WO2018173011A1

WO2018173011A1 - Heterogeneous catalysts, preparation process and application thereof in fatty acid alkyl esters production process

Info

Publication number: WO2018173011A1
Application number: PCT/IB2018/052027
Authority: WO
Inventors: Andreia Filipa RIBEIRO DE OLIVEIRA PEIXOTO; Ana Cristina MOREIRA FREIRE; Sónia Isabel MATOS SILVA; Paula Cristina TEIXEIRA DA COSTA; Carlos Alberto DUARTE SOUSA; Bruno Miguel MAGALHÃES JARRAIS
Original assignee: Universidade Do Porto
Priority date: 2017-03-24
Filing date: 2018-03-26
Publication date: 2018-09-27
Also published as: PT109991A

Abstract

The present patent application describes heterogeneous catalysts, also referred to as solid acid catalysts, consisting of mixtures of aluminium/silicon (A1/Si) oxides and/or aluminosilicates having different A1/Si ratios including those of the (Na, Ca) _0.33 (A1, Mg) ₂ (Si₄O₁₀) (OH) ₂.nE₂0, A1₂Si₂O₅ (OH) ₄.nΗ₂Ο, Na_0.33 (A1, Mg) ₂ (Si₄O₁₀) (OH) ₂.nΗ₂Ο type, but not limited thereto, and sulfonic acid groups, as well as their preparation methods. The present technology further includes the application of the said heterogeneous catalysts in the processes for the production of fatty acid alkyl esters FAAE by esterification of free fatty acids (FFA) and transesterification of triacylglycerols (TG).

Description

DESCRIPTION

"HETEROGENEOUS CATALYSTS, PREPARATION PROCESS AND APPLICATION THEREOF IN FATTY ACID ALKYL ESTERS PRODUCTION

PROCESS"

Technical Field

The present application refers to the technical field of heterogeneous (acid) catalysts, the production thereof and the application thereof in fatty acid alkyl esters production .

Background of the art

Biodiesel is a clean, biodegradable renewable fuel and was recently considered one of the best candidates for replacing fossil fuels. However, the greatest obstacle against its commercialization, compared with oil-derived fuels, relates to high production costs. In fact, over recent years there has been a clear trend in using this type of biofuel due to the high price of crude oil and the predictable finite availability, making biodiesel a feasible alternative for diesel-derivatives production, especially for countries dependent on foreign oil supplies. Furthermore, the world production of biofuels is forecast to increase at an average of 4% per year up to 2030, despite the impact of economic recession in some countries investing on the development of biofuels. In particular, the European Union directive of 2009 for renewable energies established as a target the integration of 20% of renewable energies by 2020, based on concepts of reducing levels of greenhouse gas (GHG) emission and the dependency of energy imports to Europe. This is a strong boost for the use of biodiesel as part of the solution to the economic and energy problems. [1,2]

Among the factors contributing to the production costs of biodiesel, the raw material is considered to be the most important. Besides accounting for about 75-90% of the total operating cost, [3] its origin is directly related to its sustainability . In fact, although biodiesel is generally considered a viable "green" fuel that reduces harmful gas emissions, [1,3] the demand for these biofuels may have a very strong impact on the global agricultural market and on the price of food. The first-generation biodiesel (conventional) is typically produced from oilseed crops (plants containing high oil content, such as soybean, palm, colza/canola, etc.) . The increasing use of these crops for producing biofuels heightens concern for its sustainability, since the demand for these raw materials for certain markets (food and biofuels) began generating competition, economic and social problems with the significant hike in prices. The ongoing controversy of food vs. energy has been one of the greatest obstacles against the entry of biodiesel onto alternative fuels market. This led to the cultivation of non-edible plants (e.g.: jatropha) that can grow on marginal land that is unsuited and does not compete with the land used for agricultural crops, enabling the ILUC reduction. The use of oil and fat residues (waste cooking oil (WCO) , animal fat remains, residues from vegetable oil processing, etc.) started to gain some impact as alternative and sustainable raw materials for producing advanced biodiesel (second and third generation) . [4-12] The use of residues and non- edible oils for biodiesel production could minimize foods vs. energy competition and contribute to comply with the ecological and ethical requirements for biofuels production .

It is estimated that about 29 million tons of waste oil is generated every year. Eliminating waste oil and animal fat residues is a very significant problem in many parts of the world. This environmental problem could be minimized by suitable use and management of these residues as fuels. [9]

The use of WCO as raw material for producing biodiesel will not only enable a reduction in production costs, but will contribute to reduce an enormous environmental problem. Moreover, it has been proved that the performance of fuel engine is essentially the same as that noted when using biodiesel prepared from virgin oils, so there is no need to alter the engines. [13]

Today, algae are considered one of the most promising alternatives sources of non-edible oils for producing biodiesel. Although the large scale commercialization of biodiesel from algae oil has not yet had a great impact, major scientific efforts are being made to validate algae as an alternative raw material, since it is fast-growing and very oil-rich; the oil content in microalgae may exceed 80% by weight of the dry biomass.

There is also a strong impulse towards the re-use of animal fats, processed oils, such as palm oil, in order to increase the production of biodiesel and satisfy the needs for biodiesel in some countries, such as the USA, Europe, China, Malaysia and Canada. [4-8,10]

On the international market, transformed animal fats are classified as animal feed and as an industrial product, which makes its price low. Therefore, these low-quality grade raw materials drastically reduce the cost of biodiesel production allowing it to be more competitive with diesel-derivatives . However, the presence of a high content of free fatty acids (FFA) in these low quality materials has been a challenge for conventional biodiesel producers operating in homogeneous phase, especially when using the typical alkaline transesterification biodiesel production process.

Transesterification is the process whereby the triacylglycerols present in the fats or oils react with an alcohol in the presence of a catalyst to form esters and glycerol. The conventional processes used for the commercial production of biodiesel are catalysed by bases in homogeneous phase, which though resulting in high conversion percentages of triacylglycerols into FAAE (biodiesel) in a short reaction time, has several drawbacks. Firstly, it requires various steps: esters purification, glycerol separation ( another products from transesterification reaction) , complicated separation processes for removing the catalyst, limitations of the raw materials quality, with FFA contents not exceeding 2%, to prevent saponification side reactions occurring simultaneously with consequent decrease in catalytic activity of the catalyst. The presence of water is also a problem, since will promote the formation of FFA and, consequently, the deactivation of the catalyst. This is why raw-material oils in this type of process is refined vegetable oils to contribute to the proper operation and efficacy of these processes. There are other processes for the transesterification of triacylglycerols , such as the acid catalysis or even non- catalytic processes, such as the use of supercritical conditions. The transesterification process can be catalysed by strong Br0nsted acids in homogeneous phase (liquid), for example sulfonic acids or sulfuric acid, with high yields in the production of alkyl esters. However, the reactions are slow and require high reaction temperatures to achieve complete conversions. Moreover, the use of liquid acids as catalysts has a big disadvantage in this type of transesterification reactions when compared to alkalines, namely that water produced in the esterification of the FFA inhibits the transesterification of triacylglycerols. Another big disadvantage is the fact that these liquid acids possess highly corrosive character which causes problems of process machinery deterioration significantly increasing the maintenance costs. On the other hand, the process of acid catalysis is used to minimize the high content FFA raw materials contaminations However, in this case, there is a need to implement special units for acid neutralization, waste water treatment and methanol recover. One of the greatest challenges that these processes using homogeneous catalysts faces includes the separation and purification of the end product, the biodiesel, and the non-reutilization of the catalysts. The solid acid catalysts, such as those described in this patent application, are an alternative to the homogeneous catalysts as a form to overcome the problems associated to its use, for example, production of a high amount of residual waters and problems of corrosion of the infrastructures. These processes are described in literature [1,2,14-18] and in patent documents [19, 20, 21] . Another technique for the transesterification of vegetable oils, which does not use catalysts, is based on the use of alcohols in supercritical conditions. The alcoholysis reaction in the absence of a catalyst under high pressure and temperature conditions enables an increase in the solubility of the phases and decreases the mass transfer limitations. The reaction rate significantly increases in supercritical state and the reaction becomes complete in short time periods and requires very simple separation and purification steps. The supercritical method is more tolerant to the presence of water and FFA than the conventional process of alkaline catalytic transesterification . However, and despite the advantages, energy consumption and safety issues associated to these processes are the biggest obstacles and the high capital and operating costs mean that it is not suitable for large scale production. [6,9] patent documents: [22, 23, 24]

The development of heterogeneous catalysts such as solid acid and bases and enzymes may overcome most of the problems associated to the use of processes using homogeneous catalysts and it is in this sense that there is a growing interest to replace the homogeneous conventional catalysts for heterogeneous catalysts (solids) . The catalysts prepared and described in this patent application solve the operating problems associated to the use of homogeneous catalysts.

