AIR3-CT94-2218 Reactivity of Fatty Esters and Glycerol : New Methods

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AIR Cluster IV - Oils and Fats : Chemical Conversion : Paints/Coatings/Plastics : Vegetable Oil/Fat

	Proposal No:	AIR3-CT94-2218
	Date Prepared:	October 1996, April 1998, September 1999
	Source:	First Project Progress Report Second Project Progress Report Third Project Progress Report

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First Project Progress Report

INTRODUCTION

This project is looking at chemical and enzymic routes to new products derived from vegetable oils and glycerol. The activities are organised in a series of themes as described in the results below.

OBJECTIVE

The aim of this programme is to develop the methyl esters of vegetable oils, and glycerol, for new industrial applications, according to innovative and environmentally friendly means.

The choice of the participants was directed by the interest in the industrial applications, to the sights of the expertise of 2 industrial partners and of 2 specialized technical centres. Participants are accustomed moreover to working together or in sub-groups.

Tasks envisaged can be gathered in 3 topics of a general nature:

• New products, new uses, through the production of agromaterial by cross esterification on wooden sawdusts, through the use of derivatives of rough glycerin in polyurethanes.

• Obtaining new synthons through the analysis of epoxy rapeseed oil.

• Search for new derivatives for traditional applications listed under the generic term of surface-active chemicals, with a variable and controlled "HLB" balance.

The accent is put on the new conditions and functions of the derivatives. These issues are important because they are connected with the expansion of the development of non food uses of oils in Europe, in particular within the framework of the industrial set-aside reforms.

RESULTS

Theme 1: New compounds for new applications

Fatty esters of lignocellulose The first area investigated concerns the production of thermoplastic materials from fatty esters (or acids) combined with lignocellulosic wastes. Two separate approaches have been adopted (chemical and enzymatic) to test basic principles using pure cellulose and short chain saturated fatty acids (C4: O and C8: O). Treatments required to increase the reactivity of hydroxyl groups have been investigated together with the use of acetic anhydride, which has been shown to increase esterification yields providing a mixture of cellulose esters is obtained in the form of acetate and caprylate. The enzymatic route has been investigated using various hydrolases in several organic solvents. In the initial work, cellulose structural units (glucose, cellobiose) were selected as substrates to enable precise reaction conditions to be defined. In particular, it was shown that the esterification of glucose and cellobiose by butyric acid or caprylic acid methyl ester takes place in the presence of a hydrolase in pyridine. The application of these techniques was then extended to the more complex substrate such as cellulose. The most promising results were obtained with b cellulose.

Glycerol derivatives in polyurethane foams The objective of this work is the formulation of polyurethanes which can be swollen by water instead of the CFCs known to contribute to the hole in the ozone layer. So far, fourteen polyester resins have been prepared and their properties determined in terms of suitability for formulation. Two of them appeared promising and will be investigated during the formulation stage which is taking place during 1996.

Theme 2: New chemical intermediates

Catalytic epoxydation of fatty esters and acids These fatty epoxides are used as plasticisers and stabilisers (PVC), as components of resins or as oleochemical intermediates. Epoxydation of oleic methyl ester (OME) has been studied in various solvents in presence of several catalysts such as zeolites. Using these it was possible to obtain diols in a single step.

Chemical opening of epoxydised fatty acids and esters The opening of oleic methyl ester epoxide with various nucleophiles has been studied in detail since transformation could lead to several kinds of lubricants and plastisers. The epoxides used were derived from either rapeseed or sunflower methylesters. The nucleophiles tested included alcohols, carboxylic acids and amines. Various products have been made, but are still under evaluation.

Theme 3: New compounds for established applications

Preparation of fatty unsaturated alcohols Unsaturated fatty alcohols are known for their good lubricating properties under pressure and as detergents after slight modifications. A pilot development has been started using a heterogenous catalyst which gave a yield of oleyl alcohol of around 80 %. The catalytic system is being improved to increase this.

Reductive amination of fatty acids and esters Fatty amines are one of the major classes of derivatives used in oleochemistry. They have many applications reflecting their particular surfactant properties. It is especially true for the dialkylmethylamines. It has been found that fatty amine methylation is both faster and more selective when a methylating agent is used instead of methanol. Formation of final products depends on temperature.

Esteramides and polyesteramides The synthesis of these products, used as temporary coatings for the protection of iron sheets, has been evaluated and formulations which give effective protection of iron sheets stored in the open. Addition of acid was found to increase protection in many cases, while the effectiveness of amines depended on their structure.

Estolides Estolides are polyesters of fatty hydroxyacids which are prepared by autocondensation of the carboxylic function on the double bond of unsaturated fatty acids. So far authentic samples of estolides have been prepared from ricinoleic acid using perchloric acid as catalyst.

