US3444261A

US3444261A - Process for the production of olefins suitable for conversion to detergent alkylates

Info

Publication number: US3444261A
Application number: US497513A
Authority: US
Inventors: Gianguido Caprioli; Serenella Pistoia; Emilio Pavan
Original assignee: Montedison SpA
Current assignee: Montedison SpA
Priority date: 1964-10-20
Filing date: 1965-10-18
Publication date: 1969-05-13
Anticipated expiration: 1986-05-13
Also published as: BE671088A; NL6513234A; FR1450245A; SE324357B; GB1110940A; ES319033A1; DE1493111A1

Description

United States Patent 3,444,261 PROCESS FOR THE PRODUCTION OF OLEFINS SUITABLE FOR CONVERSION TO DETERGENT ALKYLATES Gianguido Caprioli and Serenella Pistoia, Mantova, Italy, and Emilio Pavan, deceased, late of Mantova, Italy, by Serenella Pistoia, legal representative, Mantova, Italy, assignors to Montecatini Edison, S.p.A., Milan, Italy No Drawing. Filed Oct. 18, 1965, Ser. No. 497,513 Claims priority, application Italy, Oct. 20, 1964, 22,647/ 64 Int. Cl. C07c 3/30; C07b 21/00 U.S. Cl. 260683 2 Claims ABSTRACT OF THE DISCLOSURE In a process for the production of olefins suitable for conversion to detergent alkylates via the cracking of heavy petroleum fractions, the fractional distillation of the fraction thus-cracked and the separation therefrom of a fraction rich in straight-chain olefins, the improvement which comprises the cracking of a heavy petroleum fraction boiling within the range of from about 300 C. to 600 C. and containing more than about 35% by weight aromatics and less than about by weight straight-chain hydrocarbons, the separation therefrom of a second fraction rich in straight-chain olefins having from 8 to 15 carbon atoms and having a distillation range of from about 120 C. to 300 C., and the recovery of such straight-chain olefins having from 8 to 15 carbon atoms from said second fraction by treating the same with urea to selectively form adducts of urea with said olefins, separating these adducts and thence decomposing the same.

The present invention relates to a process for the preparation of alkylated aromatic hydrocarbons and, more particularly, to alkylbenzenes suitable for the production of detergents susceptible to biological degradation.

It is known in the art that the preparation of synthetic detergents from alkylaromatic hydrocarbons, using branched chain olefins for the alkylation of the aromatic hydrocarbons, gives rise to intermediate products for the preparation of detergents having excellent surface-active characteristics albeit undesirable compounds are also formed inasmuch as they are not biologically degradable or are biodegraded only after long periods of time.

Consequently, various methods have been developed for preparing olefin mixtures with a linear chain suitable for use in the alkylation of aromatic hydrocarbons so as to obtain alkylaromatic hydrocarbons perfectly suited for the preparation of synthetic detergents which are totally biodegradable within a set period of time.

In the light of such methods, olefins suited for the preparation of alkylated biodegradable detergents are obtained via the cracking (pyrolysis) of hydrocarbon mixtures, such as parafiinic waxes having special chemical and physical properties, or by cracking gas oil containing aromatic and naphthenic hydrocarbons at lower levels.

Such a procedure, however, is quite expensive because of the high cost of the hydrocarbon mixture to be subjected to cracking, or in relation to the particular purification operations of the high-boiling hydrocarbon mixtures which, in themselves inexpensive, do, however, effect olefins in such quantities and quality as to satisfy the necessary properties only if purified by very burdensome processes.

Accordingly, it is an object of this invention, to provide a process for the preparation of alkylaromatic hydrocarbons suitable for the production of biodegradable detergents, and according to which process the linear olefins necessary for the alkylation are obtained from heavy fractions of petroleum of any composition and containing any level of aromatic and naphthenic hydrocarbons.

These and other objects are achieved according to this invention, which consists of a process for the preparation of alkylaromatic hydrocarbons suitable for the production of biodegradable detergents by using as starting materials (raw material) heavy fractions of petroleum of any composition with a boiling point range of from 300- 600 C. such as gasoil, fuel oil and so on, submitting said heavy fractions to cracking under such conditions as to bring the content of long-chain monoolefins in the resulting hydrocarbon mixture to a maximum, separating by fractional distillation from said mixture a fraction comprising, inter alia, linear olefins having from 8 to 15 carbon atoms, subsequently treating this fraction with urea in a solvent for urea and, ultimately, in the presence of a diluent for the hydrocarbons, in such manner that the urea selectively forms an adduct with the linear chain olefins, subsequently decomposing said adduct in the presence of an aromatic hydrocarbon while maintaining the linear olefins in solution after separation of the urea by precipitation, and, after having previously added conventional Friedel-Crafts catalysts, directly effecting the alkylation reaction between said aromatic hydrocarbon and the linear chain olefins which are kept in solution.

According to the process of the present invention, alkylaromatic hydrocarbons are obtained in very high yields and are suitable for the production of biodegradable detergents starting from petroleum fractions of compositions that, from an economic point of view, discourage their use according to the methods employed so far, that is, for example petroleum fractions that, because of a very low content of linear hydrocarbons, even lower than 15% by weight, and a very high content of aromatic compounds, even higher than 35% by weight, would not profitably be used for this purpose.

The alkylaromatic hydrocarbons obtained according to the process of this invention lead, through sulfonation with oleum or S0 and subsequent neutralization, to alkylated detergents which are totally biodegradable within a set period of time and which, additionally, display superior characteristics in regards detergency and product quality.

