DE1593599A1 - Use of sulfuric acid in the alkylation - Google Patents

Description

4593599

PATENT LAWYERS

-Dr.-lna.::*:.'- '■' ■■ - ^Λ · ""' ¹ ^ Dipl.-I'"■ ·. ■ '· '"<"· ■ - '■ ^ ¹ '' ^{! l} ·

an 27, Pienzeiiiiuei ■? · * ·· i

Texaco Development Corporation, New York 17, New York, V.St.A.

Use of sulfuric acid in the alkylation

The invention "relates to improvements in the use of sulfuric acid made in applied to the alkylation of olefins or aromatics in the presence of a sulfuric acid catalyst is »More particularly, the invention relates to a method for restoring the catalytic Effectiveness of the sulfuric acid catalyst through absorption of the olefins contained in it, separation of the alkyl sulfates formed in this way from the impurities of the alkylation and alkylation

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of alkyl sulfates with release of 100 percent sulfuric acid * According to the invention, olefin feedstocks are used which are isobutylene in admixture with other olefins, these substances being treated with dilute sulfuric acid before they are brought into contact with strong sulfuric acid. According to one embodiment of the invention the sulfuric acid alkylation catalyst is brought into contact with olefin-forming alkyl sulfates, at least a portion of the alkyl sälfate is extracted and at least a portion of the remaining acid is brought into contact with other olefin-forming alkyl sulfates.

If strong sulfuric acid, such as fresh Alkylierungssäure for loading or as a catalyst used Alkylierungssäure with a titratable acidity of about 85-90 $> and with only about 2-4 i> water for the absorption of isobutylene-containing materials used in conditions for If propylene and n-butylene absorption are used, a substantial part of the isobutylene is subject to disadvantageous irreversible side reactions which result in a loss of isobutylene and also of acid

Propylene,

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Propylene, which is essentially free of butylenes or buttylenes free of isobutylene are required for obtaining good results in the acid recovery process.

The invention includes a combination of steps that act as a co-amine by which isobutylene, which contains foreign · components, can be used with excellent results · Isobutylene is obtained through a better process · The Process involves the absorption of isobutylene from a butylene feed in weak sulfuric acid Clay of insufficient strength for alkylation, extraction or exhaustion of the absorbed isobutylene with isobutane, absorption of the unabsorbed n-Butylenes by used alkylating acid, extraction clay dibutyl sulfate with isobutane, which result in the elimination of alkylation impurities has and alkylation of the recovered isobutylene and the dibutyl sulfates with isobutane · A special one The characteristic is that isobutylene and n-butylene are extracted or recovered as dibutyl sulfates from the reaction mixture of acid absorption with isobutane and turn the recovered olefin and the alkyl • ulfmte without separation τοη isobutane with alkylation can be inserted. It is not just the ISO009836 / 2128

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butylene is recovered and alkylated, but its removal from the n-butylenes enables that the n-butylenes are used as feed components for the absorber for acid recovery can be.

An object and advantage of the invention is that isobutylene containing feedstocks for the recovery of the used alkylating acid can be used and that thereby in large Hate the applicability of the acid recovery process is being extended · Another subject and The advantage of this process is that it can carry out a higher conversion of the sulfuric acid catalyst Dialkyl sulfates with subsequent high recovery of the sulfuric acid catalyst after their alkylation Propylene materials free of butylenes and devices for the separation of butylenes of propylene are not required according to the invention · Other advantages are that a higher yield of alkylated starting olefin and a lower one Net consumption of acid from the same feedstock will be obtained by the process Isobutylene is not only economically removed and recovered from the substances it contains, but it becomes economically usable through its alkylation

power.

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power. The alcohol, the polymers and the alkyl sulfates, which are formed during the absorption and recovery of the isobutylene can be obtained by extraction and alkylation use can be useful.