The process of transesterification of raw materials containing TG and the esterification of FFA to the respective alkyl esters using short-chain alcohols in the presence of lipases (enzymes) was patented by Nakayama et al . This method is particularly advantageous because it uses low cost (low quality) raw materials, such as animal fats, rendered fats, restaurant greases. However, lipases are expensive and highly sensitive to minor changes in temperature and pH, thereby limiting the industrial application of this method. [25]

Tested among other options, solid acid catalysts appear as a more effective and efficient alternative. [26] These may be feasible alternatives to the heterogeneous alkaline catalysts and to the conventional non-recyclable catalysts

(homogeneous) . The solid acid catalysts (of the Lewis type, such as mixtures of oxides, and of the Br0nsted type, such as materials containing acid groups or intrinsic acidity) combine the advantages of the heterogeneous catalysts with those of the mineral acids (liquid) enabling simultaneous esterification and transesteri fication of the raw materials. Another particular advantage of this class of catalysts is their efficiency in transforming raw materials rich in high-FFA contents into biodiesel, assuring the use of low-cost and easily-obtainable raw materials without the need of pre-treatment steps. Moreover, and since no mineral acids are used, the steps of neutralization and catalyst elimination are avoided. Additionally, the solid catalysts are easily handled and regenerated, are selective and reused, and the problems of corrosion are minimized or even surpassed and are applicable in continuous flow processes.

([27] and references thereof)

Patent document US7122688 B2 [28] describes a method to prepare alkyl esters from palmitic acid (PA) and soybean oil enriched with PA. The catalyst is mesoporous silica functionalized with sulfonic acids (alkyl and aryl) . The functionalized mesoporous silica presents a low number of acid centres (0.60 -1.44 mmol H⁺/g_materiai ) when compared to the catalysts prepared and described in the present patent application, which limits their acid catalytic efficiency and their reuse. Conversions to the palmitic acid in the respective methyl palmitate are high (% AP< 3), though no raw materials with high FFA content (%) were tested.

Patent document US20120130101 Al [29] describes the preparation and use of ceramic catalysts for preparing free fatty acid alkyl esters. The solid catalyst was obtained by mixing and sintering 0-80 wt . % active catalyst (metal oxides, carbonates or hydroxides) with a support material which is a mixture of silica and aluminium oxides. The materials prepared were used in the transesterification and esterification of vegetable and animal oils using high temperatures between 150-250°C and 120-250°C, respectively. The conversions obtained were superior to 90%, however the pressure and temperature conditions used are much higher than those used with the catalysts prepared and described in the present patent application.

Patent document MX2011012089 [30], describes an industrial process to obtain a mixture of FAME by esterification and transesterification of triacylglycerol using bentonite-type clay as catalyst. This clay was treated with water and with trifluoromethanesulfonic acid, the clay acts as support for the strong homogeneous acid catalyst. The acidity value of the materials prepared is not described, nor the results obtained in the transesterification and esterification processes of vegetable oils and animal fat. The process involves various pre-treatment steps of the raw materials, making it economically unfeasible for industrial application; there is no need of raw material pre-treatment with catalysts prepared and described in the present patent application .

Patent document WO2009016646 Al[31], describes a glycerol- based heterogeneous solid acid catalyst employed for the esterification of fatty acids. The catalyst is prepared with large quantities of concentrated sulfuric acid and at high temperatures of 200 and 300°C, which makes the process of producing the catalyst costly in energy terms. The catalysts display high acidity indices of 1.6-4.6 mmol H⁺/g_materiai_A but lower than some of the examples described in the present patent application displaying superacid characteristics (up to 6.0 mmol H⁺/g_materiai) ·

Patent document US8314045 Bl [32] describes the preparation of an acid catalyst with a porous silica support and a sulfonated carbon layer disposed within the pores of the silica support. Moreover, it discloses esterification methods of free fatty acids using different types of solid catalysts such as ion exchange resins [33], strongly acidic cationic exchange resins followed by strongly basic anionic exchange resins [34] . The main problem of ion exchange resins relates to their sensitivity to impurities such as metal ions, with a strong likelihood of becoming deactivated and, for this reason, there is a need of raw material pre-treatment , which is not is not necessary with the catalysts prepared and described in the present patent application whose raw materials are used directly without any prior treatment and no deactivation of catalyst is noted at all.

Patent document [35] US9328054 Bl of 2016 refers to a process that uses alcohol in a counterflow vapour-phase, a heterogeneous catalyst and in some embodiments, pressures lower than supercritical pressures for producing fatty acid esters. The reactors are superheated to temperatures between 200-260°C, meaning the processes are unfavourable in energy terms. The catalysts of the present patent application do not require high temperatures (< 120°C) , nor pressures near supercritical pressures to obtain conversions into FAAEs near or equal to 100%, which demonstrates its catalytic efficiency.

The use of non-edible raw materials and residues is compulsory for compliance with the ecological and ethical requirements of biodiesel. However, most residues in abundance contain high amounts of FFA. It is therefore imperative to develop efficient processes for biodiesel production which include the use of heterogeneous acid catalysts to eliminate the costs associated to the use of conventional catalysts and thus reducing the overall operation costs (maintenance, purification, waste water treatment, etc.) .

Summary

The present application describes heterogeneous acid catalysts (solids) based on mixtures of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having different Al/Si ratios and respective preparation method.

In an embodiment, said heterogeneous catalysts comprise: a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having the base formula selected from (Na, Ca) 0.33 (Al,Mg) 2 (Si₄Oio) (ΟΗ)₂.ΏΗ₂0 or Al₂Si₂0₅ (OH) ₄. Ώ¾0 or Nao.33 (Al,Mg) ₂ (S1₄O₁₀) (ΟΗ)₂.ΏΗ₂0, wherein n represents the number of ¾0 molecules;

and ,

an organosilane selected from benzyltriethoxysilane, benzyltrichlorosilane, 4-biphenyliltriethoxysilane, 2- (4- chlorosulfonylphenyl ) ethyltrichlorosilane, 2- (4- chlorosulfonylphenyl ) ethyltrimethoxysilane, 3- mercaptopropyltriethoxysilane, 3- mercaptopropyltrimethoxysilane, 1- (naphthylmethyl ) trichlorosilane, 1- (naphthylmethyl ) triethoxysilane, 1- (naphthylmethyl ) trimethoxysilane, phenyltrichlorosilane, phenyltriethoxysilane, phenyltrimethoxysilane phenethyltrichlorosilane, phenethyltrimethoxysilane, 4- phenylbutyltrimethoxysilane and 4- phenylbutyltrichlorosilane ;

and,

- a sulfonic group (-SO3H) .