More particularly, this invention relates to a process for the preparation of alkylaromatic hydrocarbons suitable for preparing detergents which are biodegradable, and which process characterizes itself by the following steps:

(21) Steam cracking a fraction of petroleum at a distillation temperature within the range of from 300 to 600 C., preferably between 350 and 550, this petroleum fraction being obtained via vacuum distillation of the residue of the atmospheric distillation of the crude oil pp These fractions of petroleum may be of any origin and may have any composition; for example, content of aromatic hydrocarbons may even be higher than 30%- 35% by weight, and the total content: of non-linear hydrocarbons (for example aromatics+naphthenes+isoparafiins) may be higher than by weight. The cracking conditions are chosen in such a way as to maximize the content of the linear mono-olefins.

The preferred conditions for the steam cracking comprise a temperature ranging from 550 to 650 C., a pressure of between 1 and 5 atm., a weight ratio between the load of hydrocarbons and the fed steam varying between 8 and 12, and a feeding velocity defined as space velocity (that is the quantity (expressed in kg.) of load+vapour which in a unity of time (1 hr.) flows through a volume unit of the cracking coil (expressed in 1.)) comprised between 1.0 and 7.0.

Upon cracking these fractions a hydrocarbon mixture is obtained which contains linear and branched chain cyclic monoand polyolefins and aromatics with contents thereof varying according ot the cracking conditions and to the composition of the starting mixture.

(b) The mixture emanating from the cracking is subjected to fractional distillation to obtain a fraction with a distillation range of from 120 to 300 C., comprising, inter alia, olefinic hydrocarbons of from 8l5 carbon atoms, preferably a fraction with a distillation temperature range of from 160260 C., and comprising the olefinic hydrocarbons of C -C (c) This fraction is then subjected to an extraction treatment with urea by means of which the linear hydrocarbons (mainly the normal olefins) are separated from the rest of the mixture, subsequent to the formation of an adduct with the urea.

The extraction with urea consists in extracting the hydrocarbon fraction, which fraction was separated from the mixture coming from the cracking, with a quantity of urea equal to 33.5- parts by weight of urea for one part by weight of product that may be transformed into an adduct, using a solvent for urea, preferably alcoholic such as, for example, methanol, and in a quantity equal to 0.51.2 parts by weight of alcohol per one part by weight urea.

Furthermore, when the quantity of linear hydrocarbons to be extracted by urea exceeds -30% by weight of the total weight of the hydrocarbon fraction to be treated, it is convenient to add a diluent for the hydrocarbons suflicient for restoring the percentage of linear hydrocarbons to the indicated values.

As diluents there may be used those substances that are miscible with hydrocarbons, that do not form adducts with urea and that do not decompose the adduct formed by the linear hydrocarbons, for example, branched, chlorinated, aromatic hydrocarbons and the like.

The extraction with urea is carried out in a mixer or other similar equipment that afiords intimate contact between the two phases that are formed: the solid phase, formed by the urea n-olefine adduct and the unreacted urea, and the liquid phases formed by all the rest, that is by the remaining non-linear hydrocarbons, saturated as well as unsaturated, cyclic and aromatic, together with solvent for the urea.

The reaction to form the urea n-olefine adducts is carried out at temperatures generally between from about 0 and 35 C. Good results are obtained when operating at temperatures between about 0 and C. at contact times varying from about 20 to 60 minutes depending upon the degree of stirring.

By effecting the extraction of the linear olefins with urea subsequent to the cracking, as has just been described another great advantage is achieved, which advantage represents a peculiarity of the process according to this invention. As a matter of fact, by operating in such a manner, a considerable portion of the heavy isoparaflins present in the charge at the cracking stage is transformed into linear long-chain olefins, however, by carrying out the extraction of the linear hydrocarbons before cracking, the isoparafiins would be for the most part eliminated from the charge and thus would be lost for all intents and purposes herein.

According to the process of this invention, said isoparafiins being transformed into linear olefins and subsequently extracted with urea, same can be used with a view to the economy of the process by contributing to the increase of the final yield.

The product of the urea n-olefin reaction is purified through suitable washings and filterings and is then de composed in the presence of a suitable solvent for the olefins by heating at a temperature of from 5080 C., with stirring, for a period of time generally around minutes. Many substances may be used as solvents for the olefins; particularly suited for this purpose are the 4 aromatic hydrocarbons such as benzene because, such being the case, there can be directly obtained the mixture of n-olefins dissolved in the aromatic hydrocarbons, which, in the presence of the Friedel-Crafts catalyst, directly yield the alkylaromatic hydrocarbons.

Upon decomposition of the adduct there is obtained n-olefins dissolved in solvent and, on the other hand, urea which can be reused for forming the adduct with other linear olefins.

(d) The mixture of linear olefins also comprising the aromatic hydrocarbon used as a solvent for the olefins in the decomposition of the adduct, is fed into the alkylation apparatus, into which there is also introduced an alkylation catalyst of the Friedel-Crafts type, such as, for example, AlCl .I-ICl, BF .HF or HF. Of course, the quantity of aromatic hydrocarbon must be equal (if it is the case by a subsequent addition) to the quantity required by the alkylation reaction, i.e., the molar ratio of aromatic hydrocarbon to olefin may vary from between about 4:1 to 8:1.

There occurs in the alkylation apparatus the formation of a mixture of alkylated aromatic hydrocarbons in which the length of the alkyl chain varies depending on the composition of the mixture of linear olefins used as the alkylating agent.

By operating according to the process of this invention, mono or dialkyl substituted aromatic hydrocarbons are obtained wherein over of the products have a linear chain.

(e) The fraction of monoalkylates, separated by fractional distillation from the alkylation mixture and from which has already been recovered excess aromatic hydrocarbon, is subjected to sulfonation with S0 or with oleum under conditions Well known to those skilled in the art.

