JPS6032605B2 - A practical method for separating large amounts of unsaturated compounds from liquid paraffinic hydrocarbon mixtures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a purification process for virtually complete separation of unsaturated compounds from liquid hydrocarbon mixtures whose components have only slight physicochemical differences from one another.

The present invention relates in particular to an improved process for separating aromatic hydrocarbons from hydrocarbon mixtures containing primarily paraffins.
The separation of unsaturated compounds from paraffinic hydrocarbon mixtures is known and is conventionally carried out by treating the crude hydrocarbon mixture with a liquid, such as concentrated sulfuric acid, or with a selective solvent, such as liquid sulfur dioxide, furfurol, etc.

However, in order to achieve a practically complete separation of unsaturated compounds, the known purification processes require considerable expense and, for economic reasons, are often used only for the crude purification of crude hydrocarbon mixtures. As is well known, liquid hydrocarbon mixtures which still contain only a minor component of unsaturated compounds can be further purified in an economical manner by treatment with solid adsorbents.

In this way, for example German patent application P2252305
．． 3, a method for producing purified n-paraffin is known,
In this method, carcinogenic polycyclic aromatic hydrocarbons are extracted from industrially obtained n-paraffin mixtures by treatment with a certain aluminum oxide adsorbent, and the purified n-paraffins are used for the production of biogen protein for food. Remove as much as possible. In this method, a crude n-paraffin mixture is passed through a solid bed of adsorbent. However, it is difficult and expensive to completely remove the aromatic compounds bound to the adsorbent again and regenerate it for new use. US Patent No. 3,409,691 (or equivalent Belgian Patent No. 693,481, Dutch Published Patent No. 6,701,346, British Patent No. 1
161773 or German Published Patent No. 16182
Another method, described in US Pat. No. 6,335,039, uses a macroporous dehydrated cation exchanger resin as a selective adsorbent in the form of its metal salts to separate mixtures containing substances of various polarities. Use as.

However, the separation of polycyclic aromatic compounds, which are present in only a small proportion in a raw material consisting primarily of higher paraffins, is, however, described in the U.S. patent specification as well as the economical regeneration of the exchanger resins utilized. Not listed. Luxembourg Patent No. 62 No. 5 discloses a method by which polycyclic aromatic substances and other harmful substances can be removed from crude petroleum paraffin (slack wax) by adsorption using the molecular rings of zeolite. It is publicly known. DE 23 64 333 describes a method for the purification of petroleum paraffin (slack wax), in which the liquefied raw material is primarily completely loaded with metal ions, in particular silver or steel ions. and also preferably with a macroporous dehydration exchanger resin disposed in the column as a solid layer. This process yields a product which complies with the purity requirements of the German Pharmacopoeia Act, Skin Edition, and is therefore suitable for the synthesis of biogen proteins, for medicinal and cosmetic purposes, and for the food industry, but the exchanger resin used for the separation is is relatively troublesome to play. This is because the exchanger resin is washed with an inert hydrocarbon, then treated with an alcohol-ether or ketone to desorb the separated aromatics, and finally washed once again with an inert hydrocarbon. This is because it must be dried. From German Patent Publication no.
(according to the specification), the unsaturated compounds of the exchanger resin are desorbed and eliminated in the liquid phase with gaseous hydrocarbons under normal conditions at temperatures of 10 to 40 qo and pressures above atmospheric pressure of 1 to 3 hydrophobic pressures. Methods of simplifying the process by doing this are known.

