EP1390329B1 - Process for manufacturing microcrystalline paraffin - Google Patents

Description

The invention relates to a method for producing a microcrystalline paraffin.

Conventional petroleum derived microcrystalline paraffin (also known as microwaxes) consists of a mixture of saturated room temperature solid hydrocarbons having a chain length distribution of C ₂₅ to C ₈₀ . In addition to n-alkanes, the microcrystalline paraffins contain branched isoalkanes and alkyl-substituted cycloalkanes (naphthenes) as well as - albeit usually small - proportions of aromatics. The content of iso-alkanes and naphthenes ranges between 40 and 70% as determined by the EWF Standard Test Method for Analysis of Hydrocarbon Wax by Gas Chromatography. The quantitative dominance of isoalkanes (and naphthenes) determines their microcrystalline structure.

The solidification range is between 50 and 100 ° C according to DIN ISO 2207. The needle penetration has values between 2 x 10 ^-1 and 160 x 10 ^-1 mm according to DIN 51579. The solidification point and the needle penetration are used to distinguish between the microcrystalline paraffins between plastic and hard microcrystalline paraffins. Soft plastic microcrystalline paraffins (so-called petrolatum) are fast with pronounced adhesiveness and have solidification points of 65 to 70 ° C and penetration values of 45 to 160 x 10 ^-1 mm. The oil contents are between 1 and 15%. Plastic microcrystalline paraffins are readily malleable and kneadable and have solidification points between 65 and 80 ° C and penetration values of 10 to 30 x 10 ^-1 mm. The oil contents can be up to 5%. The hard microcrystalline paraffins are tough and weakly adhesive with solidification points of 80 to 95 ° C and penetration values 2 to 15 x 10 ^-1 mm. The oil contents amount to a maximum of 2% (see Ullmann's Encyclopedia of Industrial Chemistry, VCH Verlagsgesellschaft 1996 ).

Microcrystalline paraffins have a high molecular weight and thus high boiling points. They are so far from the residues of vacuum distillation of petroleum, especially in the production of lube oil (residue waxes), as well as from the precipitation of petroleum in its promotion, its transport and its storage won, in technologically very complex and costly process with several Stages, for example deasphalting, solvent extraction, dewaxing, de-oiling and refining. The de-oiled microcrystalline paraffins contain sulfur, nitrogen and oxygen compounds as impurities. They are therefore not completely odorless and have a dark yellow to dark brown color. The refining required therefore takes place depending on the later use by bleaching (technical applications) or by hydrorefining (applications in the food and pharmaceutical industries).

Microcrystalline paraffins are mainly used as a mixture component in paraffin or wax mixtures. The use is usually in areas up to 5%. In particular, the hardness and melting point of these mixtures should be increased and flexibility and oil-binding improved. Typical applications include, for example, the manufacture of waxes for impregnation, coating and laminating for the packaging and textile industries, heat seal and hot melt adhesives, and pharmaceutical and cosmetic products, including chewing gum. Furthermore, they are used in potting and cable compounds as well as plastics in general but also in the candle, rubber and tire industries as well as in care, anti-slip and corrosion protection agents.

From the DE 69 418 388 T2 is a hydroisomerization of room temperature solid n-paraffins with more than 15 carbon atoms with the use of a catalyst on the basis of a Group VIII metal, in particular platinum, and a boron silicate having a structure of β-zeolites to products which are suitable for the production of lubricating oils. (Page 1)

Specifically, the following zeolites were named: Omega zeolite, ZSN-5, X zeolite, Y zeolite and other zeolites.

In the DE 695 15 959 T2 describes the hydroisomerization of waxy feedstocks into products suitable for the production of lubricating oils. In this case, a temperature of 270 ° to 360 ° C and a pressure of 500 to 1500 psi or 3.44 MPa to 10.36 MPa applied. The catalyst is based on a catalyzing metal component on a porous, heat-resistant metal oxide support (see page 2, paragraph 1), in particular 0.1 to 5 wt .-% of platinum on alumina or zeolites, such as Offretit, zeolite X, Zeolite Y, ZSM -5, ZSM-2, etc. (see page 3, center). The feed to be isomerized may be any wax or waxy material, especially a Fischer-Tropsch wax (see page 5, center). The hydrogen is fed to the reactor at a rate of 1,000 to 10,000 SCF / bbl and the wax at 0.1 to 10 LHSV (see page 6, center). The isomerization product is liquid (see page 7, line 7). It can be fractionated by distillation or by treatment with solvents, eg with an MEK / toluene mixture (see page 7, last paragraph).

