The carboxyl group-containing acrylic esters of the general formula below are useful compounds for many applications : Z is a bivalent organic radical as a linker for the two given functional groups. The nature of the bridging group or linker Z of a compound of general formula (1) should preferable correspond to the intended use of a given compound of formula (1). For example with regard to LCD applications, there is a need to have compounds of general formula (1), wherein Z denotes a backbone having both a flexible and a rigid part. Accordingly such compounds might be represented by general formula (11) : In formula (II) A denotes a divalent flexible spacer group, Y a divalent linking group and M a divalent rigid group containing up to 30 carbon atoms. To provide the intended rigidity, the group M is a hydrocarbon ring (s) and/or heterocyclic ring (s) containing group.

Some compounds of general formula (11), e. g. compound 1 below with CAS No. 83883-26-5, 1 [83883-26-5] show liquid crystalline properties and can be polymerized to give liquid crystal polymers.

They are also important intermediates for the synthesis of polymerizable liquid crystal compounds. These liquid crystal compounds can be oriented by known techniques and the orientation fixed by means of polymerisation of the acrylic groups. Thus stable, crosslinked polymer layers exhibiting anisotropic mechanical, optical, electrical and magnetic properties are obtained which have broad applications e. g. in optical data storage, displays, decorative coatings, security elements, coating for optical films etc.

In the literature two direct synthetic routes to prepare compounds of general formula (II) are described: The first route is by way of the reaction of a carboxyl group-containing alcohol with acrylic acid and concomitant removal of the water formed according to reaction scheme (A) and exemplified for a compound of general formula (II) by compound (1) below : The main drawback of reaction (A) is that a big molar excess of acrylic acid (b) (usually about 8-10 times molar excess) has to be used in order to minimize the formation of by-products.

These are mainly dimers and oligomers from the self esterification reaction of both the alcohol and the carboxylic group of (a1) as well as secondary products from the known addition of acrylic acid (b) to the double bond of (1).

Even using a big excess of acrylic acid, yields and purity of the products (1) are not satisfactory-particularly for LCD applications, where high purity products are demanded.

Moreover isolation of the product of formula (1) is severely handicapped as at the end of the reaction the big excess of acrylic acid has to be removed, usually by repeated washing of the reaction mixture with water. The water phases containing the excess acrylic acid represent a potential chemical hazard due to their tendency towards spontaneous polymerisation and they have to be correctly disposed of, as the regeneration of acrylic acid is not economic.

This greatly adds to the costs of the process.

The first citation of above mentioned compound (1) can be found in Ringsdorf et al., Makromol. Chem. 183,2311-2321 (1982), wherein the reaction of the corresponding alcohol using acrylic acid (8x molar excess) and p-toluenesulfonic acid as catalyst, with azeotropic removal of water, is described (see also reaction scheme (A) above). The yield for compound (1) is given with 64%.

The second route for the preparation of a compound (1) is by way of the reaction of a carboxyl group-containing alcohol (a1) with acryloyl chloride (c) and a base such as triethylamine according to reaction scheme (B) below : No big excess of acryloyl chloride (c) is normally necessary but the HCI formed has to be removed, or else chlorine containing by-products are formed, stemming from HCI addition to the acrylic double bond. The removal or inactivation of HCI is usually effected via addition of stoichiometric amounts of amines, such as triethylamine or dimethylaniline, which leads to formation of the corresponding hydrochloride salts.

D. Broer et al., Makromol. Chem. 190,2255-2268 (1989) describes the synthesis of compound 1 of general formula (I) using acryloyl chloride and dimethylaniline in dioxane at 60°C without indicating yield and purity, however DE 196 43 048 A1 states a yield for compound (1) of 75%, using the same conditions as D. Broer et al.

US 6,258, 974 B1 describes the synthesis of compound (1) using acryloyl chloride as being troublesome, giving rise to hydrochlorinated impurities. The amount is also dependent on the solvent. If THF is used with a base the product contains 8-10% impurity, in chloroform with a base it is 0-4% (with only 48% yield) and in THF without a base the impurity amounts to 20-25%. Clearly the absence of the base is shown to be detrimental to the reaction.