Liquefied propene or putene is used in particular as adsorbent. In this process, the exchanger resin that served to separate the unsaturated compounds is simply washed once more with an inert hydrocarbon and subsequently degassed with a liquefied olefin. The desorbent is then evaporated. This eliminates the need for a second cleaning treatment of the exchanger resin. However, the disadvantage is that this process has to be carried out at pressures above atmospheric pressure, and the liquefied olefins used for desorption sometimes have a tendency to form polymers, which impair the regeneration properties of the exchanger resin. It is something that can be interfered with. The object of the present invention is to virtually completely separate unsaturated compounds, in particular polycyclic aromatic hydrocarbons, from paraffinic hydrocarbon mixtures by treatment with macroporous dehydrating cation exchanger resins in the form of metal salts. The objective is to further simplify and improve the method. The object of the present invention is to remove unsaturated compounds from paraffinic liquid hydrocarbon mixtures whose components have only slight physicochemical differences using macroporous dehydrated enteric ion exchanger resins in the form of silver or copper salts. The process involves the actual separation of large amounts of unsaturated compounds by processing and producing a hydrocarbon product in which the unsaturated compounds are actually completely liberated. It is characterized in that the desorption of the ion exchanger resin is carried out by passing mononuclear aromatic hydrocarbons under standard pressure at a temperature of 50 to 150 qC. The ion exchange resin used in the method of the present invention has a specific surface area and porosity within a certain range, and has a specific surface area and a porosity within a certain range.
It is a sulfonated styrene/divinylbenzene copolymer type cation exchange resin loaded with valence ions.

According to the invention, the specific surface area is preferably between 40 and 1000〆/
g, preferably from 500 to 750/g, and an average diameter of the pores from 20 to 250 Δ, preferably from 40 to 60 A, is used. As has been found, the use of mononuclear aromatic solvents, such as benzol, toluol, xylol, etc., for desorbing exchanger resins loaded with unsaturated compounds, as described in German Patent No. 2364306 and German Published Application No. 23 The known method from No. 333 can be simplified.

This utility is due to the fact that macroporous dehydration cation exchange resins of aromatic hydrocarbons, in particular their adsorption binding to silver and steel salts, are known and also for the separation of aromatic unsaturated compounds from hydrocarbon mixtures. It is amazing as long as you use it to do so. In particular, since higher polycyclic aromatic compounds bind relatively tightly to the salts of such enteric ion exchanger resins, it could not be foreseen that they could be desorbed and eliminated by mononuclear aromatic substances. . Second, even though the elimination of higher aromatics is achieved by the lower aromatics of the desorbent, the desorbent binds to the exchanger resin and is sufficiently removed from this by routine cleaning treatments with lower aliphatic hydrocarbons. I had to expect that I couldn't do it. It has surprisingly turned out that this fear is unfounded and that mononuclear aromatic substances such as benzol, toluol, xylol, etc. are perfectly suitable as desorbents. The enteric ion exchanger resin, which is preferably used as a solid phase in separation columns and the like, can be purified in the conventional manner before desorption by washing with aliphatic hydrocarbons, such as isooctane and the like. In the same way, the desorbent can be liberated from the cation exchanger resin desorbed according to the invention by washing with aliphatic hydrocarbons and used in a new separation step. However, as will still be shown in the following examples, one or two of these washing steps can be omitted without significantly reducing the separation result. A particularly simple implementation of the method according to the invention is
Omitting the washing of the enteric ion exchanger resin with aliphatic hydrocarbons before and after the desorption process and simply removing the major amount of desorbent remaining in the resin after desorption from the cation exchanger resin with nitrogen or other inert gas It is about ejecting through communication. The exchanger resin treated in this way can be used directly for the fresh separation of unsaturations, especially aromatics, from fresh feedstock. Of course, with this greatly simplified method of operation, it is not possible to avoid the presence of desorbent residues in the purified product.

For example, Parafinum liquiidum (ParaH
liquidum) or solid paraffin (Pa.
In order to obtain a pure n-paraffin mixture suitable for the production of raHinmmdmwm) or Biogen proteins, the presence of a minor component of the desorbent in the separation product is not a significant disadvantage. This is because such pure paraffin products have significantly higher boiling points than the desorbents according to the invention. Aromatic desorbents are used and also aliphatic desorbents are used, since desorbents that have entered the product, such as benzol, toluol, xylol, etc., can easily be removed from this by a desorption process, preferably by passing water vapor. Despite the omission of the washing treatment with hydrocarbons, in the process according to the invention the content of aromatic hydrocarbon compounds completely complies with the German Pharmacopoeia Act, Second Edition (DAB plate) or is present below the limit values. A paraffin product can be obtained. Next, the present invention will be explained in detail with reference to examples.