The entire liquid product from the isomerization unit is more advantageously treated in a second stage under mild conditions using the Group VIII noble metal isomerization catalyst and a refractory metal oxide to reduce PNA and other impurities in the isomerate and thus an improved oil To provide daylight resistance (see page 8, paragraph 2). Under mild conditions are meant: A temperature in the range of about 170 ° to 270 ° C, a pressure of about 300 to 1500 psi, a hydrogen gas rate of about 500 to 1000 SCF / bbl and a flow rate of about 0.25 to 10 vol./vol./hr.

In the DE 38 72 851 T2 is the preparation of a middle distillate fuel from a paraffin wax, in particular a FT wax (see claim 2) described, wherein the wax under hydroisomerization conditions in the presence of a specific catalyst based on a metal of the VIII. Group, in particular platinum (claim 12), and aluminum oxide as support material is treated with hydrogen to give a middle distellite product and a bottom product having an initial boiling point above 371 ° C (see claim 1), in particular a low pour point lube oil fraction (see Claim 5). The wax is fed to the reactor at a rate of 0.2 to 2 V / V. The hydrogen is fed to the reactor at a rate of about 0.089 to 2.67 m3 H2 per 11 of wax. The catalyst has a decisive influence on the transformation. When it is based on platinum and a β-zeolite having a pore diameter of about 0.7 nm, the desired conversion to a middle distillate product is not observed, especially as the temperature decreases to 293.9 ° C. (see Example 3).

From the WO 01/74969 A2 For example, a process for hydroisomerization of FT paraffin is known using a zeolite based catalyst. The US-A-4419220 describes the conversion of paraffin fractions in a liquid starting product by hydroisomerization and optionally cracking to liquid fractions. The catalyst used is based on a B-zeolite and a metal of group VIII A. Die EP 435619 A1 describes the conversion of FT paraffin to a low melting point lubricant by hydroisomerization. It is a titanium-based catalyst with a metal of VIII. Subgroup used as hydrogenation.

In contrast, the invention has the object to provide a novel method for producing a microcrystalline paraffin.

This object is achieved in the subject matter of claim 1. In this connection, it is stated that the microcrystalline paraffin is prepared by catalytic hydroisomerization at temperatures of 200 ° C. -300 ° C. from paraffins (FT paraffins) obtained by Fischer-Tropsch synthesis with a C chain length distribution in the range from C ₂₀ to C ₁₀₅ becomes.

Surprisingly, it has been found that such a microcrystalline paraffin is free from naphthenes and aromatics. It is further surprising that, despite isomerization, crystallinity has been preserved. Continuous production with defined properties is possible. There is provided a microwax product in the low and high solidification point range. Continuous or discontinuous catalytic hydroisomerization of Fischer-Tropsch paraffins (FT paraffins) can be carried out. With regard to FT paraffins as such, particular reference is made to the statements made by A. Kühnle in Fette. Soap. Paint, Volume 84, pages 156 ff. "Fischer-Tropsch waxes synthesis, structure, properties and applications". Briefly, the FT paraffins are paraffins prepared by the Fischer-Tropsch process in a known way from synthesis gas (CO and H2) in the presence of a catalyst at elevated temperature. They represent the highest-boiling fraction of the hydrocarbon mixture. The result is essentially long-chain, less branched alkanes, which are free of naphthenes and aromatics and of oxygen and sulfur compounds.

Such FT paraffins with a high proportion of n-paraffins and a C chain length in the range of C ₂₀ to C ₁₀₅ are converted by the method described here to high-melting, microcrystalline paraffins with a high proportion of iso-paraffins.

