DE1203282B - Process for the production of homogeneous liquid silicic acid esters - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

Number:
File number:
Registration date:
Display day:

C07f

German class: 12 q- 32/01

1203 282
U7606IVb / 12q November 25, 1960 October 21, 1965

Process for the production of homogeneous liquid silicic acid esters

Applicant:

Unilever N.V., Rotterdam (Netherlands) Representative:

Dr.-Ing. A. van der Werth, patent attorney, Hamburg-Harburg 1, Wilstorfer Str. 32

Named as inventor:

Harold Garton emblem,

Albert Keith Harrison, Grappenhall, Cheshire (Great Britain)

Claimed priority:
Great Britain November 27, 1959

(40478),

dated January 8, 1960 (749) -

The subject of German Auslegeschrift 1180 093 is the use of gel-forming silicic acid aminoalkyl esters as a binder for solid particles from which refractories are made, for example for the production of molds for casting metals. When using this will be the esters and the refractory particles to form mixed into a slurry, then shaped into the desired shape and hardened by the action of water. The water used to harden the binder can be included in the mixture; sometimes but atmospheric moisture can also fulfill this function. The gel-forming silicic acid aminoalkyl esters have compared to the usual silicic acid ester binders, e.g. B. Silicic acid ethyl ester, the Advantage that no gelling accelerator is required. As in the German Auslegeschrift mentioned above is described, the silicic acid aminoalkyl esters can by transesterification between silicic acid alkyl esters and amino alcohols are prepared, the alkyl groups of the esters in whole or in part be replaced by aminoalkyl groups.

If such transesterification processes are carried out between silicic acid ethyl esters (either ortho- or polysilicic acid esters) and the simple amino alcohols mono- 25 _

Ethanolamine and monoisopropanolamine felt through

homogeneous products are created, even if they remain. The only silicic acid aminoalkyl ester that uses an excess of either the ester or that presumably of the monoethanolamine and orthosilicate amino alcohol. The isopropyl proacid obtained is obtained but the silicic acid products have to be stored in closed containers for esters of the formula Si (OCH ₂ CH ₂ NH ₂ ) ₄ . Because pebbles are preserved, because they are easily miscible in the air with a skin acid propyl ester only partially miscible with the aminoalkyl in the result of gelation of the products by the atmospheric esters that form through transesterification between the humidity. these isopropyl silicic acid esters and monoethanol

It was also found that the silicic acid amine and monoisopropanolamine are obtained, but isopropyl ester, if they are subjected to a transesterification with 35, except when using small amounts of the amino monoethanolamine or monoisopropanolamine among alcohols, heterogeneous products are obtained,
be thrown, with the proportion of applied transesterification products, which are in two liquid

Amino alcohol, which is insufficient to separate all isopropyl phases, are unsatisfactory as a binder To replace groups of the ester, a product obtained for refractories because reproducible results which separates into two liquid layers. 40 extremely difficult to obtain and the If the released isopropyl alcohol doesn't wear off - use a solubilizer for the two

liquid phases is necessary. The use of solvents in silicic acid ester binders is however, seen as a disadvantage in foundry technology

Amount of amino alcohol still limited, see 45 because it mentions the mold making process makes the formation of heterogeneous products more difficult. Even in the presence of a homogenizing Solvents are formed from isopropyl silicates and monoethanolamine and monoisopropanolamine products received, other than those in

is distilled, the amount of amino alcohol that can be used in the reaction can be somewhat can be enlarged, but even then it is permissible

should be avoided.

This behavior of isopropyl silicates is obviously due to the fact that with

Monoethanolamine or monoisopropanolamine the 5 ° which the proportion of replaced isopropyl groups Formation of mixed esters, which is also very little isopropyl, easily skin in air and pyl groups such as aminoalkyl groups must be kept in locked containers

509 718/468

when they are not needed. This skin formation is undesirable and can eventually lead to complete hardening and uselessness of the products.