JP 2002-037759 A describes the synthesis of acrylic acid esters of general formula (II) and their methacrylic analogues. The process consists of the following steps: First, in situ generation (without isolation) of (meth) acryloyl chloride (c) from the corresponding acids in a solvent, e. g. THF. Second, reacting the alcohol (a) with the in situ generated acid chloride, whereby a second solvent, such as dimethylacetamide, is added. Third, treating the reaction product with a base such as triethylamine or dimethylaniline to eliminate HCI from the halogenated by-product (which amounts to-32% (HPLC) ), converting it back to the acrylic ester. Also here the absence of an added base leads to a substantial amount of halogenated by-product.

The known methods for the acylation of compounds of general formula (II), e. g. compound (1), are troublesome and prone to give low yields and/or to creation of various by-products.

Either reaction with an excess acrylic acid under azeotropic removal of water or reaction with acryloyl chloride and a base, such as triethylamine or dimethylaniline, in a solvent are used.

If acryloyl chloride is used without base substantial amounts of halogenated by-products are formed.

However, high yield and purity of products according to general formula (II) are important factors when aiming for a commercial production process. Also production costs are strongly dependent on time needed for the reaction and the isolation of the product. A complex reaction set up, involving e. g. a variety of material transfers and a lengthy isolation procedure greatly add to the cost of production.

Now, the instant invention provides a new, improved process for the production of acrylic esters of general formula (II) from hydroxy compounds in very high yield and purity. The new process also utilizes acryloyl chloride as the acrylating reagent but without an added base.

Surprisingly, this has been achieved by using some special solvents and control of the reaction temperature.

Accordingly, a first aspect of the instant invention is a process for the production of acrylic esters of general formula (II) by way of reacting a carboxyl group containing hydroxy compound of general formula (a) with acryloyl chloride (c) according to the following general scheme (C): wherein A denotes a flexible spacer group, Y a divalent linking group and M a hydrocarbon ring (s) and/or heterocyclic ring (s) containing rigid group containing up to 30 C atoms, characterized in that the reaction is carried out a) in the presence of a solvent medium, whereby of the solvent medium contains at least 30% per weight based on the total amount of the solvent medium of a solvent selected from the group of N, N-Dimethyl acetamide (DMAc), N-Methyl-pyrrolidon (NMP), N, N, N'N'-Tetramethyl urea (TMU) and N-Methylcaprolactam, b) in the absence of a base, and that c) the reaction temperature is kept between-10°C and +50°C.

Under said reaction conditions the carboxyl group-containing alcohol (a) reacts selectively at the hydroxyl group with acryloyl chloride (c) to give the carboxyl group-containing containing acrylic ester of general formula (II) in very high yield and purity. Practically no by-products, which would reduce yield and purity, are formed.

Surprisingly, this is not the case with methacryloyl chloride. While methacryloyl chloride also reacts under said conditions, the reaction is less clean and some by-products are formed.

The reaction conditions are simple and straightforward. The following reaction parameters are important and have to be fulfilled : The reaction temperature is a critical parameter. By-products are formed if it is too high. As the reaction proceeds at a fast rate at room temperature high temperatures are not needed.

The temperature should be kept between the limits of-10° and +50°C.

Preferred is a range between the limits of-5° and +45°C, more preferable is a range between the limits of 0° and +35°C, and the most preferred range is between the limits of 5°C and 30°C.

A solvent medium has to be used. It must contain at least one of the following polar aprotic solvents : N, N-Dimethyl acetamide (DMAc), N-Methyl-pyrrolidon (NMP), N, N, N'N'-Tetramethyl urea (TMU) and N-Methylcaprolactam.

Surprisingly, the similar solvents Dimethyl formamide (DMF) and Dimethyl sulfoxyde (DMSO) are both not suitable, as either by-products are formed (DMF) or the reaction does not proceed in the right direction (DMSO). Preferred solvents are N, N-Dimethyl acetamide (DMAc) and N-Methyl-pyrrolidon (NMP), the latter is the especially preferred solvent.

The solvent medium must either be 100% of a solvent selected from one or more than one of the above four mentioned solvents, or it can be a solvent mixture consisting of at least 30 wt% of one or more than one of the four solvents with a solvent. The solvent can be chosen from a large group of organic solvents known. The solvent should not be reactive with acryloyl chloride in the given temperature range, which means it should not contain functional groups which are known to react with acid chlorides, e. g. hydroxyl groups or acid groups. The amount of solvent in the solvent medium can vary over a broad range of about 0-70 wt%, depending on the type of solvent, the reaction conditions and the reactant (a). In general the amount should be chosen such that the reaction proceeds without the formation of the chlorine containing by-products. Preferably the solvent is water miscible, so that the reaction product can be easily isolated by precipitation in water.