Having thus set forth the general nature of the invention, it will best turn out the more detailed description with the drawing can be understood »Although the drawing shows an arrangement the apparatus in which the process according to the invention can be carried out is it is not intended to limit the invention to the particular apparatus or materials described ο

According to the figure, a butylene feed gas containing isobutylene is passed through line 10 at a strength of 1056 g / cm and flows towards an absorber 11 for isobutylene near the bottom, sulfuric acid with a concentration of 50-70 weight percent Wasaer acid on a base is introduced via line 12, cooled to about 12.8 ⁰ C in cooler 13 and passed through line 14 to the top of the tower 11 · the main amount of the acid is weiterzirkulierende acid, and only a very small portion of the available

posed

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Provided acid is required. The acid provided can be fresh sulfuric acid, used alkylation catalyst or, preferably, raffinate spent acid from the acid of the recovery system as shown in line 15. The tower operates at a head temperature of about 24 ⁰ C and a steam discharge pressure of about 517 Torr, so that unabsorbed substances, including n-butylene, flow out of the tower through conduit Isobutylene reacts with the descending sulfuric acid.

The polymer formed in the absorber 11 is deposited as a liquid layer on the bottom of the absorber 11 and is decanted, drawn off through line 16 and fed to the engine fuel in a manner not shown here or passed to the alkylation zone through line 16. The polymer is preferably sent to the alkylation, because it contains dissolved Al lcylejg.1t ate and butyl alcohols

-., Jf. 1

can. The n-butylenes in line 18, which are essentially are free of isobutylene, are passed through the compressor 19 and cooler 20 and form one ! Liquid in line 21..

liquid

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Liquid olefin feed in line 21 is fed to the bottom of absorber 23. Additional olefin feed, which may consist of a propylene stream or other isobutylene-free olefin, can be introduced through line 23. Acid catalyst used for the alkylation of approximately 90% H ₂ SO. Concentration is passed through line 25 to the top of countercurrent absorber 22 · Absorber 22 works in the liquid phase at about 3102 torr, and a temperature of -7 to

will 4 »5 C / d" by protruding part of the outflow Liquid from the bottom of the * liquid separator 26 and line 27, cooler 28 and return of cold liquid to the absorber 22 through line 29 are maintained. The liquid in the upper part of the absorber, which contains some dissolved alkyl sulfates and the olefin which has not reacted, is withdrawn through line and passed to the alkylation zone 37.The reaction mixture obtained by absorption, which contains dialkyl sulfate, is passed through line 33 to the top of the Countercurrent extractor 34 is directed. Isobutane is led to line 35 to the bottom of extractor 34. The top layer, which contains isobutane and dibutyl sulfate and is essentially free from alkylation impurities, is passed through line 36

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passed to alkylation reactor 37 · The raffinate (raffinate) or the spent acid is drained from the bottom of the extractor 34 through line 38. The used acid contains alkylation impurities, such as acid-oil complex and water, and the unextracted alkyl sulfates.

■ Two absorbers and two extractors can advantageously be used, the Raffinate acid from the first extractor is used as the feed acid for the second absorber. By doing The first absorber can be the concentration of the acid made available to the absorber and the proportion of the absorbed olefin can be controlled so that organic impurities necessary for the alkylation harmful are not extracted in the extraction stage will. As another possibility, as it is shown, some of the raffinate acid can be added to the Absorbers duroh lines 15 and 40 returned again will.

According to a method for using the raffinate acid as the feed acid for the Absorber with dilute acid is a (Peil the acid from line 15 through line 4-1 sum YerdünnimgetaiLk 42 passed along with enough water or dilute acid introduced through line 43,

around

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ma. dun öätiregr & ü eis to 50 days 85 weight percent H ₂ SO, at termiiLdem. Veratinntes Baffin at is then through line 44 to extraction column 4? where it goes in countercurrent with isobutane, which passes through. Line 46 is introduced, comes into contact. Secondary olefin is sucked out of the dilute raffinate and the outflowing stream of isobutane and secondary olefin is withdrawn through line 47 as a feed material for the alkylation zone 37. Acid separated from column 45 is withdrawn through line 48 and with the acid in line 15 to the Absorption system with dilute acid

The acidic phase from absorber 11, which contains absorbed isobutylene, is passed through line slim extractor 51 for dilute acid »extractor 51 is a packed column which is used for liquid-liquid extractions. Isobutane is directed to the bottom of extractor 51 through line 52, heater 55 and line 54. The top layer from extractor 51, which contains isobutane, isobutylene, and acidic isobutyl sulfate, is passed through line 55 to alkylation reactor 37. The phase poor in acid becomes the isobutylene absorber 11 by conduction