The invention relates to a process for the production of homogeneous liquid silicic acid esters, that show little or no tendency to form a skin in the presence of air or water vapor. The process is characterized in that an isopropyl polysilicate is used in a manner known per se or a mixture of such with isopropyl orthosilicate by heating with either

a) an amino alcohol or a mixture of several amino alcohols of the general formula

R ₃

CH ₃ - (CH ₂ ) _m - C - CH ₂ - OH
R ₁ -NR ₂

in which R ₁ and R _{2 are} hydrogen or methyl and m = 0 or 1, and R _{3 is} methyl when »2 = 0, and R _{3 is} hydrogen when» 2 = 1, or

b) a mixture of one or more of these amino alcohols and monoethanolamine and / or or monoisopropanolamine, the amount of the amino alcohols being that given above general formula is at least 0.25 mol per mol of the amino alcohol mixture,

transesterified until the end product contains about 0.1 to 1.0 aminoalkyl groups per silicon atom.

The transesterification is increased by heating the isopropyl silicate and the amino alcohols Temperatures carried out at reflux. The isopropyl alcohol released as transesterification progresses can be distilled off, the amount of which indicates the extent of the transesterification. Preferably the released alcohol is removed and the transesterification is carried out completely. The distance of the released isopropyl alcohol leads to products with an increased gel time.

Homogeneous products are made from mixtures of isopropyl esters of poly and orthosilicic acids, soft containing up to 50 percent by weight of orthoesters. But to preferred products with high To obtain silica content, silicic acid isopropyl ester are preferably implemented, which is less than contain about 20 percent by weight and in particular less than 10 percent by weight orthoesters.

The products obtained by the process of the invention gel when mixed with water, but not as quickly as those who are using appropriate amounts of monoethanolamine or Monoisopropanolamine aHein can be obtained as an amino alcohol component. From this it can be seen that the new products are ideally suited for use in foundries as binders for refractory materials are.

The following examples serve to illustrate the invention. Examples 1 to 16 and 19 to 22 illustrate method according to the invention. Examples 17 and 18 illustrate other methods for comparison.

For the production of the isopropyl polysilicate or isopropyl orthosilicate used as starting materials protection is not claimed.

For example

A mixture of 232.6 g of isopropyl alcohol and 17.3 ml of distilled water is slowly added to 170 g of silicon tetrachloride, the amount of water corresponding to 0.96 mol per mole of tetrachloride. Then the mixture is refluxed for 1 hour and left to stand overnight. 137.5 g of excess isopropyl alcohol are then ^{removed by distillation up to a temperature of 100 °} C., a practically neutral, crude isopropyl silicate with a silicon dioxide content of 38.05% remaining. The isopropyl orthosilicate content is 5.4%.

162 g isopropyl polysilicate and 0.2 mol

2-Amino-2-methyl-propan-l-ol are placed in a flask equipped with a fractionating column and a condenser heated so that the isopropyl alcohol can slowly distill off. In 2 hours the theoretical Amount of isopropyl alcohol distilled off. This gives a homogeneous product that can be exposed to air shows no skin formation. This product is referred to below as polysilicic acid ester A and contains about 0.2 aminoalkyl groups per silicon atom.

The following table explains the gelation process

hold the polysilicic acid ester A:

Volume of the
Polysilicic acid
esters A
in milliliters Volume of the
added water
in milliliters Gel time
in minutes 10
10
10
10 0.6
1.2
1.8
2.4 15th
10.5
10
10

Example 2

162 g of the isopropyl polysilicate prepared according to the procedure described in Example 1 and 0.25 mol of 2-amino-butan-l-ol are equipped with a fractionating column and condenser Flask heated so that the isopropyl alcohol can slowly distill off. In 3 hours the theoretical amount of isopropyl alcohol distilled off. This becomes homogeneous and none in the air Obtain skin-forming product. This product is referred to as polysilicic acid ester B in the following.

It contains about 0.25 aminoalkyl groups per silicon atom.