In another embodiment the heterogeneous catalysts comprise: a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having the base formula selected from (Na, Ca) 0.33 (Al,Mg) 2 (S14O10) (ΟΗ)₂.ΏΗ₂0 or Al₂Si₂0₅ (OH) ₄. ΏΗ₂0 or Nao.33 (Al,Mg) 2 (S14O10) (ΟΗ)₂.ΏΗ₂0, wherein n represents the number of H₂0 molecules;

and,

- a sulfonic group (-SO3H) .

In another embodiment the heterogeneous catalysts comprise: a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having the base formula selected from (Na, Ca) 0.33 (Al,Mg) 2 ( S 14O10 ) (ΟΗ)₂.ΏΗ₂0 or Al₂Si₂0₅ (OH) ₄. ΏΗ₂0 or Nao.33 (Al,Mg) 2 ( S 14O10 ) (OH)₂.-nH₂0, wherein n represents the number of H₂0 molecules; and,

- an organic precursor selected from fluoro-alkyl-sultones , alkyl-sultones , benzyl alcohol and organosulfonates ;

and ,

- a sulfonic group (-SO₃H) .

In an embodiment, the catalysts comprising a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having base formula (Na, Ca) 0.33 (Al,Mg) ₂ (Si₄Oi₀) (OH) ₂. nU₂ present a surface area between 200 and 300 m²/g and an acidity between 0.4 to 6.0 mmol H⁺/g_materiai ·

In an embodiment, the catalysts comprising a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having base formula AI₂S1₂O₅ (OH) ₄. ΉΗ₂0 present a surface area between 50 and 150 m²/g, and an acidity between 0.6 and 3.0 mmol H⁺g_materiai ·

In an embodiment, the catalysts comprising a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having base formula Nao.₃₃ (Al,Mg) ₂ (Si₄Oi₀) (ΟΗ)₂.ΉΗ₂0 present a surface area between 50 and 100 m²/g, and an acidity between 2.0 and 5.0 mmol H⁺/g_materiai ·

In an embodiment the preparation method for heterogeneous catalysts comprises:

a silylation reaction between a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicate selected from (Na, Ca) 0.33 (Al,Mg) ₂ (Si₄Oi₀) (OH) ₂. ΏΗ₂0 or Al₂Si₂0₅ (OH) ₄. nE₂0 or Nao.33 (Al,Mg) ₂ (S14O10) (OH) ₂. ΏΗ₂0, and an organosilane selected from benzyltriethoxysilane, benzyltrichlorosilane, 4-biphenyliltriethoxysilane, 2- (4- chlorosulfonylphenyl ) ethyltrichlorosilane, 2- (4- chlorosulfonylphenyl ) ethyltrimethoxysilane, 3- mercaptopropyltriethoxysilane, 3- mercaptopropyltrimethoxysilane, 1-

(naphthylmethyl ) trichlorosilane, 1-

(naphthylmethyl ) triethoxysilane, 1-

(naphthylmethyl ) trimethoxysilane, yltrichlorosilane, yltriethoxysilane, phenyltrimethoxysilane phenethyltrichlorosilane, phenethyltrimethoxysilane, 4- phenylbutyltrimethoxysilane and 4- phenylbutyltrichlorosilane ;

- oxidation of the intermediary compound obtained in the prior step with one or more oxidants selected from hydrogen peroxide (H₂O₂) , nitric acid (HNO₃) , potassium permanganate

(ΚΜηθ₄) , potassium chromate (K^CrO,}) and sodium hypochlorite

(NaCIO) .

In an embodiment the method of preparing heterogeneous catalysts as described in the prior embodiment additionally comprises an acid activation step with a mineral acid selected from sulfuric (H₂S0₄) , phosphoric (H₃PO₄) , hydrofluoric (HF) , nitric (HNO₃) , hydrochloric (HC1), chlorosulfonic (HSO₃CI) and acetic (CH₃CO₂H) acids.

In an embodiment the preparation method for heterogeneous catalysts comprises:

a silylation reaction between a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicate selected from (Na, Ca) 0.33 (Al,Mg) ₂ (Si₄Oi₀) (OH) ₂. nE₂0 or Al₂Si₂0₅ (OH) 4. nE₂0 or Nao.33 (Al,Mg) 2 (S14O10) (OH) 2 · Ή¾0, and an organosilane selected from benzyltriethoxysilane, benzyltrichlorosilane, 4-biphenyliltriethoxysilane, 2- (4- chlorosulfonylphenyl ) ethyltrichlorosilane, 2- (4- chlorosulfonylphenyl ) ethyltrimethoxysilane, 3- mercaptopropyltriethoxysilane, 3- mercaptopropyltrimethoxysilane, 1-

(naphthylmethyl ) trichlorosilane, 1-

(naphthylmethyl ) triethoxysilane, 1-

- acid activation of the intermediary compound obtained in the prior step with a mineral acid selected from sulfuric (H₂SO₄) , phosphoric (H₃PO₄) , hydrofluoric (HF) , nitric (HNO₃) , hydrochloric (HC1), chlorosulfonic (HSO₃CI) and acetic (CH₃CO₂H) acids.

In an embodiment the preparation method for heterogeneous catalysts comprises:

- direct activation acid of a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicate selected from (Na, Ca) 0.33 (Al,Mg) 2 (S14O10) (ΟΗ)₂.ΏΗ₂0 or Al₂Si₂0₅ (OH) ₄. ΏΗ₂0 or Nao.₃₃ (Al,Mg) ₂ (S1₄O₁₀) (ΟΗ)₂.ΏΗ₂0, with a mineral acid selected from sulfuric (H₂SO₄) , phosphoric (H₃PO₄) , hydrofluoric (HF) , nitric (HNO₃) , hydrochloric (HC1), chlorosulfonic (HSO₃CI) and acetic (CH₃C0₂H) acids.

In another embodiment the preparation method for heterogeneous catalysts comprises:

- a reaction between a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicate selected from (Na, Ca) 0.33 (Al,Mg) 2 (S14O10) (ΟΗ)₂.ΏΗ₂0 or Al₂Si₂0₅ (OH) ₄. ΏΗ₂0 or Nao.33 (Al,Mg) 2 (S14O10) (OH)₂.-nH₂0, and an organic precursor selected from fluoro-alkyl-sultones , alkyl-sultones , benzyl alcohol and organosulfonates . In an embodiment the method of preparing heterogeneous catalysts as defined in the preceding embodiment additionally comprises an acid activation step with a mineral acid selected from sulfuric (H₂SO₄) , phosphoric (H₃PO₄) , hydrofluoric (HF) , nitric (HNO₃) , hydrochloric (HC1), chlorosulfonic (HS0₃C1) and acetic (CH₃C0₂H) acids.

In an embodiment a silylation reaction occurs in a non- hydrolytic solvent, carried out under inert atmosphere, at a temperature between 50 - 140°C, with stirring in a period between 2-24 hours.

In another embodiment a silylation reaction is carried out at a temperature of 120°C for 6 hours.

In an embodiment the catalysts are separated from the reaction medium by centrifugation and/or filtration.

In an embodiment the heterogeneous catalysts as defined in this patent application, are used in the production of fatty acid alkyl esters, by esterification and/or transesterification of free fatty acids and/or triacylglycerols and mixtures thereof and/or in catalytic reactions of hydrotreatment , condensation, alkylation, isomerization, dehydration, opening of epoxides, hydrolysis or aldol reactions.