Selective esterification of glycerol Methods of obtaining pure monoglycerides, in one step avoiding any purification, has been investigated using a number of lipases for the selective synthesis of monoglycerides from oleic, palmitic and ricinoleic acid. Under the best conditions, yields with oleic acid are around 80%. This compares with chemical methods which gave a 70% yield with palmitic acid. Two reactions were studied in the presence of heterogeneous catalysts in emulsions. Using resins as catalyst the yield of glycerol 1 mono-oleate was over 95%. Zeolites were also investigated using oleic acid or rapeseed oil as raw material.

Aluminium silicate gave 75 % of conversion with 60 % glycerol mono oleate. Magnesium oxide based catalysts gave complete conversion with a high selectivity.

CONCLUSIONS

The fatty derivatives required have been prepared at the laboratory scale and the reactions investigated have worked well. Promising catalysts have been prepared and one of them (for use with unsaturated fatty alcohols) has been prepared in quantity for pilot scale development. Catalysts for epoxidation have been prepared and will be investigated further. Epoxide opening with several nucleophiles has been demonstrated, this will be scaled up to produce material for future application testing. Derivatives have been prepared for polyurethane foams and temporary coatings. These have yet to be evaluated. Laboratory scale production of fatty amines (ESIP) enables assessment with stability testing of the catalyst and design of a continuous device part of the continuing activity. Monoglycerides preparations are promising at the laboratory scale and samples are available for the first evaluations.

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Second Project Progress Report

Introduction
The aim of this project is to develop methyl esters of vegetable oils, and glycerol, for new industrial applications, according to innovative and environmentally friendly means. The accent is put on investigations of new conditions for production of such derivatives and finding new uses or functions of the derivatives. The project is important in the context of the expansion of non food uses of oils in Europe, in particular within the framework of the industrial set-aside reforms.

Objectives
The tasks can be grouped within three general themes as follows:

• New products and new uses for vegetable oils and their derivatives, through the production of agromaterials by cross esterification of lignocellulosic wastes or through the use of rough glycerine derivatives in polyurethanes.
• Obtaining new synthetic materials through preparation and transformation of epoxy fatty acids and esters.
• Identification of new derivatives for traditional applications including surfactants (with a variable and controlled "HLB" balance), fatty alcohols, amines, esteramides, estolides and monoglycerides.

Achievements
These are described on a theme by theme basis.

New compounds for new applications.
The first area of activity concerns the production of thermoplastic materials from fatty esters (or acids) and lignocellulosic wastes. The modification of lignocellulosic wastes with fatty acids has been investigated in order to obtain new thermoplastic materials. Waste esterification has involved both chemical and enzyme routes, using pure cellulose and short chain fatty acids as model compounds.

For the chemical pathway, the activities have concerned esterification reactions as follows:

• Improvement of the cellulose pre-treatment.
• Study of the acid catalyst effect.
• Kinetics of the reaction. Parameters analysis: experimental design.
• Characterisation of simple cellulose esters.
• Characterisation of mixed cellulose esters.
• Transesterification reactions:
• Searching for catalysts and reaction scaleup.

For the esterification reactions it was found that:

• In mixed cellulose esters, acetate groups confers rigidity and fatty substituents give hydrophobicity. The mixed properties open new opportunities for this kind of materials.
• Strong conditions for esterification lead to a high level of substitution but cellulose depolymerization is considerable. On the other hand, mild conditions lead to low esterification and cellulose is practically non- degraded. Nevertheless, even with a low level of esterification, high hydrophobicity is reached.

For the transesterification reactions it was found that potassium carbonate was the only catalyst to succeed in transesterification. However, the yields remain extremely low.

For the enzymatic pathways, the enzymes studied are hydrolases used several organic solvents. Studies focused on the possibilities of esterification of cellulose or its individual structural elements such as glucose and cellobiose, as well as fructose with lauric acid. Lipase was used in a water-restricted environment, in order to shift the reaction in the direction of synthesis. Various factors affecting the reaction rate were extensively studied. These included the role of water activity, the molar ratio of glucose/cellulose, the molar ratio of fatty acid/glucose, as well as the enzyme concentration Lipase can retain its catalytic ability in this non classic microenvironment. Therefore, it was hoped to demonstrate the esterification of cellulose, previously hydrolysed by HCl and neutralised. However, under the conditions the used results were negative.

Glycerol derivatives for the formulation of Polyurethanes
Fourteen polyols had been prepared during the first year of activity. They were then evaluated as components of polyurethanes. The results were very encouraging leading to pilot development. Since patenting has been considered no further details are given.