Examples of cosolvens are: tetrahydrofurane, acetonitrile, acetone, toluene etc.

Equimolar amounts of acryloyl chloride (c) or a slight excess of preferably from 1.05 to 1.4 mol of acryloyl chloride (c) per 1.0 mol of alcohol (a) is used. If less acryloyl chloride is used, some of the alcohol remains unreacted. Small amounts of water in the solvent will lead to the hydrolysis of a corresponding amount of acryloyl chloride, but by using an excess this loss can be compensated.

No base, such as triethylamine or dimethylaniline, is necessary.

The start concentration of the carboxyl group containing hydroxy compound of general formula (a) in the reaction mixture can vary widely, e. g. 5-60% per weight, based on the sum of compound (a) and the solvent medium. Preferably the start concentration for (a) is from 10-40% per weight. Especially preferable a start concentration for (a) is from 25- 35% per weight. Accordingly, the solvent media can vary from 95-40, preferably from 90 to 60, especially preferably from 75-65% per weight. It is largely determined by practical and economical considerations, such as e. g. viscosity of the reaction mixture, solubility of the alcohol (a) and maximum volume yield.

The reaction product of general formula (II) can be conveniently isolated by diluting the reaction mixture with water and separating the aqueous phase, containing the solvent and HCI, from the usually solid product phase. The carboxyl group-containing alcohols (a) being used for the inventive process reaction according the reaction scheme (C) are compounds, wherein A denotes a flexible spacer group, Y a divalent linking group and M a divalent hydrocarbon ring (s) and/or heterocyclic ring (s) containing rigid group containing up to 30 C atoms.

Examples for a flexible spacer A are groups selected from: - [-CHn-, and- [-CH2CH (R)-0-] m- [-CH2] n-, wherein n = 2-20, m = 1-5, and R =-H or-CH3.

Preferable spacers A are groups- [-CH2] n-, wherein n = 2-12, preferably n = 6.

The divalent linking group Y is a group selected from: The preferred linking group Y is-O-.

The group M is a divalent group consisting of at least one cyclic and possibly substituted saturated or unsaturated hydrocarbon or heterocyclic ring. One linkage of group M is bound directly to the linker group A, while the other linkage of group M is either a direct bond or a bridge to the carboxyl group. Said bridge is a short unsaturated alkenyl-or alkinyl group. The overall group M, that is the basic ring structure including possible substituents and a possible bridge to the carboxyl group, can contain up to 30 carbon atoms, preferably up to 20 carbon atoms, more preferably M is a group comprising between 6 and 14 carbon atoms.

Heterocyclic means that the ring contains one to three heteroatoms, being usually either N and/or O and/or S. Possible substituents are the Halogen atoms F, Cl, or Br, preferably F, a linear or branched C, to Ce alkyl, alkenyl or alkinyl group, a Ci to C6 alkoxy group, a nitrile (CN) group. If the group M consists of more than one ring, those rings can be bonded via a direct bond or via a saturated or unsaturated hydrocarbon bridge, or two or more than two rings are annelated rings. Some non-limiting examples for a possible group M, whereby each - H bound to a given carbon ring atom could be thought of as possibly being replaced by one of the substituents as defined above, are shown below : Preferred groups M are those which contain only one or two unsaturated ring (s), and more preferably those groups M contain only hydrocarbon ring (s), and even more preferably those groups M are unsubstituted rings. Especially preferred unsubstituted groups M are: The most preferred group M is benzene.

Accordingly especially preferred compounds of general formula (II) are the following ones: The most preferred compound is: 1 [83883-26-5] The carboxyl group-containing alcohols (a) described above, can be obtained by various known methods. For example products like compound (a1) can be made by an etherification of the phenolic hydroxyl group of the benzoic acid residue with an a, w-hydroxy chloro (or bromo) alkane according to the method described in M. Portugal, H. Ringsdorf, R. Zentel, Makromol. Chem. 183,2311-2321 (1982).

As already mentioned it is possible to obtain carboxyl group-containing acrylic esters of general formula (il) in a high yield of at least 80% and a purity grade of at least 95%.

Practically no by-products, which would reduce yield and purity, are observed. By working strictly within the above described working conditions it is possible to obtain products having a grade of purity of at least 97% and up to 99% as determined by HPLC analysis (area%).