The sulfonic acid thus produced is then neutralized With sodium or potassium hydrate, ammonium hydrate, amines, amino-alcohols, etc., so as to effect a paste or a liquid to which can be directly added additives and other constituents necessary for the formulation of commercial detergents.

The detergent formulations, both in powder form or as a liquid, which are prepared by taking as a base the alkylaryl-sulfonates obtained according to the process of this invention may contain additives that are normally incorporated in conventional commercial products, for example, they may contain other compounds of superficial activity, tripolyphosphates, optical bleaching agents, hydrotropies, foam-promoters, foam-inhibitors, foam-stabilizers, parfumes, corrosion-inhibitors and so on.

For example, a typical formulation may consist of the following components:

The active substance is formed from a mixture of alkaline alkylbenzenesulfonates differing from each other in the lengths of the linear chains attached to the benzene rings.

In order to determine the degree of biodegradability of the detergents produced according to the process of this invention, the test selected was that prescribed by German law. (Degree of the Biodegradability of detergents in washing or cleaning products, of Dec. 1, 1962, published in the Official Gazette of the German Federal Republic, part I, No. 49 of Dec. 12, 1962, page 698.)

As is generally known, the official rules relating to the testing prescribed by the aforesaid German decree on biodegradability are very strict, and, thus, they oifer with greatest safety the best proof of the excellent characteristics of biodegradability of the detergents prepared according to the process of this invention.

The results obtained from these tests demonstrate that the detergents obtained with the process of this invention have actually a biodegradability greater than 90%.

For even greater safety the biodegradability test was carried out with the same method on the active substance (mixture of monoalkylarylsulfonates) without all the components present in the formulation. Again the biodegradability turned out to be greater than 90%.

For determining the biodegradability, the active substance was subjected to the so-called River Water Test vis-a-vis the usual commercial products and again the detergents obtained displayed excellent biodegradability.

The River Water Test is a control method proposed by the British Institute, Committee on Methods for the Analysis of Trade Efiiuents (see The Analyst, volume 82, page 826, 1957).

This method consists in preparing a solution of detergent of very low concentration (around parts by weight per million) in river water in which the absence of anionic detergent has been previously ascertained, and in determining the residual concentration of non-degraded detergent at certain set intervals of time.

The invention will be further illustrated by the examples following hereinunder, which are merely intended to be illustrative and in no way limitative.

The examples are characterized by four processes that ditfer from each other by whether or not they include the phase of separation of the hydrocarbons with a linear chain: by the type of separation chosen, as an example, i.e., separation by solvent or by urea; at which point of procedure this latter type of separation is carried out, i.e., whether the separation by urea is carried out before or after the steam-cracking phase. In the various processes, the operations follow the order indicated in the following scheme:

(I) (No separation) steam crackingeAlkylation (2) Separation by solventsteam cracking- Alkylation (3) Separation by urea-a steam cracking- Alkalation (4)Steam cracking separation by urea- Alkylation The first three processes are given for purposes of comparison.

In all cases, the biodegradability test is eifected on the end product, and from the examples that follow, it will be seen that in order to obtain arylalkylic detergents having a maximum biodegradability, and starting from products of little commercial worth, i.e. with a low content of linear hydrocarbons, the best process will consist in effecting the separation by urea in the phase immediately following cracking.

The results of the tests illustrated by the examples and the numerical data relative thereto are all recorded in Table 1.

In all examples, the quantities are expressed in parts by weight, except where otherwise indicated.

Example 1 A definite quantity of heavy gasoil obtained by vacuum distillation of the residue of a topping of Libian crude oil and which had the following characteristics:

Distillation range C 350-550 Refraction index N 1.4848 Composition:

n-Parafiins per-cent 13.6 Isoparaffins and cycloparafiins do 4 6.7 Aromatics do 39.7

was subjected to steam-cracking under the following conditions:

Temperature C 610 Pressure Mg 1 Weight-ratio as feed charge/vapor 11.1

Space velooity=4.0 kg.

Total olefins: Percent n-Olefins 27 Other olefins 35.1

Aromatics 34.9

Parafiins 3.0

The yield in normal olefins with respect to the initial charge subjected to cracking was 1.97%

Then 100 parts of the fraction C -C were treated in an autoclave provided with a stirrer and a cooling jacket, and with a quantity of benzene corresponding to a molar-ratio benzene/ C C fraction=6 (the molar ratio, in this and following examples, refers to the average molecular weight of C -C fraction) and with anhydrous AlCl in the proportion of 5.4 parts by weight AlCl to 100 parts of the C C fraction. A current of dry HCl flowed until saturation was reached and the temperature was maintained at 34 C. for 70 minutes. The reaction mixture stratified into two liquid phases which were diflicult to separate, the lighter one being formed of excess benzene and of monoand polyalkylbenzenes, this latter phase, after decantation, washing with an equal volume of water, neutralization with 5% NaOH and subsequent fractioning separated a fraction having a distillation range of from 2703 60 C., and containing the monoalkylbenzenes.

From 100 parts by weight of the fraction C -C used for the alkylation, 12.1 parts of monoalkylate were obtained. This meant that from 100 parts by weight of initial charge subjected to cracking about 0.88 part of monoalkylate (100 ().073 0.121=0.88) were obtained.

An accurate analysis by infrared spectrography determined that the content of alkylbenzenes having linear chain was 32.0% so that the yield of linear monoalkylbenzenes with respect to the starting charge of gasoil was equal to 0.28% (100x 0.073 0.21 0.32:0.28).

100 parts of the fraction containing the monoalkylbenzenes were introduced into a reactor provided with a very efiicient stirrer (for example, a turbine) and fitted with a suitable cooling system.