1. A. Einsatz von FT-Paraffin als Ausgangsmaterial
   1. a) mit einer C-Kettenlänge im Bereich von C₂₀ bis C₁₀₅,
   2. b) vorzugsweise mit einem Erstarrungspunkt im Bereich von 70 bis 105°C, insbesondere ca. 70, 80, 95 oder 105 ° C nach DIN ISO 2207,
   3. c) einer Penetration bei 25° C von 1 bis 15;
   4. d) einem Verhältnis von iso- zu n-Alkanen von 1 : 5 bis 1 : 11
2. B. Verwendung eines Katalysators, vorzugsweise in Form von Extrudaten, Kugeln, Tabletten, Granulaten oder Pulvern, zweckmäßigerweise auf der Basis von
   1. a) 0,1 bis 2,0, insbesondere 0,4 bis 1,0 MA.-%, bezogen auf den bei 800°C geglühten Katalysator, an hydrierendem Metall der achten Nebengruppe, insbesondere Platin, sowie
   2. b) eines Trägermaterials aus einem β-Zeolithen mit einem Porendurchmesser im Bereich von 0,5 bis 0,8 nm (5,0 bis 8,0 Å),
3. C. Anwendung einer Prozess-Temperatur von 230 bis 270°C,
4. D. Anwendung eines Drucks von 2,0 bis 20,0, insbesondere von ca. 3 bis 8 MPa in Gegenwart von Wasserstoff und einem Verhältnis von Wasserstoff zu FT-Paraffin von 100 : 1 bis 1000 : 1, insbesondere etwa 250 : 1 bis 600 : 1 Nm³ / m³.

The microcrystalline paraffin can be prepared by catalytic isomerization according to the process aspect of the invention as follows:

1. A. Use of FT paraffin as starting material
   1. a) having a C chain length in the range of C ₂₀ to C ₁₀₅ ,
   2. b) preferably with a solidification point in the range of 70 to 105 ° C, in particular about 70, 80, 95 or 105 ° C according to DIN ISO 2207,
   3. c) a penetration at 25 ° C from 1 to 15;
   4. d) a ratio of iso to n-alkanes of 1: 5 to 1: 11
2. B. Use of a catalyst, preferably in the form of extrudates, spheres, tablets, granules or powders, advantageously based on
   1. a) 0.1 to 2.0, in particular 0.4 to 1.0 MA .-%, based on the annealed at 800 ° C catalyst, to hydrogenating metal of the eighth subgroup, in particular platinum, and
   2. b) a carrier material of a β-zeolite having a pore diameter in the range of 0.5 to 0.8 nm (5.0 to 8.0 Å),
3. C. application of a process temperature of 230 to 270 ° C,
4. D. Application of a pressure of 2.0 to 20.0, in particular of about 3 to 8 MPa in the presence of hydrogen and a ratio of hydrogen to FT paraffin of 100: 1 to 1000: 1, in particular about 250: 1 to 600: 1 Nm ³ / m ³ .

Conveniently, the loading of the reactor with the FT paraffin is in the range of 0.1 to 2.0, especially 0.2 to 0.8 v / v. h (volume of FT paraffin per volume of the reactor within one hour).

The yield of hydroisomerates is between 90 and 96% by mass, based on the particular FT paraffin used. The resulting hydroisomerates still contained alkanes in the C chain length range <= with respect to low-melting alkanes C ₂₀ up to 5% (usually up to 3%). These alkanes could be easily separated by vacuum distillation with steam.

Preferably, the catalytic hydroisomerization of the FT paraffins is carried out continuously in a flow-through reactor with a fixed catalyst, in particular in the form of extrudates, spheres or tablets, the reactor being oriented vertically, as desired, both top to bottom and from bottom to top can be flowed through. The process may also be discontinuous in e.g. a stirred autoclave be carried out in a batch process, wherein the catalyst is contained in a permeable network or finely divided is used as granules or powder in FT paraffin. The process parameters of the continuous as well as the discontinuous process are the same.