Catalytic epoxydation of fatty esters and acids
Fatty epoxides are used as plasticizers and stabilizers (PVC), as components of resins and are oleochemical intermediates. Epoxydation of Oleic Methyl Ester (OME) was investigated using various solvents in presence of several catalysts with hydrogen peroxide generally used as an oxidant. A new method for producing Ti zeolite catalysts has been developed. Acetonitrile is a suitable solvent for carrying out the epoxidation with hydrogen peroxide and Ti catalysts, allowing very high selectivities (95-100 %) of the desired product. At 50 degrees C the new Ti catalysts give 100 % selectivity to the epoxide. At the same time , the hydrophobic Ti material also had a higher activity and selectivity than hydrophilic catalysts when organic hydroperoxides, such as TBHP, were used as oxidants.

Chemical opening of epoxidized fatty acids and esters
The opening of oleic methyl ester epoxide with various nucleophiles was investigated since such transformation could lead to several kinds of lubricants and plastcizers. The epoxides used were based on rapeseed and sunflower methylesters. The nucleophiles tested included alcohols, carboxylic acids and amines. Further work included the use of octanol and butylamine. Samples of these materials have been prepared for testing.

Preparation of fatty unsaturated alcohols
Unsaturated fatty alcohols are known for their lubricating properties in high pressure systems pressures. They may also be used as detergents after slight modification. During this period useful data was obtained and used to optimise the pilot development. The main conclusions of the work were as follows. Using ruthenium catalysts, the selective hydrogenation of methyl oleate into oleyl alcohol gives total conversion of methyl oleate, a fraction containing mainly the unsaturated alcohol is obtained. Using cobalt catalysts the hydrogenation rate and the selectivity were not as good.

Reductive amination of fatty acids and esters
Fatty amines are the fourth largest type of derivative used in oleochemistry. They are used in a very wide range of applications that reflect their particular surfactant properties. This is especially true for the dialkylmethylamines. Earlier work had shown that methylation of fatty amines is both faster and more selective when a methylating agent is used rather than methanol. The process of N-Methylation with HMTA was investigated further using nickel catalysts. It was shown that, in presence of a nickel catalyst, the methyldodecylamine can be prepared selectively from the hydrogenation and N-methylation of dodecylnitrile with hexamethylenetetramine in mild experimental conditions.

Esteramides and polyesteramides
Samples of these compounds that are used as temporary coatings for protection of iron sheets protection were produced and their long term performance studied over period of one to six months. Only formulations containing a standoil and phosphoric or polyphosphoric acid, displayed effective protection against rust.

Estolides
Estolides are polyesters of fatty hydroxyacids. Samples have been prepared using various methods including the following:

• Self condensation of sunflower fatty acids in presence of ion exchange resins.
• Self condensation of epoxydized sunflower methyl ester in presence of oleic acid.

Selective esterification glycerol:monoglycerides
Monoglycerides have hundreds of applications as surfactants (food, pharmacy, cosmetics, ...). The aim is to obtain, in one step, pure monoglycerides, avoiding any purification. The added value for such compounds is rather good. Two routes (enzymatic and chemical). An enzymatic process leading mainly to monoricinoleoyl glycerol has been performed and monoester synthesis has been optimised using Novozym as catalyst. The main chemical pathway for monoglycerides production studied has been direct esterification of glycerol by oleic acid in the presence of emulsifiers. The results obtained were found to depend on the reaction conditions. Under optimum conditions the dispersed medium gave rise to a two phase system in which the oil phase contained 25 % by weight of the glycerol 1-monooleate. The transparent emulsion produced a crude single oil phase containing 22 % by weight of glycerol 1-monooleate. In the presence of a cation exchange resin, a 32 % by weight concentration of glycerol 1-monooleate was obtained. Transesterification of rapeseed oil with glycerol using basic catalysts derived from hydrotalcite was also investigated. The results showed that both catalysts provide adequate basicity for this reaction with a conversion yield of almost 100 % and around 80 % of selectivity for monoesters. Further work was carried out on the conversion, selectivity, and on the regeneration of the catalyst. Another approach was to investigate the preparation of monoglycerides by condensation of glycerol and fatty acids (e.g. oleic acid), in presence of ion-exchange resins. Previously the best results had been obtained with amberlyst resins. Further work examined the correlation between the level of resin cross-linking and selectivity of the reaction. The results demonstrated that a gel resin with a low cross-linking level is selective for the alpha- monoesterification of glycerol.

Conclusions
Generally the objectives have been achieved. The desired fatty derivatives have been prepared at the laboratory scale and a number of processes have been perfected. The catalysts prepared in the previous reporting period have been improved. Good results have been obtained for synthesis of polyurethanes, patenting has been considered. The opening of epoxides with octanol or butylamine can be scaled-up, enabling samples to be produced for application testings. Derivatives prepared for temporary coatings are effective. However, formulation costs have to be reduced. The first samples of fatty amines have been assessed and the stability of the catalyst studied in order to perfect the pilot device. Monoglycerides preparations have been improved and scaled-up. The supply of raw materials as well as the analytical measurements used have been standardised for all partners.