To the hydrocarbon, while kept under heavy stirring, were added 108 parts of 104% oleum at such a rate that the temperature inside the reactor did not exceed 30 C. The time required for completing this addition was about 40 minutes.

Upon completion of the addition of oleum, the temperature was brought to 40 C. and stirring was continued for about minutes.

After this time had elapsed, 17.6 parts of water were added at such a rate that the temperature did not exceed 50 C.; generally this took from about 25 to 30 minutes.

Thereupon the stirring was stopped, the mass was transferred into a decanter and left to rest for about 8 hours, bringing the temperature to 20-22 C. In the decanter separation into the two phases took place: the upper one consisting of alkylbenzenesulfonic acid, the lower one consisting of slaked sulfuric acid.

The lower phase was then removed and the upper phase conveyed to a reactor fitted with a slow blade stirrer. Into the same reactor was then introduced a solution of 20% NaOH at such a rate that the temperature did not exceed 50 C. and in such a quantity as would be sufiicient to bring the pH of the slurry to about 7 and 9, and preferably between about 7.8 and 9.2.

Generally, about 129-139 kg. of monoalkylbenzenes were needed. The paste obtained had the following average composition:

Percent Active substance 45-49 Non-sulfonated 0.7-1.3 NaSO 5.0-10.0 H O 45-49 The slurry obtained was then dried, powdered and there was added thereto certain additives, so as to obtain a product having the following percentage composition:

, Percent Active substance (sodium alkylbenzenesulfonate) 25 Sodium sulfate 28 Tripolyphosphate 40 Sodium silicate 5 Carboxymethylcellulose 2 The thus formulated product was then subjected to the German biodegradability test as hereinbefore described. The biodegradability of the detergent, calculated according to this method was less than 50% and, thus, the detergent had to be defined as nonbiodegradable. The same test was repeated on the non-formulated product consisting merely of sodium alkylbenzenesulfonate, and in this case, also the biodegradability turned out to be lower than 50%.

The product obtained by the method of this example was also subjected to the River Water Test, the process corresponding to this test is described separately and is common to all the examples given.

Also according to the River Water Test, the product displayed unacceptable biodegradability. The results of this latter test are recorded directly in Table 2.

The numerical data corresponding to the entire process described in this example are recorded in Table 1, Column 1.

Example 2 Percent n-Parafiin 31.2 Isoparafiin and cycloparaffin 50.4 Aromatics 18.4

The wax thus obtained was subjected to steam-crackin g under the following conditions:

T (temperature) C 610 P (pressure) atg 1.0 Weight ratio of feed charge/ steam 11.0

Space velocity:

kg. (feed charge+steam)/hr.

litres of coil (as defined in Example 1) The outflow was cooled and fractioned in conventional manner. A fraction with a distillation range of from 8 170-250 C. was taken which comprises the C -C olefins.

From parts by weight of wax subjected to cracking, 9.50 parts of said fraction were obtained. The C -C (-250 C.) had the following composition:

Total olefins: Percent n-Olefins 61.2 Other olefins 21.8 Aromatics 14.5

Parafiins 2.5

The yield in n-olefins with respect to the quantity of starting gas oil that had been deoleated with dichloroethane, amounted to 1.11% (100 0.191 0.095 0.612=1.11).

The C -C fraction was then subjected to alkylation with benzene in the same way as described in Example 1, and by using a quantity of benzene with a molar ratio benzene/C C fraction equal to 6.1, a quantity of anhydrous AlCl in amounts of 3.6 parts by weight of AlCl per 100 parts of C -C fraction, and the other values (temperature, time, etc.) remaining unchanged.

After separation and fractioning a fraction was obtained having a distillation range of from between about 270-360 C. and containing monoalkylbenzenes in amounts of 83.2 parts by weight of monoalkylbenzenes per 100 parts of the C -C fraction used in the alkylation.

This meant that from 100 parts by weight of the starting gas oil there was obtained 1.50 parts of monoalkylbenzenes (100 0.191 0.095 0.832=1.50).

An accurate analysis through infrared spectrography test established that the content of alkylbenzenes having linear chains amounted to only 68.5% of the product obtained.

That is, from 100 parts by weight of the starting gas oil there was obtained 1.03 parts monoalkylzenzene with linear chains (1.50 0.685=1.03).

The product, sulfonated and formulated under similar conditions as those described in Example 1, displayed a biodegradability of lower than 50% as determined according to the aforesaid German test.

Similar to that described in the preceding example the same test was carried out on the non-formulated alkylbenzenesulfonate and a negative result was also obtained.

Also and according to the second River Water Test, the product like-wise exhibited insufficient biodegradability; the results of this latter test are directly recorded in Table II. V

The numeral data for process described in this example are recorded in Table 1, Column 2.

Example 3 A definite quantity of heavy gas oil obtained from the vacuum distillation of the topping residue from Lybian crude oil and having the following characteristics:

Distillation range C 440-580 Refraction index N 1.4820 Composition:

n-parafiins percent 14.7 isoparaflins and cycloparaffins do 54.4 Aromatics d0 31.9

was treated to precipitate the wax therefrom by means of a polar solvent (methylethylketone).

Thereby a quantity of wax was obtained equal to a 22.2% by weight with respect to the quantity of gas oil.

The composition of the wax was as follows:

Percent n-Paraffins 33.8 Isoparafiins and cycloparaffins 58.5 Aromatics 7.7

The =wax thus obtained was subjected to steam-cracking under the following conditions:

Temperature C 610 Pressure atg 1 Weight ratio feed charge/steam 11.0

Space velocity:

kg. (feed charge+steam)/hr. litres of coil (as defined in Example 1) The outflow was cooled and fractioned in conventional manner.