• Verglichen mit den eingesetzten FT-Paraffinen haben sie niedrigere Erstarrungspunkte und enthalten neben n-Alkanen einen hohen, insbesondere höheren Gewichtsanteil an iso- als an n-Alkanen. Der Anteil an n-bzw. iso-Alkanen wird durch die Gaschromatografie bestimmt. Der durch die Hydroisomerisierung erreichte erhöhte Isomerisierungsgrad findet seinen Ausdruck in erhöhten Penetrationswerten, einem verringerten Kristallisationsgrad und einer abgesenkten Schmelzenthalpie. Außerdem weisen diese Produkte eine pastöse bis zähklebrige Konsistenz auf bei etwas krümeliger Erscheinungsform.

The microcrystalline paraffins obtained according to the invention have the following properties:

• Compared with the FT paraffins used, they have lower solidification points and, in addition to n-alkanes, contain a high, in particular higher, weight fraction of isothene than n-alkanes. The proportion of n-resp. Iso-alkanes is determined by gas chromatography. The increased degree of isomerization achieved by the hydroisomerization finds expression in increased penetration values, a reduced degree of crystallization and a reduced enthalpy of fusion. In addition, these products have a pasty to viscous consistency on something crumbly appearance.

The degree of crystallinity is determined by an X-ray diffraction analysis. It denotes the crystalline content in the product obtained in relation to the amorphous share. The amorphous portions lead to a different diffraction of the X-rays than the crystalline portions. The needle penetration at 25 ° C in the products of the invention is in the range of 20 to 160, measured according to DIN 51579. The products obtained are solid at 20 ° C, in the sense that they do not run.

The crystalline fraction is reduced in particular as follows: While the starting material, a crystalline content in a range of 60 to 75% occurs, is observed in the hydroisomerizate such from 30 to 45%. Especially in the range of 35 to 40 (36,37,38,39)%.

The crystalline fractions and the amorphous fractions are indicated by the aforementioned X-ray diffraction analysis in each case in MA.%.

The microcrystalline paraffins produced according to the invention from FT paraffins have physical and material properties which are similar or comparable to those of petroleum-based microcrystalline paraffins (microwaxes).

• Nadelpenetration: von 1 x 10^-1 bis 7 x 10^-1, insbesondere 3 x 10^-1 bis 6 x 10^-1 mm, bestimmt nach DIN 51579,
• Ölgehalt: 1,0 bis 2 Gew.-% insbesondere 1,2 bis 1,6 Gew.-%, bestimmt durch MIBK nach modifizierter ASTM D 721/87
• Erstarrungspunkt: ca. 60 bis ca. 95°C, insbesondere 70 bis 85 °C, bestimmt nach DIN ISO 2207.

The microcrystalline paraffins produced by catalytic hydroisomerization can also be deoiled with a solvent. However, this does not say that the hydroisomerization products described have a content of conventional oil. In any case, very short-chain n- or iso-alkanes are removed. When using a solvent mixture of dichloroethane: toluene of 95: 5 parts by volume and a product-solvent ratio of 1: 3.6 parts at 22 ° C, a deoiled microcrystalline paraffin in a yield of 80 to 90 wt .-%, based on the Hydroisomerate, obtained. It has the following characteristics It has the following characteristics:

• Needle penetration: from 1 × 10 ^-1 to 7 × 10 ^-1 , in particular 3 × 10 ^-1 to 6 × 10 ^-1 mm, determined to DIN 51579,
• Oil content: 1.0 to 2% by weight, in particular 1.2 to 1.6% by weight, determined by MIBK according to modified ASTM D 721/87
• Freezing point: about 60 to about 95 ° C, especially 70 to 85 ° C, determined according to DIN ISO 2207.

Removing the oil turned the medium-hard product into a tough product when compared to the petroleum-based ones. Then the de-oiled hydroisomerizate is comparable to the hardest petroleum-based types.

Because of its properties, the microcrystalline hydroisomerate prepared according to the invention and the corresponding deoiled microcrystalline hydroisomerizate, such as a microwax, can be used (see introduction). In particular, the resulting hydroisomerizate can also be oxidized. There are obtained oxidized products, which differed by melting range and degree of oxidation and are used mainly as corrosion inhibitors and as a cavity and underbody protection for motor vehicles. They are also used in emulsions as care and release agents and as an additive for printing and carbon paper colorants.