The gelation behavior of the polysilicic acid ester B is shown in the following table:

Volume of the
Polysilicic acid
esters B
in milliliters
fin Volume of the
added water
in milliliters Gel time
in minutes 10
10 2
1 4.5
4.5

Example 3

243 g of isopropyl polysilicate with a silicon dioxide content of 36.9% and an orthosilicic acid ester content of 8% and 133.5 g of 2-methyl-2-

5 6

amino-propan-l-ol become homogeneous in one with fractionation and does not show any skin formation in air,

The flask equipped with a column and a condenser is heated in such a way that 10 ml of this product are mixed with 2 ml

that the isopropyl alcohol slowly distilled off. After water, gelation occurs in 8 minutes.
2 hours of heating to a temperature of 130 ° C

and distilling off 50 g of isopropyl alcohol becomes the 5 examples
Temperature increased to 190 ⁰ C, and the reaction 162 g polysilicic acid isopropyl ester with a silicon participant for a further 2 hours at this temperature cium dioxide content of 36.9% and an orthosilicate content. The total weight of the acid ester content of 8% is then 87.2 g, corresponding to 0.1 mol of 2-amino-2-methyl-propan-1-ol, 0.05 mol Mo-97% of theory with a mixture of isopropyl alcohol distilled off . In this case, a homogeneous product is obtained and io noäthanolamin 0,05MoI monoisopropanolamine domestic product, the _n in air, a slight inclination i indicates a fractionating column and condenser with out supply to form a skin. This product is implemented in the armed flask. In about 2 hours the following is referred to as polysilicic acid ester C and theoretical amount (0.2 mol) of isopropyl alcohol contains about 1.0 aminoalkyl group per silicon atom. distilled, with a homogeneous reaction product

When mixing 10 ml of polysilicic acid ester C is obtained, which does not form a skin in the air. Of the

gelation occurs in 30 seconds with 2 ml of water. The silicon dioxide content of the product is 36.3%.

. . . When mixing 10 ml of the product with 2 ml

ΰ e ι s ρ ι e 1 4 water occurs in 10.5 minutes gelation. This

162 g polysilicic acid isopropyl ester with a SiIi product contains about 0.2 aminoalkyl groups per Si

ciumdioxydgehalt of 36.9% ^{a nd} a orthosilicic 20 liciumatom.

acid ester content of 8% ^and 2 mol of 2-dimethyl-. -to

Amino-2-methyl-propan-l-ol are shown in a similar manner

as implemented in Example 1. Here, a homo- 8100 g (50 mol) isopropyl polysilicate is used

Genetic and non-skinning product with a silicon dioxide content of 36.9% and a

obtain. The product contains about 0.2 aminoalkyl 25 orthosilicic acid ester content of 8%

groups per silicon atom. 305 g (5 mol) monoethanolamine and 445 g (5 mol)

When mixing 10 ml of this product with 2-amino-2-methyl-propan-l-ol in a fractionated

2 ml of water will gel in 90 minutes. nierkolonne and reflux condenser equipped flask

implemented. The implementation is in the example 5

Example _{5 30} carried out and the theoretical

9072 g of isopropyl polysilicate with an Si amount of isopropyl alcohol (600 g or 10 mol) ablicium dioxide content of 38.1% and an orthosilica distilled. The product is homogeneous, the acid ester content of 16.4% does not skin with 482 g of 2-Me air and has a silicon dioxide content of thyl-2-amino-propan-l-ol in a fractionating of 36.3% on. Upon mixing of 10 of the stirrer and Prokolonne ml flask equipped with 100-35 domestic product with 2 ml of water occurs in 13.5 minutes gelation 110 ⁰ C and reacted with a dry air flow a. This product contains about 0.2 aminoalkyl rate of 701 passed per hour. groups per silicon atom.
The heating and ventilation are interrupted if. .
the theoretical amount of isopropyl alcohol (283.5 g) B e 1 s ρ 1 e 1 IU
has been received. Before the determination of the gel 4 ° 7500 g of isopropyl polysilicate with an ensiling time, the product is left overnight with a silicon dioxide content of 36.9% and ortho-cooling. When mixing 10 ml of the product with a silicic acid ester content of 8%, 835 g with 2 ml of water will gel in 75 minutes. The 2-amino-2-methyl-propan-l-ol is implemented according to the procedure described in the game 5, which has a silicon dioxide content of 37.4%, where the product is homogeneous and does not form 45% of the theoretical amount of isopropyl alcohol in air (562 g) skin and contains about 0.1 aminoalkyl groups each is distilled off. The product is homogeneous, forms on silicon atom. the air no skin and has a silica. -if, content of 35% up. When 10 ml of the Example 6 product is mixed with 2 ml of water, gelation occurs in 14 minutes