A fraction with a distillation temperature range from 170250 C. was taken, which was comprised of C -C olefins. From 100 parts by weight of wax subjected to cracking, there was obtained 10.70 parts of said fraction, while, with respect to 100 parts of starting gas oil, the quantity of said fraction amounted to 2.37 parts by weight (100 0.222 O.107 =2.37).

The C -C fraction (with a distillation range of from 170-250 C.) displayed the following composition:

Total olefins: Percent n-Olefins 68.6

Other olefins 20.9

Aromatics 4.0

Paraffins 6.5

The quantity of n-olefins obtained from 100 parts by weight of starting gas oil amounted to 1.62 parts byweight (100x0.222 0.107 0.686:1.62).

The C -C fraction (170250 C.) was subjected to alkylation with benzene in the same manner as described in Example 1, and by using a quantity of benzene equal to a molar ratio of benzene/C -C fraction equal to 6.1, a quantity of anhydrous AlCl equal to 3.3 parts by weight of A1Cl for 100 parts of C C fraction used in the alkylation, and by maintaining the temperature at 33 C. for 60 minutes.

After separation and fractioning, a fraction was obtained having a distillation range of from 270-350 C. and containing monoalkylbenzenes at a rate of 93.4 parts by weight of monoalkylbenzenes for 100 parts of the C C fraction used in the alkylation.

An accurate analysis by means of an infrared test determined that the content of alkylbenzenes having linear chains was equal to 71.0% of the monoalkylate obtained.

On the whole, for 100 parts by weight of starting gas oil, 2.22 parts of monoalkylate (100 0.222 0.l07 O.934=2.22) and 1.57 parts of linear monoalkylate (2.22 O.71=1.57) were obtained.

The product, sulfonated and formulated under conditions similar to those described in Example 1, exhibited according to the aforesaid German test a biodegradability of less than 50%. This is an absolutely unacceptable biodegradability rate.

The same test was repeated on the non-formulated product, consisting merely of sodium alkylbenzenesulfonate, but in this case also the biodegradability was less than 50%.

The pure product i.e. the non-formulated alkylbenzenesulfonate was also subjected to the River Water Test. The process concerning this test is described separately since it is common to all the given examples and the results are recorded on Table 11.

Also according to the River Water Test the product displayed a biodegradability that was unacceptable. The results of this latter test are directly recorded in Table II.

The numerical data of the full process described in this example are recorded on Table 1, column 3.

Example 4 A certain quantity of heavy gas oil obtained from the vacuum distillation of the topping residue of a Lybian crude and having the following characteristics:

Distillation temperature range C 400-500 Refraction index N 1.4835 Composition:

n-Parafiins percent 13.7 Isoparafiins+cycloparaflins do 48.2 Aromatics do 38.1

was treated by partial melting, filtering and subsequent refining with methylethylketone.

A quantity of wax was obtained equal to 16% by weight with respect to the quantity of gas oil. The wax obtained displayed the following composition:

Space velocity:

kg. (feed charge+steam)/hr. 4.1

litres of 0011 (defined as in Example 1) The outflow, cooled and fractioned in conventional manner. A fraction was obtained with a distillation range of from l70250 C. and comprising the C -C olefins. From parts by weight of wax, 9.0 parts of said fraction were obtained, while, with respect to 100 parts by weight of the starting gas oil, the quantity of said fraction amounted to 1.44 parts (100 0.l6 0.09=1.44).

The C -C fraction -("-250) had the following composition:

Total olefins: Percent n-Olefins 71.5 Other olefins 22.3 Aromatics 3.0 Paraffins 3.2

The quantity of n-olefins obtained from 100 parts by weight of the starting gas oil was 1.03 parts (100 0.16 x0.09 0.715=1.03).

The C C fraction was subjected to alkylation with benzene by operating the same way as is described in Example 1 and by using a quantity of benzene with a molar ratio benzene/C C fraction=6.0, a quantity of anhydrous AlCl equal to 3.3 parts by weight of AlCl for 100 parts of the C -C fraction used in the alkylation, and by maintaining the temperature at 32 C. for 70 minutes.

After separation and fractioning, a fraction with a distillation range of from 270360 C. was obtained that contained C C monoalkylbenzenes at the rate of 97.0 parts by weight of monoalkylbenzenes for 100 parts of C -C fraction used in the alkylation.

The infrared spectrographic analysis revealed a content of alkylbenzenes having linear chains equal to 74% by weight of the total monoalkylbenzenes obtained. From 100 parts by Weight of gas oil one obtained therefore 1.40 parts of monoalkylate (100 0.16 0.09 0.97=1.40) of which 1.03 parts were monoalkylate having a linear chain (1.40 0.74=1.03).

The monoalkylate, sulfonated and formulated under the same conditions as those described in Example 1 displayed a biodegradability as determined according to the German test, of less than 50% The same test was carried out on the non-formulated product consisting solely of sodium alkylbenzenesulfonate 1 1 and in this case also the biodegradability was lower than 50%.

The pure product, i.e., the non-formulated alkylbenzenesulfonate, was also subjected to the River Water Test and according to this method, the result was also negative. The results of the River Water Test are directly recorded in Table II.

The numerical data of the full process described in this example are recorded in Table 1, Column 4.

Example A certain quantity of heavy gas oil, having the same characteristics at the gas oil used in Example 1, was treated with urea to isolate the n-paraffins according to the following procedure:

Into a mixer or other vessel fitted with a very efficient stirrer were introduced 130 litres of H 0 and the temperature was brought to 40 C. Then, under vigorous stirring, 350 kg. of urea and 160 kg. of methylisobutylketone were added. Upon completion of this addition, still under stirring, 100 kg. of heavy gas oil were introduced into the mixer and the temperature was gradually brought down to 22 20 C. in 30 minutes.

