto ^{ORG yes} ovu - l 4 - dilithiobutane.

Example 2

To 515 g of a dispersion of lithium in benzene, which ob

contained 224 mmol of lithium, at 75.5 ° C, 7.1 g (54 mmol) of 1,4-dichlorobutane was added over 12 minutes, the other conditions being identical to those of Example 1. The total reaction time was 22 min. 514 g of a suspension which contained 114 mmol of alkalinity was obtained, indicating a conversion of 100% The example shows that the reaction can be carried out at greater dilution with solvent.

Example 3

392 g of a lithium-toluene dispersion containing 1880 mmol of lithium and 59.7 g of 1,4-dichlorobutane were treated as in Example 1 except that the reaction temperature was 90 ° C and the feed time of 1,4-dichlorobutane was 90 min . The total reaction time was 100 min. 446 g of a slurry was obtained which contained 1066 mmol of alkalinity according to analysis, which corresponds to the conversion of cast iron in the reaction from

%. 21.6% of this alkalinity was active organometallic.

Example 4

290 g of a lithium-heptane dispersion containing 900 mmol of lithium and 28.6 g (225 mmol)

The 1,4-dichlorobutane was treated as described in Example 1 except that the feed time was 15 min and the reaction temperature was 98 ° C (reflux). The total reaction time was 25 min. 335 g of a suspension was obtained which, according to analysis, contained 436 mmol of alkalinity corresponding to 100% conversion of lithium in the reaction. Of this, 23% was active 1,4-diethiobutane.

Claims (2)

Process for the preparation of 1,4-dilithiobutane by reacting 1,4-dichlorobutane with lithium, characterized in that 1,4-dichlorobutane is reacted with lithium dispersed in an aromatic or saturated aliphatic hydrocarbon S or C7, preferably in benzene, the particle size of the lithium being it is in the range from 40 to 100 _(microns, with stirring and at a reaction temperature ranging from the boiling point of the hydrocarbon to a temperature up to 20 ° C lower, preferably at 75 to 85 ° C. 2. Process according to claim 1, characterized in that 1,4-dichlorobutane is dosed gradually, preferably until a stoichiometric ratio to lithium is reached.