The product obtained according to Example 5 is 5 °. This product contains approximately 0.2 aminoalkyl

a further 453.6 g of 2-methyl-2-aminopropane-l-ol traction groups per silicon atom.

and, as described in Example 5, others. .

283.5 g of isopropyl alcohol are distilled off. One SiIi- B e 1 s ρ 1 e 1 e 11 to 18

Conversion of 162 g (1 mol) of isopropyl polysilicate with cium dioxide content of 36.8%

tion product is homogeneous and does not form in air with a silicon dioxide content of 36.9% and a

Skin and contains about 0.2 aminoalkyl groups per Si-orthosilicic acid ester content of 5.2% are used

liciumatom. When mixing 10 ml of this different mixture of 2-amino-2-methyl-pro

Product with 2 ml of water occurs in 25 minutes, gepan-l-ol and monoethanolamine as well as with various

lation a. NEN mixtures of 2-amino-2-methyl-propan-l-ol

. 6o and monoisopropanolamine implemented, as in the individual

Example 7 _nen ^ _n ^ _QJ . f _{o s} ig _{(j s} chart. The mixture

To the degree of substitution of the silicic acid ester and amino alcohols according to Example 6 is before the

Asked product to 0.3 aminoalkyl groups per reaction heterogeneous. Implementation is through

To increase silicon atom, 335 g (2 moles) of this 1 hour refluxing of the mixture will result carried out with 18 g (0.2 mol) of 2-amino-2-methyl-propane 65 conditions, the released iso-

l-ol implemented, whereby the thoeretic amount of isopropyl alcohol is not removed,

propyl alcohol by heating the mixture to Examples 17 and 18 are comparative and

12O ⁰ C is distilled off. The product obtained is refine the properties of the products obtained,

by similarly isopropyl polysilicate and monoethanolamine and monoisopropanolamine implemented. The gel times are

determined by mixing 10 ml of the reaction product with 2 ml of water. Each of the products contains about 0.2 aminoalkyl groups per silicon atom.

example Manufacturing properties Gelling
time in
Minutes 11 Polysilicic acid isopropyl ester (1 mol)
+ 0.1 mole monoethanolamine and
0.1 mole of 2-amino-2-methyl-propan-1-ol clear, no skin formation
the air 6.5 12th Polysilicic acid isopropyl ester (1 mol)
+ 0.05 mol monoethanolamine and
0.15 moles of 2-amino-2-methyl-propan-1-ol clear, no skin formation
the air 10 13th Polysilicic acid isopropyl ester (1 mol)
+ 0.15 mol monoethanolamine and
0.05 moles of 2-amino-2-methyl-propan-1-ol clear, very little tendency to
Skin formation in the air 6th 14th Polysilicic acid isopropyl ester (1 mol)
+ 0.1 mol monoisopropanolamine and
0.1 mole of 2-amino-2-methyl-propan-1-ol clear, no skin formation
the air 7th 15th Polysilicic acid isopropyl ester (1 mol)
+ 0.05 mol monoisopropanolamine and
0.15 moles of 2-amino-2-methyl-propan-1-ol clear, no skin formation
the air 7th 16 Polysilicic acid isopropyl ester (1 mol)
+ 0.15 mol monoisopropanolamine and
0.05 moles of 2-amino-2-methyl-propan-1-ol clear, no skin formation
the air 5 17th Polysilicic acid isopropyl ester (1 mol)
4- 0.2 moles of monoethanolamine clouded, rapid skin formation
in the air 3.5 18th Polysilicic acid isopropyl ester (1 mol)
+ 0.2 mole monoisopropanolamine clear, rapid skin formation
the air. 3