General Description

The present application describes heterogeneous catalysts (solids) based on mixtures of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having different Al/Si ratios and respective preparation method. The catalysts described herein are designated by X-CAT(1-12), Y-CAT(1-12) and Z-CAT(1-12) . The present technology is not limited to heterogeneous acid catalysts and the preparation thereof, but also includes their application in the esterification of free fatty acids (FFA) and transesterification of triacylglycerols (TG) for producing fatty acid alkyl esters

(FAAE) and includes the process and technology for obtaining them, using traditional and alternative raw materials, vegetable oils and animal fats with FFA percentages from 0 to 100%.

The present patent application also describes a simple process of transforming different types of raw materials of vegetable origin, animal origin, and residues thereof, residues from forest and agricultural biomass (ligno- cellulosic) and the processing thereof, non-edible crops

(grasses, miscanthus, algae) , industrial residues, residues of non-edible oils, waste oil, among others, for producing FAAE that comply with the requirements: ecological - low emissions of CO₂ and high reduction of greenhouse gases

(GHG) ; ethical - attain zero or very low impact in indirect land use change (ILUC); and economic - reduction in raw material associated costs for biodiesel production; compulsory for producing advanced biofuels and bioproducts.

Additionally, the catalysts described herein and designated by X-CAT(1-12), Y-CAT(1-12) and Z-CAT(1-12), display excellent activity as heterogeneous catalysts acids for producing FAAE associated to a simplified industrial process. The application of the methodology of preparing the heterogeneous catalysts, which the present patent application constitutes, is not limited to the production of FAAE from esterification and transesterification reactions, but may still be used in catalytic reactions of hydrotreatment , condensation, alkylation, isomerization, dehydration, opening of epoxides, hydrolysis, aldol reactions, but is not limited thereto.

The present technology also constitute an alternative to conventional and outdated processes of producing FAAE using liquid inorganic acids and are associated to high expenses with maintenance and waste water treatment. These processes also have the additional disadvantage of not being efficient in transforming raw materials rich in FFA (up to 100% of FFA) and, consequently, oblige the need to adapt and/or alter the conventional processes for alternative processes which includes that described by the present patent application and which enable efficient and clean production of FAAE from any type of raw material.

The catalysts prepared and described in this patent application and used in the production of FAAE enable realization conditions such as: pressures of 1 to 20 atm, temperatures between 60 and 160°C, batch or continuous reactions; in the transesteri fication reaction and/or esterification of free fatty acids such as, but not limited to these, valeric, myristic, lauric, palmitic, palmitoleic, stearic, oleic, linoleic acids, or different percentages of mixtures of FFA or mixtures of FFA with TG (but not limited to these) which present conversions of 100% in some of the examples of embodiments. The heterogeneous catalysts prepared and described in this patent application enable the use of any type of raw material comprised of free fatty acids (0 to 100%) and/or triacylglycerols including the transformation of residues of any type and quality having high amounts of FFA (up to 100%), water and other impurities, in FAAE, having reaction times of 30 to 240 min, in one step or in 2 or 3 steps, with raw material : alcohol ratio of 1:1 to 1:60, and catalyst mass percentages of 2 to 10%. The use of heterogeneous catalysts prepared and described in this patent application enables all type of raw materials, including residues of animal or vegetable origin with no need of pre-treatment with the advantage of catalyst reusability from 2 to 20 times without loss of activity.

Detailed Description of the drawings

FIGURE 1: Representative layout of the catalysts prepared and described in this patent application, X-CAT(1-12), Y- CAT(1-12) and Z-CAT ( 1-12 ) ) . (a) Reaction with the silylation agent ORG1, followed by oxidation with: 1) H₂O₂ - (X-CAT1, Y-CAT1 and Z-CAT1); 2) HN0₃ - (X-CAT2, Y-CAT2 and Z-CAT2 ) ; 3) H₂0₂ - S0C1₂ (X-CAT3 , Y-CAT3 and Z-CAT3 ) ; or sulfonation with HSO₃CI . (b) Reaction with the silylation agent ORG2 or ORG3 (n=0), followed by reaction with H₂SO₄ to give X-CAT5, Y-CAT5 and Z-CAT5 and X-CAT7, Y-CAT7 and Z- CAT7, respectively; or followed by reaction with HSO₃CI to give X-CAT6, Y-CAT6 and Z-CAT6 and X-CAT8, Y-CAT8 and Z- CAT8, respectively, (c) Reaction with the silylation agent ORG4 (n=2) to give the catalysts X-CAT4, Y-CAT4 and Z-CAT4. (d) Direct acid activation with HSO₃CI or H₂SO₄. (e) Reaction with the precursor fluoro-alkyl-sultone, followed by optional acid activation with a mineral acid.

(d) Direct acid activation with HS0₃C1 or H₂S0₄. (e) Reaction with the precursor fluoro-alkyl-sultone, followed by optional acid activation with a mineral acid.

Description of the embodiments

Below is a detailed description of some embodiments, which are not, however, intended to limit the scope of the present application.

Heterogeneous catalysts

The catalysts of the present technology and described herein are based on a mixture of oxides of (Al/Si) and/or aluminosilicates of the type

(Na, Ca) ₀.₃₃ (Al,Mg) ₂ (Si₄Oio) (OH) ₂. -nH₂0 (designated herein X- AlSi), Al₂Si₂0₅ (OH) ₄. ΏΗ₂0 (designated herein Y-AISi), Nao.33 (Al,Mg) 2 (S14O10) (OH) 2. -n¾0 (designated herein Z-AISi), but not limited thereto, wherein n represents the number of molecules of water.

Throughout this patent application, the catalysts produced from oxides Al/Si and/or aluminosilicates X-AISi, Y-AISi and Z-AISi, will be designated by X-CAT(1-12), Y-CAT(1-12) and Z-CAT(1-12), respectively, wherein (1-12) they merely serve to identify the different catalysts (described herein for illustration) within each class (X, Y or Z) based on their method of production.

In some embodiments shown herein the catalysts prepared present superacid characteristics (0.4 to 6.0 mmol H⁺/g_materiai) and surface areas between 50 and 300 m²/g.

In an embodiment the catalysts X-CAT have surface areas between 200-300 m²/g and an acidity from 0.4 to 6.0 mmol HV g t starting material ) , wherein X-CAT 1 and X-CAT 12 have an acidity of 0 . 4 , X - CAT 4 and X-CAT 9 of 0 . 7 , X-CAT 6 and X- CAT 1 0 of 6 . 0 and X-CAT 1 1 of 3 . 0 mmol H⁺/ g_materiai .

In another embodiment, the catalysts Y-CAT has a surface area of 50-150 m²/g, acidity from 0.6 to 3.0 mmol

H⁺/g_materi_ai , wherein Y-CAT1 has an acidity of 0.6, Y-CAT 6 of 3.0 and Y-CAT10 of 2.0 mmol H⁺/g_material.

In another embodiment the catalysts Z-CAT have a surface area of 50-100 m²/g, an acidity from 2.0 to 5.0 mmol H⁺/g_materiai _A wherein Z-CAT10 has an acidity of 2.0 and Z- CAT11 of 5.0 mmol H⁺/g_materiai .

Heterogeneous catalysts production methodology

In some embodiments, the heterogeneous catalysts are prepared by silylation reaction with silylation agents of the organosilane type with different hydrolysable groups: ethoxy-, methoxy- and chloro-, and different functional groups phenyl-, benzyl-, naphthyl- biphenyl-, mercapto-, chlorosulfonyl-, selected from, but not limited to, benzyltriethoxysilane, benzyltrichlorosilane, 4 - biphenyliltriethoxysilane, 2- ( 4 - chlorosulfonylphenyl ) ethyltrichlorosilane, 2- ( 4 - chlorosulfonylphenyl ) ethyltrimethoxysilane, 3- mercaptopropyltriethoxysilane, 3- mercaptopropyltrimethoxysilane, 1- (naphthylmethyl ) trichlorosilane, 1- (naphthylmethyl ) triethoxysilane, 1- (naphthylmethyl ) trimethoxysilane, phenyltrichlorosilane, phenyltriethoxysilane, phenyltrimethoxysilane phenethyltrichlorosilane, phenethyltrimethoxysilane, 4 - phenylbutyltrimethoxysilane and 4- phenylbutyltrichlorosilane .