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The isobutylene absorbed in the absorber 11, the n-butylene absorbed in the absorber 22 and additional isobutane from line 60 and olefin feed from line 61 are alkylated in the alkylation reactor 37 with a sulfuric acid catalyst. There are fresh sulfuric acid from 98.0 to 99 _f 5 #iger Concentration fed through line 62 and into line 63 recirculated acid of about 90 5 »sodium concentration also the Eeaktor 37 · The blend for the Alkylierungsreaktbix is passed through line 64 to the separator 65 The acid phase and hydrocarbon phase are separated in the separator 65, the acid phase is returned to the alkylation zone 37 through line 63 and the outflowing hydrocarbon is drawn off through line 66 to the usual fractionation and crew guiding device 67. In the device 67, the alkylated product is separated and fed through

70 drained as engine fuel or for other purposes. η-butane and propane are supplied through lines

71 and 72 respectively withdrawn, and isobutane is passed through line 73 for return to the line 60 and alkylation zone 37 withdrawn «

absorption

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Absorption, of isobutylene

Any feedstock that is isobutylene contains »can for reaction» it or for absorption can be used in dilute sulfuric acid, such as C.- £ ractions and C_-C. fractions of the catalytic Cracking, the absorber exhaust in catalytic Cracking and that which escapes during polymerizations Gas.

For the removal of isobutylene from an olefinic feed can have acidity of about & kr 45 to 70% concentration can be used, where a concentration is about 60-65 # advantageous is. A feature of this stage of the process is the extraction of essentially all of it Isobutylene, because the isobutylene remaining in the n-butylene otherwise would destroy an excess of the acid catalyst for the alkylation with the formation of bialkyl sulfate. Be like that selects the conditions so that rather the full Removal of isobutylene required «when a high degree of separation is achieved Conditions which promote the complete removal of isobutylene, are the use of acid of about 65 concentration, effective countercurrent contact

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Treatment and Use of Excess Dilute Acid * The alcohols and polymer produced are used essentially without any expense for a separation process because they occur in the feedstocks that are sent to the alkylation # Water and, according to nitration, contains 85% or higher H ₂ SO. Is too strong for good results · You kiss must be sufficiently diluted so as not to absorb a substantial proportion of the n-butylene or propylene Acid catalyst used alkylation can be used as the feed acid "provided it is diluted with reaction mixture containing the desired water" The dissolved isobutylene is more easily extracted or extracted from dilute acid "but because the cost of the extraction stage is relatively low in the process, e3 is more important essentially because isobutylene is added from the n-butylenes remove than to make the isobutylene easily extractable from the reaction mixture. The formation of sour? Isobut, - <Iensulfat is promoted by a higher acidity. A lower degree of acidity promotes the formation of tertiary butyl alcohol.

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The temperature for isobutylene to be absorbed is not critical and the operable temperature range will depend on a number of factors including the acid concentration. Lower concentration acids allow higher temperatures to be used and higher concentration acids require lower temperatures to be used for good results. A temperature of about 24 ⁰ C and the acid concentration of about 65 #iger is satisfactory, and it is in. generally a temperature below about 38 ^° C. is used. The temperature for absorption is advantageously close to or not because; below the extraction or separation temperature because dilute acid is recycled from the extraction stage to the absorption stage »

It is advantageous to carry out the absorption in the vapor phase, whereby the n-butylenes, which do not react can go out of the extraction vessel into the vapor phase. Sine liquid However, the absorption phase is satisfactory and, under some conditions, a more complete removal of isobutylene can be obtained in the liquid phase »Under the conditions described, very small amounts of polymer formed. If conditions

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are used for a liquid phase, vMrat isobutylene and the polymer or the acidic isobutyl sulfate, which is dissolved in the liquid butylene phase, advantageously removed before addition to the acid catalyst used for the alkylation. When operating in ^ liquid phase "is executed · the absorption at low temperature and low hydrocarbon diluent, is not extracted so that isobutylene from the acid phase · Acid from about 62 #iger H ₂ S (K concentration, a reaction mixture is formed, which contains about 35 ° isobutylene.