The obtained yields are at least 80% and normally well above 90% of theory. Those aspects, together with its economic advantages, makes the inventive process especially suitable for obtaining products useful particularly for LCD applications in an industrial scale.

The invention is illustrated by the following non-limiting examples: Example 1 (E 1); Synthesis of compound 1: In a 30 litre chemical reactor are dissolved 4766.00 g (purity-100%, 20.00 mol) of 4- (6- hydroxyhexyloxy) benzoic acid (preparation e. g. M. Portugal, H. Ringsdorf, R. Zentel, Makromol. Chem. 183,2311-2321 (1982) ) and 2.91 g phenothiazin (polymerisation inhibitor) in 10'000 mi of N-methyl pyrrolidone at ca. 20°C. To the clear, stirred solution 2074 g of acryloyl chloride (Aldrich, 96%, 22 mol) are gradually added, keeping the reaction temperature below 30°C by external cooling. After the addition, which takes about 1 hour, the reaction mixture is stirred for 2 hours at 25°C, when TLC analysis (Silicagel, Cydohexane: Ethylacetate : Acetic acid = 50: 50: 2, parts b. volume, UV fluorescence indicator) indicates completion of the reaction. A yellowish suspension is formed. It is gradually precipitated into 33'000 ml of water using a high speed stirrer (1300 rpm) and keeping the temperature below 25°C. After finishing the addition, the suspension is stirred for 1/2 hour and filtered. The filter residue is washed twice with 5000 ml of warm (-40°C) water and redispersed in 33'000 ml of warm water for 1/2 hour, filtered and the residue washed twice with 5000 ml of warm water.

The moist residue is added to 20'000 ml of toluene, 2.93 g of di-tert. butyl-p-cresole (BHT, polymerisation inhibitor) are added and the mixture heated to 65°C to dissolve. A slightly coloured emulsion of some water in toluene results. The water phase is separated off and to the toluene solution is added 150.00 g of Bleicherde Tonsil Standard 312 ff (Fullers earth, Achenbach Buschhutten GmbH, D-57223 Kreuztal, Germany) and 150.00 g of Hyflo (diatomaceous earth, Mansville Corp. ) and the suspension stirred for 1/2hour at 65°C. The suspension is filtered and the clear filtrate cooled to 0°C and kept for several hours to crystallize the product, which is filtered off and dried in vacuum at T = 35°C.

5383.60 g (92% o. th. ) of colourless, crystalline 4-(6-acryloyloxyhexyloxy) benzoic acid = compound (1) is obtained.

Analytical Data: HPLC purity (area%) = 99%, peak maximum at 8.188 min. Conditions: Column 250 x 4.6 mm, Nucleosil ds 5 pm UV Detection 254 nm Timetable (min) % Acetonitrile % H20 + 0.04% TFA (*) Flow (ml/min) 00.00 60 40 1 5.00 60 40 1 20.00 95 5 1 30.00 95 5 1 Stoptime 35.00 60 40 1 ° TFA = Trifluor acetic acid Elemental Analysis calc. found % C 65.74 65.83 % H 6.90 6.81 % O 27.37 27.32 % ci 0.0 0.16 DSC Analysis, Dynamic run, T = 30°-150°C, heating rate = 2°C/min melting point = 92°C ; clearing point = 111 °C Example 2 (E 2); synthesis of compound 1: Example 1 is repeated, but instead of allowing a temperature of <30°C during the addition of the acryloyl chloride, the temperature this time is kept below 15°C during said addition by additional external cooling. After the addition the mixture is stirred for 6 hours at 10°C. The product isolation procedure is the same as described in example 1.

5506.70 g (94% o. th.) of colourless, crystalline 4- (6-acryloyloxyhexyloxy) benzoic acid = compound (1) is obtained.

Analytical Data: HPLC purity (area%) = 99.2 %, peak maximum at 8.188 min. Conditions: Column 250 x 4.6 mm, Nucleosil C18 5 um UV Detection 254 nm Timetable (min) % Acetonitrile % H20 + 0.04% TFA Flow (ml/min) 00.00 60 40 1 5.00 60 40 1 20.00 95 5 1 30. 00 95 5 1 Stoptime 35. 00 60 40 1 Elemental Analysis calc. found % C 65.74 65.65 % H 6.90 6.55 % O 27.37 27.31 % ci 0.0 0.20 DSC Analysis, Dynamic, T = 30°-150°C, heating rate = 2°C/min, melting point = 92. 6°C ; clearing point = 110. 9°C Inventive (E 3-E 10) and comparative (CE 1-CE 8) Examples : synthesis of compound 1: The reactions are conducted according to the procedure given in detail for Example 3.