By reacting in a similar manner isopropyl polysilicate and 0.3 mol of monoisopropanolamine again, the liberated isopropyl alcohol is not removed, becomes a clear product obtain. The gelation time of a mixture of this product (10 ml) and water (1 ml) is 20 seconds. However, if more than 0.3 mol of amino alcohol is used, a heterogeneous product will be obtained obtain.

Example 19

45

162 g of isopropyl polysilicate with a silicon dioxide content of 37% ^UI * d an orthosilicic acid ester content of 7% are reacted with a mixture of 0.1 mol of 2-amino-butan-1-ol and 0.1 mol of monoethanolamine, the theoretical amount of isopropyl alcohol being distilled off will. The product is slightly cloudy, homogeneous and does not skin in the air. When 10 ml of this product is mixed with 2 ml of water, gelation occurs in 13.25 minutes. The product contains about 0.2 aminoalkyl groups per silicon atom.

Example 20

162 g of isopropyl polysilicate with a silicon dioxide content of 37% and an orthosilicic acid ester content of 7% with a mixture of 0.15 mol of 2-dimethylamino-2-methlypropan-l-ol and 0.15 mol of monoethanolamine reacted, the theoretical amount of isopropyl alcohol being released will. The product is slightly cloudy, homogeneous and does not skin in the air. When mixing 10 ml of this product with 2 ml of water will gel in 4.75 minutes. The product contains about 0.3 aminoalkyl groups per silicon atom.

Example 21

180 g of a mixture of isopropyl orthosilicate and isopropyl polysilica, the Mixture has a silicon dioxide content of 33.2% »an orthosilicic acid ester content of 30% and contains 1 mol of silicon dioxide are reacted with 26.7 g (0.3 mol) of 2-amino-2-methylpropan-l-ol, the theoretical amount of isopropyl alcohol being released. The reaction product is clear, homogeneous and does not skin when exposed to air. It contains 0.3 aminoalkyl groups per silicon atom.

When 10 ml of the reaction product are mixed with 2.5 ml of water, gelation occurs in 5.5 minutes a.

Example 22

200 g of a mixture of isopropyl orthosilicate and isopropyl polysilicate, the mixture having a silicon dioxide content of 22.7% Orthosilicic acid ester content of 50% and containing 1 mole of silicon dioxide are 27.6 g (0.3 mol) of 2-amino-2-methylpropan-l-ol reacted, the theoretical amount of isopropyl alcohol being released will. The reaction product is clear, homogeneous and does not form a skin in the air. It contains 0.3 aminoalkyl groups per silicon atom.

When 10 ml of the reaction product is mixed with 2 ml of water, gelation occurs in 10 minutes a.

Claims (1)

Claim: Process for the production of homogeneous liquid silicic acid esters, characterized in that, that in a manner known per se, an isopropyl polysilicate or a mixture one with isopropyl orthosilicate by heating either with a) an amino alcohol or a mixture of several amino alcohols of the general formula T " CH ₃ - (CH ₂ V - C - CH ₂ - OH
R ₁ -NR ₂ 10 10 in which R ₁ and R _{2 are} hydrogen or methyl and m = 0 or 1, and R _{3 is} methyl when / n = 0, and R _{3 is} hydrogen when m = 1, or b) a mixture of one or more of these amino alcohols and monoethanolamine and / or. or monoisopropanolamine, the amount of the amino alcohols of the above given general formula at least 0.25 mol per mol of the amino alcohol mixture amounts to, transesterified until the end product has about 0.1 to 1.0 aminoalkyl groups contains per silicon atom.