Thereupon the adduct thus formed was separated by filtration from the urea solution and the methylisobutylketone.

The crystals of the adduct were then mushed into about an equal quantity by weight of methylisobutylketoue, filtered again, and then dried in order to completely eliminate the solvent.

The adduct was then decomposed with water at a temperature of from about 6080 C.

The oily phase, consisting for the most part of the parafiins which had formed the adduct with the urea, was then separated from the urea solution (which may be recycled) weighed 18 kg. and had the following composition:

Percent n-Paraflins 71.0 Isoparafiins-l-cycloparafiins 25.1 Aromatics 3.9

The wax thus obtained was subjected to steam cracking under the following conditions:

Temperature C 610 Pressure atg 1 Weight ratio of feed charge/stem 110 Space velocity= kg. (feed charge+steam)/h.

litres of coil (defined as in Example 1) Total olefins: Percent n-Olefins 83.7 Other olefins 12.3 Aromatic 1.70 Parafiins 2.3

The quantity of n-olefins obtained from 100 parts by weight of starting gas oil amounted to 1.49

Said fraction was then subjected to alkylation with benzene following the same procedure as described in Example 1 under the following conditions:

Molar ratio benzene/C -C fraction 6.0 Temperature C 33 Time minutes 35 Quantity by weight of anhydrous AlCl for 100 parts of c10C14 fraction 2.8

After separation and fractioning was obtained having a distillation temperature range between 270 and 360 C. and containing C -C monoalkylbenzenes at the rate of 100.0 parts by weight of monoalkylbenzenes for 100 parts of the C C fraction used in the alkylation.

An accurate infrared spectroscopic analysis determined the content of linear chain alkylbenzenes to be of the monoalkylate obtained.

On the whole, for parts by weight of starting gas oil, 1.78 parts of monoalkylate and 1.51 parts (1.8 0.85) of monoalkylate containing linear chain alkylbenzenes were obtained.

The product, after sulfonation and formulation under the same conditions as those described in Example 1, showed a biodegradability equal to 78% as determined according to the aforesaid German test.

Similarly to that described in Example 1, the same test was also carried out on non-formulated alkylbenzenesulfonate, and there was also obtained an unsatisfactory result.

The pure product, i.e. the non-formulated alkylbenzenesulfonate was also subjected to the River Water Test. The results of this method were not altogether satisfactory. The results of the River Water Test are directly recorded in Table II.

The numerical data of the entire process described in this example are recorded in Table 1, column 5.

Example 6 A certain quantity of heavy gas oil, having the same characteristics as the gas oil used in Example 1, was subjected to steam-cracking under the following conditions:

Temperature C 610 Pressure atg 1 Weight ratio feed charge/steam 11.1

Space veloeity= kg. (feed charge +steam) /l1. litres of coil (defined as in Example 1) The outflow was then cooled and fractioned in conventional manner and a fraction with a distillation range of from 250 C. and comprising the C -C olefines was separated therefrom.

From 100 parts by weight of gas oil there were obtained 7.30 parts of the above fraction. The C -C fraction (170250), displayed the following composition:

Total olefins: Percent n-Olefins 27.0 Other olefins 35.1 Aromatics 34.9 Paraflins 3.0

The yield in n-olefins with respect to the starting charge subjected to steam-cracking amounted to 1.97%

to 180 C.; they were used with the purpose of promoting the mixing.

After 30 minutes the solid mass (adduct of the urea with n-olefins) comprising isoand cycloolefins and aromatics, was separated from the oily mass, and from the methanol through filtering (centrifugation). The methanol, containing 10 kg. of dissolved urea, was separated by decantation and could be utilized in other charges without further treatment. From the oil the methanol dissolved by distillation was recovered.

The adduct (143 kg.) was then suspended in 100 kg. of anhydrous benzene and then filtered or centrifuged. The recovered benzene could be used just as it was for the washing of the subsequent charges, or could be immediately purified by distillation. The solid filtrated mass was then suspended in 72 kg. of anhydrous benzene and brought to 65 C. for 30 minutes, under constant stirring and the adduct decomposed with quantitive separation of the urea. The urea (110 kg.) was then decanted and could be used without further manipulations in successive operations.

The determination of the yield of the extraction with urea and the quality of the n-olefins were determined using a small fraction of the liquid, from which the urea had been separated according to the following procedure: 100 g. of the mixture were subjected to fractional distillation until the benzene was wholly eliminated: the residue was weighed and analyzed by mass and by infrared spectrography. From 100 g. of C C fraction containing 2.7 parts by weight n-olefins there were obtained 25.8 parts by weight of olefins (residue) with a content of nolefins equal to 98.4% by weight.

In other words, the extraction yield based on the normal olefins contained in the C -C fraction was equal 110 The liquid, consisting of benzene containing dissolved olefins, and from which the urea had been separated, was brought to 33 C. and then subjected to alkylation in the same manner as that described in Example 1. The molar ratio benzene/C C purified fraction was equal to 6.0.

In this case, only 0.62 kg. of AlCl (i.e. only 2.4 parts with respect to 100 parts of purified C C fraction) were required to complete the reaction. The alkylation temperature was 33 C. for a period of 60 minutes.

The alkylated liquid was then decanted, washed and neutralized, and was then fractioned in the same way as that described in the preceding examples. A fraction was obtained having a distillation range of from 270360 C. and containing the monoalkylbenzenes.