Example 3 (E 3) ; synthesis of compound 1: In a 250 ml chemical reactor are dissolved 23.89 g (0.10 mol) of 4- (6-hydroxyhexyloxy) benzoic acid (purity-100%, preparation e. g. literature mentioned in example 1) in 100 g of dimethyl- acetamide at ca. 20°C. To the dear, stirred solution are gradually added 10.26 g (0.11 mol) of acryloyl chloride (Aldrich 96%), keeping the reaction temperature below 35°C by external cooling. After the addition, which takes about 15 minutes, the reaction mixture is stirred for 1 hours at 30°C, when TLC analysis (Silicagel, Cyclohexane : Ethylacetate : Acetic acid = 50: 50: 2, parts b. volume, UV fluorescence indicator) indicates completion of the reaction. A nearly colourless suspension is formed. It is gradually precipitated into 400 ml of cold water using a high speed stirrer (1300 rpm). After finishing the addition, the suspension is stirred for ½hour and filtered. The filter residue is washed twice with warm (-40°C) water (400 ml), filtered and the residue dried in vacuo at 25°C. The thus obtained colourless, crystalline solid is dissolved in 93.40 g toluene at 70°C, 0.14 9 of di-tert. butyl-p-cresole (BHT, polymerisation inhibitor) added and the solution cooled slowly to 0°C. The crystalline precipitate is filtered off and dried in vacuum at 35°C to constant weight. 24.40 g (83.5% o. th. ) of colourless, crystalline 4- (6-acryloyloxyhexyloxy) benzoic acid = compound (1) are obtained.

Analytical Data: HPLC purity (area%) = 98.15%, peak at 8.129 min. Conditions: Column 250 x 4.6 mm, Nucleosil C, 8 5 pm UV Detection 254 nm Timetable (min) % Acetonitrile % H20 + 0.04% TFA Flow (ml/min) 00.00 60 40 1 5.00 60 40 1 20. 00 95 5 1 30. 00 95 5 1 Stoptime 35.00 60 40 1 The following table 1 depicts the results obtained in the synthesis of compound 1 by altering the reaction conditions of example 3. Experiments conducted outside the conditions of the present invention are called"Comparative Examples" (CE).

Table 1 (Part @, Inventive Examples) : E3 E4 E5 E6 Solvent DMAc TMU NMC NMP Acryloylchloride mol% 110 140 110 110 Temperature °C 25-36 25-40 25-40-5 Yield % #100 86 n. d. n. d. HPLC (area%) product 1 8.1 min 97.60 97.20 98.30 96.70 () by-product 8.3 min none very little none none Elemental Analysis n. d. n. d. n. d. % C 65.74 C 64. 83 % H 6.90 H 6. 81 % O 27.37 O 26. 95 % ci 0 Cl 1.21 E7 E8 E9 E10 Solvent NMP: NMP: THF NMP: NMP: Acetonitrile = 1 : 1 Toluene Acetone = 1 : 1 = 1 : 1 = 1 : 1 Acryloylchloride mol% 110 110 110 110 Temperature °C 25 25-40 25-40 0-5 Yield % 89 n.d. 95 89. 6 HPLC (area%) product 1 8.1 min 99.00 99.00 98.10 98.10 ) by-product 8.3 min none none very little none Elemental Analysis n. d. n. d. % C 65.74 C 65. 55 C 65. 21 % H 6.90 H 6. 90 H 6. 89 % O 27.37 O 27. 46 O 27. 29 % ci 0 Cl 0. 30 Cl 0.46 Table 1 (Part II, Comparative Examples) : CE 1 CE 2 CE 3 Solvent DMF DMSO NMP Acryloylchloride mol% 110 110 110 Temperature °C 25-30 25-40 80 Yield % n. d. n. d. n. d. HPLC (area%) product 1 8.1 min 44 no product 81.60 t) by-product 8.3 min many impur. many impur. 14.80 Elemental Analysis n. d. % C 65.74 % H 6.90 % O 27.37 % CI 0 CE 4 CE 5 CE 6 Solvent Acetonitrile THF NMP: Acetonitrile = 1: 9 Acryloylchloride mot% 110 110 110 Temperature °C 25-40 25-40 25-40 Yield % n. d. n. d. n. d. HPLC (area%) product 1 8.1 min no product 67.10 56.30 () by-product 8.3 min many impur. 27.50 32.20 Elemental Analysis n. d. n. d. % C 65.74 % H 6.90 % O 27.37 % CI 0 Used solvents and their abbreviations: N, N-Dimethyl acetamide (DMAc), N-Methyl-pyrrolidon (NMP), N, N, N'N'-Tetramethyl urea (TMU), N-Methylcaprolactam (NMC), Dimethyl formamide (DMF), Dimethyl sulfoxyde (DMSO), Tetrahydrofurane (THF).