For illustration, the organosilane mercaptopropyltrimethoxysilane is designated ORG-1, the phenyltrimethoxysilane designated ORG-2, the phenyltriethoxysilane is designated ORG-3 and the 2- (4- chlorosulfonylphenyl ) ethyltrimethoxysilane is designated ORG-4, in this patent application.

Hereinafter, for illustration, the intermediate products that underwent the silylation process but which do not yet have catalyst activity, have the suffix ORG1, ORG2, ORG3 or ORG4, depending on the organosilane used to obtain it (e.g. X-AlSi-ORGl, Y-AlSi-ORG3, etc.) .

After hydrolysis, the silanol reactive group formed condenses with the reactive groups present in the mixture of Al/Si oxides and/or aluminosilicates of the type

(Na,Ca) ₀ . 33(Al,Mg)₂(Si₄Oio) (ΟΗ)₂. ΏΗ₂0, Al₂Si₂0₅ (OH) ₄. Ώ¾0,

Na₀ . 33 (Al,Mg) ₂ (Si₄Oio) (ΟΗ)₂. ΏΗ₂0 enabling the introduction of

(bi ) functional groups with acid properties and/or with reactive (organic) groups suitable for subsequent transformation into strong acid groups.

In some embodiments a silylation reaction is carried out under inert atmosphere (e.g. nitrogen), using temperatures between 50 and 140°C, regular stirring periods varying between 2-24 hours.

In another embodiment a silylation reaction is carried out at a temperature of 120°C for 6 hours. In some embodiments, the catalyst is prepared by silylation with the silylation agents ORG1, ORG2, ORG3 and ORG4 with different hydrolysable groups, alkoxy, acyloxy or halogens, followed by acid activation, with the following mineral acids, but not limited to, sulfuric (H₂SO₄) , phosphoric ( H₃PO4 ) , hydrofluoric (HF) , nitric (HNO₃) , hydrochloric (HC1), chlorosulfonic (HS0₃C1) and acetic (CH₃C0₂H) .

In some embodiments, the catalyst is prepared by the silylation reaction with mercapto- type silylation agents with different hydrolysable groups: alkoxy, acyloxy or halogens, including 3-mercaptopropyltrimethoxysilane, followed by an oxidation process. The oxidation process may be made using the following oxidants or combination thereof, but not limited to, hydrogen peroxide (H₂O₂) , nitric acid (HNO3) , potassium permanganate (ΚΜηθ₄) , potassium chromate (K^CrC^) and sodium hypochlorite (NaCIO) .

In some embodiments, the catalyst is prepared by silylation reaction with phenyl-, benzyl-, naphthyl- biphenyl-, mercapto- type silylation agents with different hydrolysable groups: alkoxy, acyloxy or halogens, including the silylation agents ORG1, ORG2 and ORG3, followed by acid treatment. The acid treatment is performed with mineral acids of the, but not limited to, H₂S0₄, H3PO4 , HF, HN0₃, HC1, HS O₃C I , CH₃CO₂H and p-toluenosulfonic acid (C₇H₇SO₃H) type .

In some embodiments, the starting material, a mixture of Al/Si oxides and/or aluminosilicates of the type X-AISi, Y- AlSi and Z-AISi, already displays Lewis and/or Br0nsted acid properties. In some embodiments, the catalyst is prepared by direct or indirect activation of the starting material, a mixture of Al/Si oxides and/or aluminosilicates of the type X-AlSi, Y- AlSi and Z-AlSi:

1) Direct activation is carried out by mineral acids or sulfonic organic acids such as H2 S O4 , H₃PO4 , HF, HNO₃, HC1, HSO₃CI, CH₃CO₂H and C₇H₇SO₃H, but this activation is not limited to these examples.

2) Indirect activation is performed by reaction of the base materials with Al/Si mixed oxides and/or aluminosilicates of the type X-AlSi, Y-AISi and Z-AISi with different precursors: fluoro-alkyl-sultones , alkyl-sultones , benzyl alcohol, organosulfonates and other derivatives, but not limited thereto. Indirect activation may be followed by acid activation by mineral acids or sulfonic organic acids such as H2 S O4 , H3PO4 , HF, HN0₃, HC1, HSO3CI, CH₃C0₂H and C7H7 S O₃H , but this activation is not limited to these examples .

The catalysts of the present technology and described herein are easily separated from the reaction medium by centrifugation and/or filtration (in the case of the batch reactor), is easily recoverable and reusable.

FAAEs Production

The processes described herein for FAAE production uses solid acid catalysts, the preparation procedure of which is also described in this patent application.

The heterogeneous catalysts and methods described herein constitute an efficient process for fatty acid alkyl esters production (biodiesel and bioproducts) with high yields under mild pressure and temperature conditions. The catalysts prepared and described herein were applied to a one-step process for methyl esters (FAME- fatty acid methyl ester) and ethyl esters fatty acids production from the esterification and/or transesterification reaction of free fatty acids such as, but not limited to valeric, myristic, lauric, palmitic, palmitoleic, stearic, oleic, linoleic acids, or different percentages of mixtures of FFA or mixtures of FFA with TG (but not limited thereto) .

In some embodiments, FFA, mixtures of FFA or mixtures of FFA with TG, react with the alcohol in the presence of a catalyst prepared according to the method described herein for producing fatty acid alkyl esters.

In an embodiment the alcohol used in this procedure is, but not limited to, methanol or ethanol.

In an embodiment the molar ratio of raw material (RM) : methanol/ethanol may vary from 1:0.5 to 1:60. In some embodiments, the conversion achieved 90 to 100%.

In another embodiment, the methyl/ethyl esters fatty acids produced by the process described herein include, but are not limited to, valeric, myristic, lauric, palmitic, palmitoleic, stearic, oleic, linoleic acids, or mixtures thereof and/or mixtures of other FFA and mixtures of FFA with TG.

In an embodiment the conditions used for producing alkyl esters are a temperature of 120°C and a pressure of 8 bar. In some embodiments, the catalysts of the present technology and described herein are efficient in the reaction (with atomic efficiency in agreement with the second principle of green chemistry) of transesteri fication and esterification of pure vegetable oils (TG and FFA) , or other raw materials comprised of mixtures of FFA and TG, using mild conditions of temperature between 60-160°C and pressure of 1 to 20 atm. The products obtained are fatty acid alkyl esters including but not limited to, methyl and ethyl esters fatty acid , and pure glycerol.

The catalysts described herein have an excellent catalytic efficiency in the esterification and transesterification of FFA, TG, mixtures of FFA and mixtures of FFA with TG. They display the advantages of the heterogeneous catalysts, and avoid the use of toxic and corrosive chemical products, contributing to simplify the conventional industrial processes with consequent increase of the industrial process economy. Furthermore, contrary to conventional catalysts, the heterogeneous catalysts of the present technology are very efficient for raw materials with high content of free fatty acids, water and other impurities. Therefore, there are no limitations in the quality and type of raw materials to be used with the catalysts of the present technology.

The examples consider raw materials of animal and vegetable origin, but not limited thereto, having 0 to 100% of FFA. These raw materials may be pure or result from the hydrolysis of vegetable oils and animal fats, vegetable or aquatic biomass, residues of waste oil and fats. Examples of residues of waste oil include residues of oils and fats, by-products of oil processing/refinery plants, food processing plants, restaurants, households in general; residues of oils and fats resulting from the processing of oils and fats, such as margarines and modified fats; residues of oils and fats such as vegetable oils and fats used as lubrication oils, residues of oils and fats from the processing of edible oils; edible oils and fats from returned merchandise, such as defective products and expired products, oils and animal fats occurring in edible fish or meat processing.