The bulk separation of aromatics and other polar impurities is demonstrated in three purification steps: 1. Purification of deoiled paraffin slack wax. 2. Production of Paraffinum liquidum (Pa is ffinum liquidmm) from hydrogenated white oil. 3. Molecular muscle. Due to the limited absorption capacity for unsaturated compounds of enteric ion exchanger resin adsorbents for the purification of n-paraffins produced using the urea method or the urea method, Parafinum liquidium
), the aromatics content of the starting material is reduced by hydrogenation (from crabmeat).

In pure purification of slack wax from cold deparaffinization, this can be achieved by deoiling. If the aromatics content is high, the adsorbent must often be regenerated. This reduces the amount of resin left unused. N-paraffin from molecular muscle or deparaffinization with urea can be used without pretreatment.

In an example, the exchanger resin, Amberite XE284, is a macroporous dehydrated intestinal ion exchanger resin.
It has a silver content of 25-27% by weight based on the dry resin and a surface area unevenness of the dry resin of 0-440〆/g [Brunauer (
Br skin a crotch r), measured in N2 by the method of Emmet and Teller]. The experiment was conducted using an adsorption tower in which the charge material was introduced from the bottom to the top.

After the adsorption has ended, the rhododendrons are removed from the adsorption resin with saturated hydrocarbons and subsequently removed with mononuclear aromatics, or the desorption is carried out directly without a washing step. Fresh adsorption is coupled with saturated hydrocarbons either directly for desorption or under intermediate treatment in the washing step. Parafinum liquidium (Paraffinumliquid mountain), Paraffinium durum
) and n-paraffins are listed in Table 1.

As a desorbent, toluene was used at a temperature of 9000 and a liquid hourly space velocity of 0.9/resin 1. Use in hr. Washing is carried out with a saturated hydrocarbon, in this case i-octane. The use of aromatic substances as desorbents has the advantage that the shelf life of the exchanger resin is significantly extended.

In the case of the ketone desorbents used, reactions occur in which military condensates are formed, which reduce the adsorption properties of the exchanger resin and weaken its capacity. In this way, the capacity of the resin is already 50% of its full capacity after 10 steps (adsorption/desorption) when using ketones as desorbents. In contrast, when mononuclear aromatics are used as desorbents, the capacity of the resin is still 75% after 10 steps. Tables 2, 3 and 4 show the results obtained with the present process for bulk separation of unsaturated compounds from liquid hydrocarbon mixtures.

The n-paraffins from Table 4 are particularly suitable as feedstock for protein production. Table 5 shows the commonly used operating methods (adsorption, washing, desorption,
It has been shown that no reduction in separation efficiency occurs compared to washing). The operating conditions correspond to those in Table 1. Process 1
Steps 3 to 3 are performed without cleaning with saturated hydrocarbons (adsorption/desorption only), and steps 4 to 6 are performed without cleaning (adsorption/desorption/desorption).
washing). The entire process was carried out continuously without changing the resin. Steps 1-3 actually show the same throughput efficiency compared to steps 4-6.

This clearly demonstrates that the method works with and without a washing step as required. Ultraviolet absorbance at 27 meters was used as a measure of the amount of aromatic substances in the crystalline substances and the final product.

For feed materials with an absorption of more than 1 UV radiation, the values were determined after dilution with i-octane and subsequently converted.

The amount of sulfur was measured using crab light X-rays.

Experimental results show that the method is particularly preferably used for separating trace amounts of aromatic substances. An excellent range of use is an aromatic content of 500 kg or less. The amount of purified product per step is inversely proportional to the concentration of aromatics for the same capacity for aromatics. Table 1.

Conditions Table 2: Production of Parafinum liquidium (light).

The Hishiri substance is extracted twice from spindle oil distillate (boiling point:
400-450 qo) by acidifying with fuming sulfuric acid (S0320%). Three types of white oils with different concentrations of aromatic substances (expressed in terms of ultraviolet absorption according to the 27 m law, since the layer thickness of the glass dish is 0.5 cm) were used. Compared to adsorption treatment, the corresponding oil used was treated with fuming sulfuric acid (
Several conventional treatments with 20% S03) were carried out, each time with 7% oleum, up to the specification with DAB skin.

1) Results in the fifth step Table 3: High purity Parafinium durum (Pa
production of raffinumdmmm).