Because a significant amount of heat is released by the absorption of the olefins in acid, it is necessary to cool the absorption stage in order to keep the temperature in the desired range ssu keep"

The cooling of this and the following absorption stages is achieved by cooling the feed- flow for the absorption tower and / or by cooling the material in the absorption stage either achieved by evaporative cooling or by indirect heat exchange methods · Liquid can be removed from the Absorption system withdrawn, cooled by indirect heat exchange and returned to the absorber

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· The cooling liquid can be separated by a Cooling system can be replaced, or cooling can be achieved by a process flow · After a When this process is carried out, the hydrocarbon which flows out of the alkylation zone is depressurized, in order to make one end of the liquid hydrocarbon evaporate and the resultant To cool down the system of liquid and vapor «The resulting cooled liquid and vapor Hydrocarbon is in direct heat exchange with a stream in the heat mixture for the Absorption is introduced and causes the mixture to cool down.

Separation of isobutylene

Although various hydrocarbon solvents and inert purge gases to take off or Extracting the absorbed isobutylene from the diluted Sulfuric acid has been found to be a beneficial solvent isobutylene is. Other solvents, such as propane or η-butane, either have costly processing costs result in the removal of isobutylene or are harmful if they result in alkylation

together

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be introduced together with the isobutylene. Isobutylene is ideal in many ways »It is of low molecular weight, is readily available in large quantities as described in the process, and does not require separation of isobutylene which is introduced for alkylation. It is advantageous to use a high proportion of isobutylene for the stripping. In tests in the liquid phase, 10 moles of isobutane per mole of isobutylene absorbed give much better results than two moles, since a higher percentage is extracted and less polymer is formed.The results with 20 moles of isobutane are not much better than with 10 moles, mainly because because feeds the results to 10 moles are very good, "with 10 moles is the recovery of isobutylene about 90? 5 or higher with formation of less 5 i ~ polymers a high dosage of lösuiif Bnittels allows a low extraction temperature is used wodruch than the Results can be changed in such a way that less polymer is formed. And, as shown earlier, it is desirable. that the extraction or extraction temperature is not much higher than the absorption temperature. At lower temperatures and higher solvent dosages, if, in liquid

phase

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se worked mrö; Ötr ~ e Finlfat Ύοη isobutylene in addition to it. Free isobutylene extracted "JDiesey is highly desirable WSIL such Isobutylensulfat when it is alkylated, 100 f * SpSO. releases. Under ■ certain conditions, for example; if acid made available by the alkylation or by the extractor 34 or extractor 45 is used, this results in a lower total net consumption of acid ο Although liquid-liquid Es: tralrbion of isobutylene for the separation of ττοη isolnibylene from the absorption mixture of the diluted baths described above has been, the isobutylene can also be sucked out with isobutane in the vapor phase. " Isobutane is obtainable by the Sntisobiitaaisioren in the vapor phase at a high enough 'Sesiperatiir for ils extension level without additional I'lrwärflien "can be though of Semparatur Hztralroionsstiife vjoitsi * increased, if needed =

Isobutylene makes it easier to extract or take off * if the 'ÜGmpsreatiir is increased when taking it off * Ss' shows it. j ^ iocii corn ? Polymerizate, if the temperature increases and naturally the K03 iaii füi ^s ciaa Erwü ^ meii mid gutm. the cooling of the recycled acid increases »no large temperature difference between the abs or p-

t ion level

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+ "Ions stage and Auszugsatufe" there. A Teaperaturbersioh of about 38 ° to 93 ⁰ C can be used · As mentioned earlier, the strength of the absorption acid also has an impact on the time required for the desorption or extraction temperature.

When the extraction or stripping of isobutylene at a higher temperature than that Absorption of Isobutyl. 3, as is usually the case with the Pail is run, the recycle lean acid stream or the absorption zone must be cooled will. This can be effectively done in a number of ways, such as relaxation poor acid and part of the extracting isobutane or by adding a stream of Isobutane and relax, When the acid at one lower pressure than the absorption pressure is released, the cooled acid is returned to the absorber The loading material containing isobutylene is advantageously injected into the pump (s). After the reaction in the pump (s), the reaction mixture is sent to the separator.