Experiments E 3-E 5 show that DMAc, TMU and NMC can be used as alternatives to NMP.

In the case of TMU, the solvent was not dry and contained some water; therefore an excess had to be added of acryloyl chloride (140 mol%) to bring the reaction to completion. In E 6 a reaction temperature of-5°C has successfully been used. Experiments E 7-E 10 demonstrate the usefulness of mixtures of the inventive polar aprotic solvents with suitable cosolvents.

Comparative Examples CE 1 and CE 2 reveal that DMF and DMSO, which are non-inventive polar aprotic solvents, do not work. DMF leads to a yield of Product (1) of only 44% with several by-products, whereas in DMSO the reaction seems to take another direction and practically no product could be detected.

In CE 3 a reaction temperature of 80°C is applied, resulting in a higher fraction of the impurity at 8.3 min. (HPLC).

In CE 4-CE 5 solvents outside the claims of the invention are used. This leads to either no product at all or in the case of THF to low product yield.

CE 6 is been done with a solvent mixture in inappropriate proportions, giving lower product yield and higher fractions of by-products.

Example 11 (E 11) ; synthesis of compound 2: In a 250 ml chemical reactor are dissolved 79.90 g (purity~100%, 0.30 mol) of4- (8- hydroxyoctyloxy) benzoic acid (preparation e. g. M. Ukon et al, Macromolecular Materials and Engineering 287 (10), 698-705 (2002) ) in 150 g of N-methyl pyrrolidone at ca. 35°C. To the clear, stirred solution are gradually added 31.11 g of acryloyl chloride (Aldrich, 96%, 0.33 mol), keeping the reaction temperature below 32°C by external cooling. After the addition, which takes about 15 minutes, the reaction mixture is stirred for 1 hour at 30°C, when TLC analysis (Silicagel, Cyclohexane : Ethylacetate : Acetic acid = 50: 50: 2, parts b. volume, UV fluorescence indicator) indicates completion of the reaction. A white suspension is formed. It is gradually precipitated into 500 ml of water using a high speed stirrer (1300 rpm) and keeping the temperature below 25°C. After finishing the addition, the suspension is stirred for 1/2 hour and filtered. The filter residue is washed twice with 200 ml of warm (-40°C) water and redispersed in 500 ml of warm water for 1/2 hour, filtered and the residue washed twice with 200 ml of warm water and dried in vacuum at T = 35°C to constant weight. 94. 60 g (98% o. th.) of colourless, crystalline 4- (8-acryloyloxyoctyloxy) benzoic acid = compound 2 is obtained.

Analytical Data: HPLC purity (area%) = 96.1%, peak maximum at 2.1 min. Conditions: Column 125 x 4.6 mm, Nucleosil Cis 5 pm UV Detection 254 nm Timetable (min) % Acetonitrile % H20 Flow (ml/min) 00.00 90 10 1 Stoptime 8.00 90 10 1 Elemental Analysis calc. found % C 67.48 67.26 % H 7.55 7.32 % 0 24.97 24.89 % Ci 0.0 0.49 DSC Analysis, Dynamic, T = 30°-150°C, heating rate = 2°C/min, melting point = 81. 6°C.