Bagged material: Slack wax (SAE class 5 solvent neutral oil), pretreated with Tomil 0.5% by weight;
Oil content 2-3% by weight. On average, 14k9/ in 10 steps
Pure paraffin/X9 resin and process were processed.

The feed material and final product had the following analytical data:
Acceptable absorption up to 0.6 by the DAB dish was not available.

This is because at E=0.25 or higher, the required sulfuric acid reaction (due to DAB skin) is not relevant to the specifications. Table 4 Purification of n-paraffins from the Molecular Section Method.

n-Paraffin 3 is more effective than fuming sulfuric acid (1
04.5% day 2S04) treated with 33% by weight, the absorption was 0.45 at 27 Mm (1 glass plate) for the treated product.
Met.

Table 5: Production of Paraphinium liquidium (PL).

Bagged material as in the example in Table 2, but with a small amount of aromatic substances (see white oil 1).

Product after dearomatization: Absorption at 27 m (0.5) = <0.8 (corresponding to DAB skin of PL) Steps 1 to 3:
Steps 4 to 6 without a washing step: The method according to the invention with washing before and after desorption preferably has a specific surface area of 40 to
It is carried out with an enteric ion exchanger resin having a loo0m/g and an average pore size of 20-250A.

Particularly good values were shown for exchanger resins with a specific surface area of 500-750/g and a pore size of 40-60 A. Additional related invention, Patent No. 1258055 (Japanese Patent Publication No. 59-3
No. 1486) removes unsaturated compounds from liquid hydrocarbon mixtures containing unsaturated compounds in which the components of the mixture have only slight physicochemical differences or contain only traces of unsaturated compounds. , quantitative separation of unsaturated compounds using an enteric ion exchanger loaded with metal ions and having a specific surface area of at least 1/g and a pore diameter >10A, in which unsaturated compounds are separated by monovalent ions of silver or copper. The macroporous dehydrated intestinal ionic symbiotic resin loaded with 100 ml of macroporous gas was combined with a macroporous dehydrated ionic resin and subsequently catalyzed in the liquid phase with gaseous hydrocarbons under standard conditions at a temperature of 10 to 400 C and an overpressure of 1 to 3 tm. The present invention relates to a method for quantitatively separating unsaturated compounds from a liquid hydrocarbon mixture containing unsaturated compounds, which is characterized by extrusion from an ion exchange resin.

By the way, in the method of the original invention, the present invention desorbs a cation exchanger resin loaded with an unsaturated compound to be optionally washed and separated using a mononuclear aromatic hydrocarbon at a temperature of 50 to 150 qo and under standard pressure. It meets the additional requirements of Article 31, Item 1 of the Patent Act over the original invention in that it is carried out by passing the patent.

Claims (1)

[Scope of Claims] 1. Unsaturated compounds are removed from a liquid paraffinic hydrocarbon mixture whose components have only slight physicochemical differences by a macroporous dehydrated cation exchanger resin in the form of silver or copper salts. cations which are loaded with unsaturated compounds, optionally washed and separated, in a process where the unsaturated compounds are actually separated in large quantities by processing and producing a hydrocarbon product in which the unsaturated compounds are practically completely liberated. Desorption of the exchanger resin is carried out at a temperature of 50 to 15
1. A method for separating unsaturated compounds from a liquid paraffinic hydrocarbon mixture, which is carried out by passing a mononuclear aromatic hydrocarbon under standard pressure at 0°C. 2. The method according to claim 1, wherein the desorption is carried out with benzol, toluol and/or xylol. 3. A major amount of the desorbent is removed from the cation exchanger resin by passing nitrogen or other inert gas and used to separate the unsaturated compounds from a fresh hydrocarbon mixture and its 3. A process according to claim 1, wherein the desorbent is liberated by wiping the purified hydrocarbon product obtained. 4. The method according to any one of claims 1 to 3, wherein the cation exchange resin used to separate the unsaturated compound is washed with a non-polar unsaturated hydrocarbon before the adsorption treatment. . 5. The method according to any one of claims 1 to 4, wherein a paraffinic hydrocarbon mixture or an n-paraffin mixture that has been purified in advance by a conventional refining method is used as the raw material for the hydrocarbon mixture.