From 25.8 parts by weight purified linear olefins subjected to alkylation there were obtained 26.5 parts of monoalkylbenzenes, i.e., a quantity equal to 103% by weight.

The yield of monoalkylbenzenes based on starting charge of heavy gas oil was equal to 1.93 parts by weight for 100 parts (10 0X0.073 0.258 1.03:1.93). Analysed by means of very accurate infrared spectrography, the above fraction revealed a content of linear alkylbenzenes equal to 98.6%, wherefore the yield in linear monoalkylbenzenes was the highest with respect to the preceeding examples and equals 1.90 by weight based on the starting charge of heavy gas oil (100X0.073 0.258X 1.03 X0.986:1.90)

The above mentioned fraction containing the monoalkylbenzenes was sulfonated, etc., and there was added thereto all the various additives according to the formulation used in Example 1.

The product thus prepared was then subjected to the biodegradability test according to the aforesaid German test and exhibited an actual biodegradability of 97%.

The same test was repeated on the non-formulated product, consisting solely of sodium alkylbenzenesulfonate.

In this case also the biodegradability was very high.

Also, according to the River Water Test, the product exhibited excellent biodegradability, the results of this latter test being directly recorded in Table II.

The numerical data of the complete process described in this example are recorded in Table 1, Column 6.

Example 7 In a preferred form of execution, a fraction of gas oil of high boiling point, having a distillation range of from 350-550 C. and having the same characteristics of the gas oil used in Example No. 1, was subjected to steam cracking under the following conditions:

Temp. C 640 Pressure atm 1.0 Weight ratio feed charge/steam 10.8

Space velocity=4.9 kg. (feed charge+steam)/hr.

litres of coil (defined as in Example 1) The outflow was cooled and fractioned in conventional manner and there was obtained therefrom a fraction having a distillation range of from 170-250 C. and containing the C -C olefins.

From 100 parts by weight of gas oil there were obtained The yield in n-olefins based on the charge was 2.54% (100 0.089 0.285=2.54).

100 kg. of the fraction containing the C -C olefins were treated with urea in similar manner as described in Example 6, but using 125 kg. of urea and litres of a methanol/ hydrocarbons mixture consisting of 104 litres of methanol and of 6 litres of hydrocarbons (these hydrocarbons consisted of a mixture of residual oils from preceeding extraction of the n-olefins). One preceeded as in Example 6 until the adduct was decomposed and the urea was separated, the yield of the extraction with urea was then determined, as well as the quality of the extracted olefins, still according to the method described in Example 6.

From 100 parts by weight of C -C fraction containing 28.5 parts of n-olefins, 27.15 parts of olefins (residue) were obtained, which after analysis by mass and infrared spectrometry, revealed a contents of n-olefins equal to 97.6% by weight.

The extraction yield based on the olefins contained in the C -C fraction was 93.0%

15 16 the molar ratio benzene/C C purified fraction was EXPLANATORY LEGEND CONCERNING TABLE 1 equal to 6.1. Also, in this case only 0.62 kg. of AlCl Charge (1) (that is, only 2.4 parts based on 100 parts of purified @zDi mam rangec. C -C fraction) were eventually necessary for complet- (3)=N n-Paraffin percentage in the charge (1).

. (4) mg the reaction. The alkylation temperature was 32 C- (5)=Is +cycloparafl1n percentage in the charge (1).

fo a riod of 60 i t s. (6) =Ar0n1atic percentage in the charge (1). Thereupon, the alkylated liquid was decanted, washed Type or purification and neutralized, and then fractioned in the same manner p c of the charge d d h l (8) =n-Paraifins percentage 111 that extracted. as 65cm 6 In t e Prece g eXamP (9)=lso+cycl oparaflins percentage in that extracted.

From 100 parts by welght of purified llnear olefins 10 Percentage In that extmetedthere were obtained 100.2 parts of monoalkylbenzenes Steam-cracking (isolated fraction having a distillation range of from 270- lglt ierlslerrit ge 0.). 360 C.) with a yield, based on the starting heavy gas oil %f charge of 2.42% (100 X 0.089 X 0.2715 1.002=2.42) (14) char56611190111- that is, about 25% more than that of Example 6, and 15 010- 14 Fr n (d st llat range 0 3 5% more h that f Example 5 (15 =Yield in respect of the charge under cracking.

(lb) =Y1eld in respect of the charge (1). An accurate analysis by infrared spectography revealed (17)=Perce11tage 01mm] olefins in the 010-014 fraction. a content of monoalkylbenzenes having linear chains of 83512352335: gg gg gg I 10 14 98.5%, thus bringing the yield of monoalkylbenzenes of 20 =Pe en ta fparaffins in he 0 0 fraction, linear chain to 2.38 parts in a hundred based on the start- 20 (21)=Quantlty "91mm Obtamed {mm 100 Parts charge ing gas Oil. Type of purification The f i containing h monoalkylbenzenes was flgggoTlTotal extracted hydrocarbons in respect of 100 parts of 0 0-01 then sulfonated, 6116., and there was added thereto the (23) =1crcentage of n-olefins in the extracted hydrocarbons. various additives according to the formultaion used in EX- 311 36213211iifii rii xii liiolf per 100 parts of olefins contained ample 1. The product thus prepared was subjected to 25 (25)=11-Olefin5 extracted per 100 parts of charge (1). the b1odegradabil1ty test according to the aforesaid Ger- Alkylation man test and revealed a blodegradability of 96.4%. (2(5)=C C fraction (parts by wei ht) fed to alkylation.

The same test was repeated on the non-formulated g ggggggf gg g g g product, consisting merely of sodium alkylbenzene sul- (29)=Tlme (minutes). f 3O (30) =Quantity 01' A1011 in respect of 100 parts of Clo-C14 traction. I this case lso the biodegrad bilit w r hi h Monoalkylbcnzene obtained (distillation range 2703fi0 C.)