Example 12 (E 12); synthesis of compound 3: In a 250 ml chemical reactor are dissolved 52.06 g (purity-100%, 0.25 mol) of 4- (2- hydroxyethyloxy) cinnamic acid (preparation US 6,461, 694 B1) in 126 g of N-methyl pyrrolidone at ca. 20°C. To the clear, stirred solution are gradually added 25.66 g of acryloyl chloride (Fluka, 97%, 0.275 mol), keeping the reaction temperature below 35°C by external cooling. After the addition, which takes about 15 minutes, the reaction mixture is stirred for 1 hour at 35°C, when TLC analysis (Silicagel, Cyclohexane : Ethylacetate : Acetic acid = 50 : 50: 2, parts b. volume, UV fluorescence indicator) indicates practically completion of the reaction. A white suspension is formed. It is gradually precipitated into 500 ml of water using a high speed stirrer (1300 rpm) and keeping the temperature below 25°C. After finishing the addition, the suspension is stirred for 1/2hour and filtered. The filter residue is washed twice with 200 ml of warm (-40°C) water and redispersed in 500 ml of warm water for 1/2 hour, filtered and the residue washed twice with 200 ml of warm water and dried in vacuum at T = 35°C to constant weight. 64.73 g (98.7% o. th. ) of colourless, crystalline 4- (2- acryloyloxyethyloxy) benzoic acid = compound 3 is obtained.

Analytical Data: HPLC purity (area%) = 97. 51 %, peak at 4.73 min, Conditions: Column 250 x 4.6 mm, Nucleosil C18 5 pm UV Detection 254 nm Timetable (min) % Acetonitrile % H20 + 0.04% TFA Flow (ml/min) 00.00 60 40 1 5.00 60 40 1 20.00 95 5 1 30. 00 95 1 Stoptime60401 Elemental Analysis calc. found % C 64.12 63.92 % H 5.38 5. 43 % O 30.50 30.38 % CI 0. 0 0. 44 DSC Analysis, Dynamic, T = 30°-250°C, heating rate = 2°C/min melting point = 186°C, with start of polymerisation.

Example 13 (E 13) ; synthesis of compound 4: In a 1500 ml chemical reactor are dissolved 469.90 g (purity-90%, 1.60 mol) of 4- (6-hydroxy- hexyloxy) cinnamic acid (preparation e. g. Th. Koch et al., Makromol. Chem. 190,1369-77 (1989) and 0.24 g phenothiazin (polymerisation inhibitor) in 1600 g of N-methyl pyrrolidone at ca. 60°C. The solution is cooled to 20°C and 165.94 g of acryloyl chloride (Fluka, 96%, 1.76 mol) are gradually added under stirring, keeping the reaction temperature at 20°C by external cooling. After the addition, which takes about 60 minutes, the reaction mixture is stirred for 1 hour at 20°C, when TLC analysis (Silicagel, Cyclohexane : Ethylacetate : Acetic acid = 50: 50: 2, parts b. volume, UV fluorescence indicator) indicates that there is still a small amount of starting material left. An additional 16.50 g of acryloyl chloride is added and the mixture stirred for a further 30 min. at 20°C. The white suspension is gradually precipitated into 5300 ml of water using a high speed stirrer (1300 rpm) and keeping the temperature below 25°C.

After finishing the addition, the suspension is stirred for 1/2 hour and filtered. The filter residue is washed twice with 400 ml of warm (-40°C) water and redispersed in 2640 ml of warm water for /2 hour, filtered and the residue washed twice with 400 ml of warm water.

The moist residue is added to a mixture of 1800 g of toluene and 1000 g of ethyl acetate, 0.23 g of di-tert. butyl-p-cresole (BHT, polymerisation inhibitor) is added and the mixture heated to 65°C to dissolve. A slightly coloured emulsion of some water in toluene results.

The water phase is separated off and the slightly turbid organic solution cooled to 0°C and kept for several hours to crystallize the product, which is filtered off and dried in vacuum at T = 35°C. 478.20 g (94% of th.) of the product with a HPLC purity of 95.8% is obtained. It is recrystallized from 2390 g ethyl acetate (65°C) to give 457.20 g (89.7% of th.) of colourless product.

Analytical Data: HPLC purity (area%) = 98. 80%, peak at 9.416 min, Conditions: Column 250 x 4.6 mm, Nucleosil C1 5 nom UV Detection 254 nm Timetable (min) % Acetonitrile % H20 + 0.04% TFA Flow (ml/min) 00.00 60 40 1 5.00 60 40 1 20. 00 95 5 1 30. 00 95 5 1 Stoptime 60 40 1 Elemental Analvsis calc. found % C 67.91 67.95 % H 6.97 7.04 % ci 0.0 0.085 DSC Analvsis, Dynamic, T = 30°-150°C, heating rate = 2°C/min melting point = 126°C.