The acid and ester groups, which are statistically distributed over hydrocarbon chains, can be reacted with inorganic or organic bases to form water-dispersible formulations (emulsifying waxes) and lead to products with very good metal adhesion.

Further fields of application are the production of impregnating, coating and laminating waxes for the packaging and textile industry. Heat sealants and hot melt adhesives as blend components in candles and other wax goods in wax mixtures for paint, floor and car care products as well as for dental technology and pyrochemistry.

They are also part of sunscreen waxes for the tire industry electrical insulation materials scaffolding and model waxes for the investment casting industry and wax formulation for the explosives, ammunition and Treibstatztechnik.

Furthermore, such products are suitable as release agents in the pressing of wood, chipboard and fibreboard in the manufacture of ceramic parts and because of their retention capacity for the preparation of solvent-based care products, grinding and polishing pastes and matting agents for paints.

Furthermore, these products can be used for the formulation of adhesive waxes, cheese waxes, cosmetic preparations, chewing gum bases, cast and cable compounds, sprayable pesticides, vaselines, artificial chimney logs, lubricants and hot melt adhesives.

An examination for food authenticity is made, for example, according to FDA, § 175. 250.

The invention will now be explained in detail by way of examples.

Example 1:

An FT paraffin having a solidification point at 97 ° C was catalytically isomerized with hydrogen at a pressure of 5 MPa (50 bar), a temperature of 270 ° C and a v / vh ratio of 0.3. The occurred hydroisomerization was confirmed by the data in Table 1.

The hydroisomerizate is white, odorless and slightly sticky and thus differs significantly from the brittle-hard feedstock. The isoalkane content is increased by about 6-fold, which is due to the increased penetration value, the decreased crystalline proportion and the reduced enthalpy of fusion is occupied. The synthetic microcrystalline paraffin thus prepared is classified according to its characteristics between a plastic and a hard micron oil based on petroleum With the hydroisomerisate thus a paraffin was obtained with pronounced microcrystalline structure whose C-chain length distribution based on the carbon atoms with 23 to 91 in about that of the starting material with 27 to 95, but just shifted towards smaller chain lengths, corresponds. The chain length was determined by gas chromatography.

Example 2:

An FT paraffin having a solidification point at 70 ° C was catalytically isomerized with hydrogen at a pressure of 5 MPa (50 bar), a temperature of 250 ° C and a v / vh ratio of 0.3. The structural change that occurred was confirmed by the key figures in the table.

The hydroisomerizate is white and odorless as well as pasty and slightly sticky. The isoalkane content is increased by about 5-fold. The high degree of isomerization finds expression in the significantly increased penetration value, the reduced crystalline content and the reduced enthalpy of fusion. The resulting microcrystalline paraffin has a similar but slightly smaller C chain length than the FT paraffin, as evidenced by the carbon atoms: 23 to 42 in the hydroisomerate and 25 to 48 in the FT paraffin. The resulting synthetic microcrystalline paraffin is comparable to a petroleum based soft plastic microcrystalline paraffin according to its characteristics.

Examples 1 and 2 show that the FT-paraffins, which consist predominantly of n-alkanes and have a finely crystalline structure and a brittle-hard consistency, in the non-flowing, pasty or solid paraffins that have lower melting temperatures than the feeds. These paraffins are characterized by a high content of branched alkanes and consequently have a microcrystalline structure with a significantly reduced degree of crystallization and a plastic to slightly sticky consistency. The branched alkanes are predominantly methylalkanes, with the methyl groups preferably occurring in the 2, 3, 4 or 5 position. To a lesser extent methyl branched alkanes were formed several times.

The results of Examples 1 and 2, compared with the starting material are summarized in the attached Table 1.