The process for producing FAAE from FFA, mixtures of FFA and mixtures of FFA with TG (and all the raw materials containing FFA and TG) and alcohol, and a solid catalyst prepared and described by the methods comprised in this patent application is a heterogeneous process and the catalyst may be separated from the reaction liquid by separation techniques such as, but not limited to, centrifugation/decanting and filtration.

There are no morphological limitations on the catalyst. It may be used as a pulverized sample or as granules or extrusion moulded, pelletized, beaded and/or atomized.

The process described herein for producing alkyl esters of FFA, mixtures of FFA and mixtures of FFA with TG, is a single-step process. The process described herein avoids pre-treatment steps of raw materials, the steps of saponification, neutralization, elimination of the catalyst, etc. associated to the conventional processes. The conventional liquid catalysts may require treatment with mineral acids and alkaline bases, increasing the separation costs of the catalyst and consequently the operating costs. The catalysts described herein lead to processes having excellent cost-benefit ratio and sustainability .

The catalysts were prepared using the methods described in examples of procedures which are set out below. Some examples of the catalytic results are presented in Tables 1, 2 and 3.

Table 1 X-CAT

Cat.= catalyst; P= Pressure; T= Temperature; FFA - Free fatty acids; TG - Triacylglycerols ; RM: raw material

a⁾ Mix. FFA: 100% FFA (mixture of acids: lauric, palmitic, stearic, oleic and linoleic) .

RM1 : 82^£ FFA and 18^£ TG

RM2 : 87^£ FFA and 13^£ TG

d) RM3 : 1% FFA and 99% TG.

e) RM4 : 25^£ FFA and 75^£ TG

RM5 : 34^£ FFA and 66^£ TG

9» determined by GC-FID, HPLC and 1HRMN Table 2 Y-CAT

Cat.= catalyst; P= Pressure; T= Temperature; FFA - Free fatty acids; TG - Triacylglycerols ; RM:raw material

a⁾ Mix. FFA: 100% FFA (mixture of acids: lauric, palmitic, stearic , oleic and linoleic

b⁾ RM1: 82 % FFA and 18^£ TG.

c⁾ RM2: 87 % FFA and 13^£ TG.

d⁾ RM3: 1% FFA and 99% TG.

25 % FFA and 75^£ TG.

f⁾ RM5 : 34 % FFA and 66^£ TG.

g⁾ determined by GC-FID, HPLC and 1HRMN

Table 3 Z -CAT

Cat.= catalyst; P= Pressure; T= Temperature; FFA - Free fatty acids; TG - Triacylglycerols; RM:raw material ^a) Mix. FFA: 100% FFA (mixture of acids: lauric, palmitic, stearic, oleic and linoleic) .

b) RM1 : 82^£ 5 FFA and 18^£ 5 TG

c) RM2 : 87^£ 5 FFA and 13^£ 5 TG

d) RM3 : 1% FFA and 99% TG.

e) RM4 : 25^£ 5 FFA and 75^£ 5 TG

f ) RM5 : 34^£ 5 FFA and 66^£ 5 TG

g⁾ determined by GC-FID, HPLC and 1HRMN

Embodiments

Examples

The present technology will be described by examples of procedures, but is not at all limited to these examples.

Catalysts preparation referred in the present patent application is based on different mixtures of Al/Si oxides and/or aluminosilicates of the type X-AlSi, Y-AlSi and Z- AlSi .

Example 1: The starting materials X-AlSi, Y-AlSi or Z-AlSi (2 g) were subjected to reflux, in anhydrous toluene or other non-hydrolytic solvent (100 mL) , with the silylation agent ORG1 (with the mercapto-propyl functional group, 6 mmol, n=2, figure 1) , under stirring and nitrogen atmosphere, for 24 hours. After this period, the solid was separated by centrifugation and/or filtration and washing with toluene or other non-hydrolytic solvent (100 mL) , under reflux, for 1 hour. After washing, the solids X-AlSi- ORG1, Y-AlSi-ORGl or Z-AlSi-ORGl were filtered and placed in an oven, between 100-120°C.

Example 1.1: The catalysts X-CAT1, Y-CAT1 or Z-CAT1 (see figure 1) were prepared using the functionalized materials X-AlSi-ORGl, Y-AlSi-ORGl or Z-AlSi-ORGl, by treatment with H₂O₂ 30% (v/v) (2.66 mol), for 24 hours, under stirring and at room temperature. After 12 hours of reaction, concentrated sulfuric acid (0.5 mL) was added and the reaction was maintained for a further 12 hours. Afterwards, the catalysts X-CAT1, Y-CAT1 or Z-CAT1 were isolated by filtration and/or centrifugation and dried overnight using an oven at 100-120°C. The catalysts X-CAT1 and Y-CAT1 display an acidity of 0.4 and 0.6 mmol H⁺/g_materiai, respectively .

Example 1.2: The catalysts X-CAT2, Y-CAT2 or Z-CAT2 (see figure 1) were prepared using the method described in example 1, with an additional procedure: the materials X- AlSi-ORGl, Y-AlSi-ORGl or Z-AlSi-ORGl were treated with an aqueous solution of nitric acid (0.56 mol) . The mixtures were stirred for 6 hours at room temperature. Subsequently, the catalysts X-CAT2, Y-CAT2 or Z-CAT2 were isolated by filtration and/or centrifugation and dried in an oven at 100-120°C.

Example 1.3: The catalysts X-CAT3, Y-CAT3 or Z-CAT3 (see figure 1) were prepared using the method described in example 1, followed by oxidative chlorination with H₂O₂- SOCI2, using S0C1₂ (8 mmol) and H₂0₂ 30% (v/v) (24 mmol), in 20 mL of CH₃CN at 25°C and stirring for 1 hour. The solids were removed by filtration and/or centrifugation, washed once with CH₃CN and dried overnight at 100-120°C. The hydrolysis of the chlorosulfonyl- (-SO₂CI) groups to the corresponding sulfonic acids (-SO3H) was carried out under acid conditions and the catalysts X-CAT3 , Y-CAT3 or Z-CAT3 were obtained. Example 1.4: The catalysts X-CAT4, Y-CAT4 or Z-CAT4 (see figure 1) were prepared using the method described in example 1, with an additional procedure: The functionalized materials X-AlSi-ORGl, Y-AlSi-ORGl or Z-AlSi-ORGl (2 g) were dispersed in CHCI₃ (25 mL) and transformed, subsequently, by dropwise addition of chlorosulfonic acid (9 mmol) . Afterwards, the mixture was stirred until total removal of the HC1 formed. The catalysts obtained, X-CAT4, Y-CAT4 or Z-CAT4 , were washed with methanol, isolated by filtration and/or centrifugation and dried at 100-120°C. The catalyst X-CAT4 displays an acidity of 0.7 mmol

H⁺/Cfmaterial .

Example 2: The starting materials X-AISi, Y-AISi or Z-AISi (2 g) were subjected to reflux in anhydrous toluene or other non-hydrolytic solvent (100 mL) , with the silylation agents ORG2 (with phenylmethoxy-functional group, 4.99 mmol) and ORG3 (with phenylethoxy-functional group, 6.05 mmol, n=0 and R=H, figure 1), under stirring and under nitrogen atmosphere for 24 hours. After this period, the solids were separated by centrifugation and/or filtration and washed with toluene (100 mL) , under reflux, for 1 hour. Finally, the functionalized materials X-AlSi-ORG2, Y-AlSi- ORG2 or Z-AlSi-ORG2 and X-AlSi-ORG3, Y-AlSi-ORG3 or Z-AlSi- ORG3 were placed in oven at 100-120°C.