(31) =Quantity of monoalkylate obtained (parts by weight). Also accordmg to Rlver er Test the prodmft (32)=Qua\1tity of monoalkylate obtained (parts by weight) per 100 displayed an excellent biodegradabihty. The results of this parts of 010-01. fraction fed to the alkylation. latter test being recorded in Table IL plegiggglngtgtafi monoalkylate obtained (parts by weight) per 100 The numerical data of the entire process as described 35 (34)=Qua.11tity 0! linear monoalkylate obtained (parts by weight) in this example are recorded in Table I, column 7. Per 1001mm change TABLE I Example No 1 2 3 4 5 6 7 Feed charge (1):

Solvent Solvent Solvent Urea 610 610 610 1 1 1 4. 1 4. 3 4. 1 (14) 11. 0 11. 0 11. 0 Fraction Gm-C14 (distillation range 170- 250 0.):

Urea Urea tained (distillation range 270360 0.):

1 Not biodegradable.

17 CONTROL OF THE BIODEGRADABILITY AC- CORDING TO THE METHOD OF THE RIVER WATER TEST All the products obtained according to the methods described in Examples 1 to 7 were subjected, as mentioned in the examples themselves, to the River Water 18 sponding to the different analyses are recorded in Table II.

From the examination of the values obtained it can be inferred that according to the River Water Test also the alkylbenzenesulfonate obtained according to the process of this invention (see columns corresponding to Examples 6 and 7) exhibits the greatest biodegradability.

TABLE II N a alkylbenzene sulionate Example irom tetra- Samples propylene 1 2 3 4 5 6 7 Initial cone. in p.p.m. 9. 8 9. 7 10. 2 10. 3 9. 9 10. 1 10. 3 10. 2 Residual cone. after (days) 9. 7 9. 8 10. 1 10.2 9. 9 10. 1 10.2 10. 3 2 9. 9 9. 7 10. 1 10. 3 10.0 10.0 9. 8 10. l 9. 8 9. 6 10.2 9. 5 9. 9 8.7 6. 3 5. 5 9. 6 9. 7 10.0 9. 6 9. 8 5. 5 2. 5 3. 1 9.4 6.1 9.8 9.6 9.4 5 0.5 0.3 9.4 4.9 9.4 5.6 8.6 4.8 0.4 0.3 9.3 4.8 6.3 5.4 8.2 4.2 0.3 0.4 9.0 4.6 6.1 5.2 8.0 3. 9 0.2 0.2 9.1 4.6 6.1 5.2 7.7 3.7 0.1 9.1 4.5 0.0 4. 9 7.6 3.7 9.0 4.6 5.9 4.8 7.5 3.5

Test in order to check the biodegradability according to this method.

The control procedure according to this method is common to all examples with respect to the quantity of the substances used and with respect to control times, wherefore it will be described hereinafter and will be valid for all examples.

The results obtained are recorded in Table II.

For this purpose, the pasty masses obtained through neutralization of the alkylbenzenesulfonic acids (obtained by sulfonation of the fraction of C -C monoalkylbenzenes) were accurately purified from the sodium sulfate and then dried. This process was carried out separately for each example.

The purified sodium alkylbenzenesulfonates corresponding to the seven examples were introduced separately to glass vessels containing river water in such quantity as to have an initial concentration equal to about 10 p.p.m.; the concentration was checked with methylene blue.

The glass vessels were locked and the solutions stored at room temperature.

In another vessel a comparative solution was prepared following the same procedure, i.e. a solution of commercial sodium alkylbenzenesulfonate obtained from tetrapropylene (10 p.p.m.) The eight solutions are analyzed periodically according to the methylene blue method. The concentration of the product corresponding to each example was compared with the concentration of the alkylbenzenesulfonate derived from tetrapropylene. The values As many apparently widely different embodiments of this invention may be made Without departing from the spirit and scope thereof, it is to be understood that the same is not to be limited to the specific embodiments thereof, except as claimed in the appended claims.

What is claimed is:

1. In a process for the production of olefins suitable for conversion to detergent alkylates via the cracking of heavy petroleum fractions, the fractional distillation of the fraction thus-cracked and the separation therefrom of a fraction rich in straight-chain olefins, the improvement which comprises the cracking of a heavy petroleum fraction boiling within the range of from about 300 C. to 600 C. and containing more than about 35% by weight aromatics and less than about 15% by weight straight-chain hydrocarbons, the separation therefrom of a second fraction rich in straight-chain olefins having from 8 to 15 carbon atoms and having a distillation range of from about 120 C. to 300 C., and the recovery of such straight-chain olefins having from 8 to 15 carbon atoms from said second fraction by treating the same with urea to selectively form adducts of urea with said olefins, separating these adducts and thence decomposing the same.

2. The process as defined by claim 1, wherein the selective formation of adducts of urea with olefins is efiected by treating the said second fraction with an alcoholic urea solution having from 3.5 to 5 parts by weight urea with respect to one part by Weight of straight-chain olefins and having 0.5 to 1.2 parts by weight alcohol with of the various concentrations and the time intervals correrespect to one part by weight urea.

References Cited UNITED STATES PATENTS 3,328,313 6/ 1967 Dellow 208--25 X 2,737,508 3/ 1956 Axe 20825 FOREIGN PATENTS 251,716 11/1960 Australia. 852,079 10/ 1960 Great Britain.

DELBERT E. GANTZ, Primary Examiner.

CURTIS R. DAVIS, Assistant Examiner.

US. Cl. X.R.