Example 3:

A catalyst (cylindrical extrudate, diameter 1.5 mm, length about 5 mm) was used without comminution. Into the reactor tube (total volume 172 ml, inner diameter 22 mm) 92 ml of catalyst were fed undiluted. The catalyst zone was also overcoated with the earth material. A thermocouple was positioned in the reactor so that the temperature was measured at a depth of 2 cm and 17 cm of catalyst bed. The catalysts were dried and activated (by high temperature, water is expelled and platinum is reduced).

The paraffin feed used was an FT paraffin C80 (solidification point 81 ° C., mass ratio n- / iso-paraffins: 93.9 / 6.1). The oil content of the starting product was 0.5%. The needle penetration value 6.0.

The experiments were carried out at a hydrogen pressure of 50 bar.

The following results were obtained: At 260 ° C and 0.96 v / vh, the iso fraction (MA.%) Increased from 6.1 (FT paraffin) to 42 (hydroisomerate). The solidification point was 77 ° C, the oil content 18.8%. The needle penetration value 32.

The catalyst was a platinum catalyst on β-zeolite. β-zeolites is referred to the reference " Atlas of Zeolites Structure Type ", Elsevier Fourth Revised Edition, 1996 , pointed out.

Gas chromatograms obtained for this example are attached as an annex.

In contrast to the microcrystalline paraffins obtained from the petroleum, the fully synthetic microcrystalline paraffins produced by the hydroisomerization according to the invention contain no strongly branched isoalkanes, no cyclic hydrocarbons (naphthenes) and in particular no aromatics and sulfur compounds. They therefore meet the highest purity requirements for microcrystalline paraffins, making them ideally suited for use in the cosmetics and pharmaceutical industries as well as for packaging and preservation in the food industry. Table: Characteristic values of starting materials and reaction products characteristics unit Measurement Method example 1 Example 2 FT paraffin Hydroiso-merizate FT paraffin Hydroiso-merizate Freezing point ° C DIN ISO 2207 97.0 86.5 71.5 61.5 Penetration N at 25 ° C 0.1 mm DIN 51579 2 42 13 98 Schmelzenthalpine J / g ASTM D4419 221 127 195 120 crystalline parts MA .-% X-ray diffraction analysis 70.7 43.5 62.4 38.8 Weight ratio n / isoalkanes % gas chromatography 88/12 37/63 91/9 43/57 Oil content (MIBK) MA .-% ASTM D721-87 (modified) 0.66 14.6 0.4 23.1

Claims (9)

1. Process for the preparation of a microcrystalline paraffin, by catalytic hydroisomerization by

   A. use of FT paraffins as starting material having carbon atoms in the range from 20 to 105 and

   B. use of a catalyst and

   C. action of pressure in the presence of hydrogen,

   characterized in that a catalyst is used that is based on a ß-zeolite having a pore size between 0.50 and 0.80 nm, as support material and having a metal of the 8th subgroup as active component, that a process temperature of from 200 to 300°C is used, at a pressure from 2 to 20 MPa and a feed ratio of hydrogen to FT paraffin of from 100 : 1 to 1 000 : 1 Nm³ per m³.
2. Process according to Claim 1, characterized in that the pressure is from 3 to 8 MPa.
3. Process according to either of Claims 1 and 2, characterized by a process temperature of from 230 to 270°C.
4. Process according to any of Claims 1 to 3, characterized by a feed ratio of hydrogen to FT paraffin of from 250 : 1 to 600 : 1 Nm³ per m³.
5. Process according to any of Claims 1 to 4, characterized in that a loading of from 0.1 to 2.0 v/v.h, preferably from 0.2 to 0.8 v/v.h, is used.
6. Process according to any of Claims 1 to 5, characterized in that the catalyst has a pore size between 0.55 and 0.76 nm.
7. Process according to any of Claims 1 to 6, characterized in that the catalyst has platinum as hydrogenation metal.
8. Process according to Claim 7, characterized in that the platinum content of the catalyst is from 0.1 to 2.0% by mass, preferably from 0.4 to 1.0% by mass, based on the catalyst calcined at 800°C.
9. Process according to any of Claims 1 to 8, characterized in that the FT paraffin is used in a solidification point range of from 70 to 105°C, preferably with solidification points of 70, 80, 95 or 105°C.

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