Example 2.1: The functionalized materials X-AlSi-ORG2, Y- AlSi-ORG2 or Z-AlSi-ORG2 and X-AlSi-ORG3, Y-AlSi-ORG3 or Z- AlSi-ORG3, obtained in example 2, were used as base for preparing the catalysts X-CAT5 , Y-CAT5 or Z-CAT5 and X- CAT7, Y-CAT7 or Z-CAT7 (see figure 1), by suspension in anhydrous diethyl ether (50 mL) and subsequent addition of 6 mL of sulfuric acid (5 M) . The mixture was stirred for 1 hour at ambient temperature. After this period, the solid was separated by filtration and/or centrifugation and washed with water, up to pH ~ 7. Finally, the catalysts X- CAT5, Y-CAT5 or Z-CAT5 and X-CAT7, Y-CAT7 or Z-CAT7 were recovered by filtration and/or centrifugation and dried at 100-120°C.

Example 2.2: The catalysts X-CAT6, Y-CAT6 or Z-CAT 6 and X- CAT8, Y-CAT8 or Z-CAT8 were prepared from the functionalized materials X-AlSi-ORG2, Y-AlSi-ORG2 or Z- AlSi-ORG2 and X-AlSi-ORG3, Y-AlSi-ORG3 or Z-AlSi-ORG3 (described in example 2, see figure 1), by dispersion in dichloromethane or other non-hydrolytic solvent (40 mL) and subsequent addition of chlorosulfonic acid (3.7 x lCr² mol) . The reaction was maintained in reflux and stirred for 6 hours. After this period, the catalysts X-CAT 6 , Y-CAT6 or Z-CAT 6 and X-CAT8, Y-CAT8 or Z-CAT8 were separated and washed several times with dichloromethane. Finally, the catalysts were filtered and/or centrifuged and dried in an oven at 100-120°C. The catalyst X-CAT6 displays an acidity of 3.0 mmol H⁺/g_materiai .

Example 3: The catalysts X-CAT9, Y-CAT9 or Z-CAT9 were prepared directly by silylation of the starting materials X-AlSi, Y-AlSi or Z-AlSi (2 g) , by suspension in anhydrous toluene or other non-hydrolytic solvent (80 mL) , with the silylation agent ORG4 (with 4- (chlorosulfonylphenyl) ethyl- functional group, 1.2 mmol, n=2 and R=S03C1, figure 1) . The mixture was maintained in reflux, under stirring and inert atmosphere for 24 hours. Subsequently, the solid was separated by centrifugation and/or filtration and washed for 1-2 hours with toluene, in reflux. Finally, the catalysts X-CAT4, Y-CAT4 or Z-CAT4 were isolated by centrifugation and/or filtration and dried at 100-120°C.

The catalyst X-CAT9 displays an acidity of 0.7 mmol

Example 4: The catalysts X-CAT10, Y-CAT10 or Z-CAT10 were obtained by direct activation with chlorosulfonic acid (3.0 x 10^~2 mmol), in the presence of toluene or other non- hydrolytic solvent (40 mL) (see figure 1) . The mixture was kept at 0°C and, subsequently the chlorosulfonic acid was added dropwise. Afterwards, the mixture was stirred at ambient temperature for 5 hours. Finally, the catalysts X- CAT10, Y-CAT10 or Z-CAT10 were separated by filtration and/or centrifugation, washed several times with dichloromethane and dried at 100-120°C. The catalysts X- CAT10, Y-CAT10 and Z-CAT10 display an acidity of 6.0, 2.0 and 2.0 mmol H⁺/g_materiai respectively.

Example 5: X-CAT11, Y-CAT11 or Z-CAT11 (see figure 1) were prepared from the starting materials X-AlSi, Y-AlSi or Z- AlSi (2 g) by reaction of the starting materials X-AlSi, Y- AlSi or Z-AlSi with 1 , 2 , 2-trifluoro-2-hydroxy-l- trifluoromethyletane sulfonic β-sultone acid (4.34 mmol) in the presence of toluene or other non-hydrolytic solvent (80 mL) . The mixture was kept in reflux under magnetic stirring for 6 hours. The catalysts X-CAT11, Y-CAT11, Z-CAT11 were filtered and washed several times with dichloromethane and dried in a oven at 100°C for 24 hours. The catalysts X- CAT11 and Z-CAT11 display an acidity of 3.0 and 5.0 mmol H⁺/g_materiai respectively.

Example 6: The catalysts X-CAT12 , Y-CAT12 or Z-CAT12 (see figure 1) were prepared directly by activation with mineral acid. The starting materials X-AlSi, Y-AlSi or Z-AlSi (2 g) were dispersed in a solution of sulfuric acid (4 M) . Subsequently, the suspension was stirred at room temperature for 48 hours. Finally, the catalysts obtained were washed with water and methanol, filtered and/or centrifuged and placed in an oven at 120-150°C. The catalyst X-CAT12 displays an acidity of 0.4 mmol H⁺/g_materi_ai respectively .

All the catalysts prepared by the methods described in examples 1-6 were characterized by: Elemental analysis

(EA) , X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared attenuated total reflectance (FTIR- ATR) , X-ray diffraction (XRD) and pH at point zero charge

( pH_pz_c ) · The quantification of the Br0nsted acidity was obtained by acid-base titration (mmol H⁺/g_materiai ·

FAAEs production

Example 7: The production of FAAE was tested using 6 types of different raw materials. The raw materials (10 g or 100 g) , mixture of FFA and residues 1-5 (see Table 1), were placed in methanol or ethanol (10 - 100 mL) without any prior treatment and the catalysts (2-10% in relation to the raw material mass), prepared in examples 1-6, were added. The mixture was heated to 120°C, under continuous stirring and under pressure (4-20 bar), in a batch reactor (500 mL) . After 60 to 180 minutes, the reaction mixture was cooled to room temperature. The catalysts were separated from the reaction medium by filtration. The following table presents the catalytic results obtained, which were monitored by gas chromatography with FID detection, HPLC and by ¹H RMN.

(Na, Ca) 0.33 (Al,Mg) 2 (Si₄Oio) (OH) 2. -nH₂0 (designated herein X- AlSi), person having average knowledge in this field will be able to envisage many possibilities of modifying the same, without straying from the general idea, as defined in the claims. The preferred embodiments described above are obviously mutually combinable. The following claims additionally define preferred embodiments.

Lisbon, March 22, 2017.

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Claims

1. Heterogeneous catalysts based on mixtures of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having different Al/Si ratios comprising:

a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having the base formula

(Na, Ca) 0.33 (Al,Mg) 2 (Si₄Oio) (ΟΗ)₂.ΏΗ₂0 or Al₂Si₂0₅ (OH) ₄. Ώ¾0 or Nao.33 (Al,Mg) 2 (S14O10) (ΟΗ)₂.ΏΗ₂0, wherein n represents the number of H₂0 molecules;

and,

- a sulfonic group (-SO3H) .

2. Heterogeneous catalysts based on mixtures of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having different Al/Si ratios comprising:

a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having the base formula selected from (Na, Ca) 0.33 (Al,Mg) 2 (Si₄Oio) (ΟΗ)₂.ΏΗ₂0 or Al₂Si₂0₅ (OH) ₄. ΏΗ₂0 or Nao.33 (Al,Mg) 2 (S14O10) (ΟΗ)₂.ΏΗ₂0, wherein n represents the number of H₂0 molecules;

and,

- a sulfonic group (-SO₃H) .

3. Heterogeneous catalysts based on mixtures of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having different Al/Si ratios comprising:

a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having the base formula selected from (Na, Ca) 0.33 (Al,Mg) 2 ( S 14O10 ) (ΟΗ)₂.ΏΗ₂0 or Al₂Si₂0₅ (OH) ₄. ΏΗ₂0 or Nao.33 (Al,Mg) 2 ( S 14O10 ) (OH)₂.-nH₂0, wherein n represents the number of ¾0 molecules;

and,

and ,

- a sulfonic group (-SO3H) .

4. The heterogeneous catalysts as claimed in any of claims 1, 2 or 3, wherein the catalysts comprising a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having base formula (Na, Ca) 0.33 (Al,Mg) 2 ( S 14O10 ) (OH)₂.-nH₂0 present a surface area between 200 and 300 m²/g and an acidity between 0.4 to 6.0 mmol H⁺/g_material.

5. The heterogeneous catalysts as claimed in any of claims 1, 2 or 3, wherein the catalysts comprising a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having base formula AI2 S 12O5 (OH) ₄.71H2O present a surface area between 50 and 150 m²/g, and an acidity between 0.6 and 3.0 mmolH⁺/g_materiai ·

6 . The heterogeneous catalysts as claimed in any of claims 1, 2 or 3, wherein the catalysts comprising a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having base formula

Nao .33 (Al , Mg ) 2 ( S I4O10 ) (ΟΗ)2·-Π¾0 present a surface area between 50 and 100 m²/g, and an acidity between 2.0 and 5.0 mmol H⁺/g_material .

7. A method of preparing heterogeneous catalysts based on mixtures of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having different Al/Si ratios as defined in claim 1, comprising:

a silylation reaction between a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicate selected from (Na, Ca) 0.33 (Al,Mg) ₂ (Si₄Oi₀) (OH) ₂. nE₂0 or Al₂Si₂0₅ (OH) 4. ΏΗ₂0 or Na₀.33 (Al,Mg) 2 (S1₄O₁₀) (OH) 2. -nH₂0, and an organosilane selected from benzyltriethoxysilane, benzyltrichlorosilane, 4-biphenyliltriethoxysilane, 2- (4- chlorosulfonylphenyl ) ethyltrichlorosilane, 2- (4- chlorosulfonylphenyl ) ethyltrimethoxysilane, 3- mercaptopropyltriethoxysilane, 3- mercaptopropyltrimethoxysilane, 1- (naphthylmethyl ) trichlorosilane, 1- (naphthylmethyl ) triethoxysilane, 1- (naphthylmethyl ) trimethoxysilane, phenyltrichlorosilane, phenyltriethoxysilane, phenyltrimethoxysilane phenethyltrichlorosilane, phenethyltrimethoxysilane, 4- phenylbutyltrimethoxysilane and 4- phenylbutyltrichlorosilane ;

- oxidation of the intermediary compound obtained in the prior step with one or more oxidants selected from hydrogen peroxide (H2O2) , nitric acid (HNO₃) , potassium permanganate (ΚΜηθ₄) , potassium chromate (K₂Cr0₄) and sodium hypochlorite (NaCIO) .

8. The method of preparing heterogeneous catalysts as claimed in claim 7, wherein additionally occurs an acid activation step with a mineral acid selected from sulfuric (H₂S0₄) , phosphoric (H₃PO₄) , hydrofluoric (HF) , nitric (HNO3) , hydrochloric (HC1), chlorosulfonic (HSO3CI) and acetic acid (CH₃C0₂H) .

9 . The method for preparing heterogeneous catalysts based on mixtures of aluminium/silicon (Al/Si) oxides and/or aluminosilicates as defined in claim 1, comprising:

a silylation reaction between a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicate selected from (Na, Ca) 0.33 (Al,Mg) ₂ (Si₄Oi₀) (OH) ₂. nE₂0 or Al₂Si₂0₅ (OH) 4. ΏΗ₂0 or Nao.33 (Al,Mg) ₂ (S1₄O₁₀) (OH) ₂. ΉΗ₂0, and an organosilane selected from benzyltriethoxysilane, benzyltrichlorosilane, 4-biphenyliltriethoxysilane, 2- (4- chlorosulfonylphenyl ) ethyltrichlorosilane, 2- (4- chlorosulfonylphenyl ) ethyltrimethoxysilane, 3- mercaptopropyltriethoxysilane, 3- mercaptopropyltrimethoxysilane, 1- (naphthylmethyl ) trichlorosilane, 1- (naphthylmethyl ) triethoxysilane, 1- (naphthylmethyl ) trimethoxysilane, phenyltrichlorosilane, phenyltriethoxysilane, phenyltrimethoxysilane phenethyltrichlorosilane, phenethyltrimethoxysilane, 4- phenylbutyltrimethoxysilane and 4- phenylbutyltrichlorosilane ;

- acid activation of the intermediary compound obtained in the prior step with a mineral acid selected from sulfuric (H₂SO₄) , phosphoric (H₃PO₄) , hydrofluoric (HF) , nitric (HNO3) , hydrochloric (HC1), chlorosulfonic (HSO3CI) and acetic (CH₃CO₂H) acids.

10. A method for preparing heterogeneous catalysts based on mixtures of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having different Al/Si ratios as defined in claim 2, comprising:

direct acid activation of the mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicate selected from (Na, Ca) 0.33 (Al,Mg) ₂ (Si₄Oi₀) (OH) ₂. nE₂0 or Al₂Si₂0₅ (OH) ₄.ΏΗ₂Ο or Nao.₃₃ (Al,Mg) ₂ (S1₄O₁₀) (OH) ₂.ΏΗ₂Ο, with a mineral acid selected from sulfuric (H₂SO₄) , phosphoric (H₃PO₄) , hydrofluoric (HF) , nitric (HNO₃) , hydrochloric (HC1), chlorosulfonic (HSO₃CI) and acetic (CH₃C0₂H) acids.

11. A method of preparing heterogeneous catalysts based on mixtures of aluminium/silicon (Al/Si) oxides and/or aluminosilicates having different Al/Si ratios as defined in claim 3, comprising:

- a reaction between a mixture of aluminium/silicon (Al/Si) oxides and/or aluminosilicates selected from

(Na, Ca) 0.33 (Al,Mg) 2 (S14O10) ( ΟΗ)₂. ΏΗ₂0 or Al₂Si₂0₅ (OH) ₄. ΏΗ₂0 or Nao.33 (Al,Mg) 2 (S14O10) (OH)₂.-nH₂0, and an organic precursor selected from fluoro-alkyl-sultones , alkyl-sultones , benzyl alcohol and organosulfonates .

12. The method of preparing heterogeneous catalysts as claimed in claim 11, wherein additionally occurs an acid activation step with a mineral acid selected from sulfuric (H₂SO₄) , phosphoric (H₃PO₄) , hydrofluoric (HF) , nitric (HNO₃) , hydrochloric (HC1), chlorosulfonic (HSO₃CI) and acetic acids (CH₃C0₂H) .

13. The method as claimed in any of claims 7, 8 and 9, wherein a silylation reaction occurs in a non-hydrolytic solvent, carried out under inert atmosphere, at a temperature between 50 - 140°C, with a stirring period of 2-24 hours.

14. The method as claimed in any of claims 7, 8 and 9, wherein a silylation reaction is carried out at 120°C for 6 hours .

15. The method as claimed in any of claims 7 to 14, wherein the catalysts are separated from the reaction medium by centrifugation and/or filtration.

16. The use of the catalysts as defined in claims 1 to 6, in the production of fatty acid alkyl esters, by esterification and/or transesterification of free fatty acids and/or triacylglycerols and mixtures thereof and/or in catalytic reactions of hydrotreatment , condensation, alkylation, isomerization, dehydration, opening of epoxides, hydrolysis or aldol reactions.

Lisbon, March 22, 2017.