Because the puncture of the absorber with dilute acid is to use isobutylene from the normal Butylene too. remove, it is not necessary

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the recovered isobutylene au alkylate, Bs can can be used for other purposes, such as "in the case of chemical Production »for example in the production of alcohols, butyl and special rubbers, intermediate products for cleaning agents, agents for improving the viscosity index of lubricating oil. if a high concentration of isobutylene is desired, the isobutylene can be used as the extraction medium from the isobutane Because the life of the acid in the isobutylene absorber is long, it tends to be separated to dilute with water that comes from the hydrocarbon feedstock is collected. Higher strength desiccant acid therefore becomes too added to the isobutylene absorber to achieve the desired 50-70% concentration of HpSO. to obtain" So fresh strong acid is added to the alkylation and there was *, exhausted alkylation catalyst acid of lead £ 5 or jlaffinate acid from lines 38 and 15 are added. A particularly desirable source for the feed acid is the exhausted acid raffinate containing acid alkyl sulfate and acid oil KoÄplex from extractor 34, optionally removing at least a portion of the polymeric oil by means not shown here can be. The oil can be made by adding

What s e i ·

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Water removed, leaving the polymeric separates oil, through absorption with an effective agent such as biochar, calcium carbonate and balance skat aly s ator for the liquid catalytic Cracking from silica-alumina or by salting out with inorganic ones. Salt. Preferably only one Part of the water that is necessary to effect separation of the polymeric oil is applied and the the exact proportion that is necessary depends on the composition of the exhausted acid; In cases in which the acid that is in the absorber 11 with dilute Acid was used to separate the polymeric oil that is normally lead with acid is linked as a complex, separated polymeric oil is from the system or from the polymer removed in line 16 before being fed to the alkylation.

n-butylene absorber

The 'charge for the n-butylene ab- • orber is the outflow of the isobutylene absorber, the n-butylenes alone or with propylene and any contains additional 0, - or ^, - hydrocarbons. The feed for the n-butylene absorber

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can with others. Olefin inflows that are essentially are free of isobutylene, supplemented "

The n-butylene absorption can be in Vapor phase as well as in liquid phase or in a Combination of the two phases are carried out. For example, for a higher conversion of the acid too Dialkyl sulfates part of the absorption in the vapor phase are carried out and the liquid phase for the final part of the absorption stage follow · cooling of the The absorption stage can, if desired, be carried out by introducing all or part of the charge from it or foreign hydrocarbons »such as propane, in the liquid phase and allowing it to evaporate due to the heat of reaction can be achieved in the absorber. Cooling can also be done using feed inflows to. the absorber, which has been cooled to a temperature below the reaction temperature of the absorber are »achieved, for example, the acid catalyst used can be used during an emulsion relaxation be subjected to the alkylation measure. cooling down can also be achieved by indirect heat exchange with cooling coils installed either in the absorber or outside be accomplished.

Acid catalyst used for the alkylation with a titratable acidity of 88

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Ms 93 weight percent, and with only 2 to 4 56 Water is the preferred acid feed to the absorption stage, although in some cases, for example "if Aaylene to be alkylated, a concentration of only 80 to 85 have ^c ß> can. Acid from other sources such as fresh acid, acid from chemical reactions, and acid from acid treatment of petroleum naphtha or lubricating oil can also be used · Acid with a concentration of only about 78 $ H ₂ SO. and a water content of up to $ 22> can also be used for the absorption of propylene and n-butylenes.

Substances such as absorber exhaust gas or the gas escaping during polymerizations are contained in the general substantial proportions of ethylene and also of inert components. Bs is known that Ethy «· len is disadvantageous for the alkylation because it causes an increasing consumption of acid. An effective one Means for treating ethylene-containing feed materials consists in the fact that they are the absorber run under conditions under which the ethylene does not react with the acid and so together removed with the inert components and not for

ge-alkylation / leads will. Such conditions are for

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phase, a short residence time »low temperatures, low partial pressure of ethylene,» it alkyl sulfates ■ diluted acids and acids of low concentration. The small amount of ethylene that makes acidic Ethylsulf at or diethyl sulfate reacts is out of the system in the raffinate or exhausted acid from the extractor removed after the n-butylene has been absorbed by strong acid. With substances that have a high concentration of propylene and butylene in relation to ethylene at a ratio of olefin to acid that is enough to form dialkyl sulfates, at least it can a fur of ethylene and mixed suIfats, such as. converted to itnyipropyl sulfate or ethyl butyl sulfate »The mixed sulfates alkylate satisfactorily with recovery of 100 percent sulfuric acid.

Its short dwell time and low temperatures lead to good results in the absorber and are preferred, although other factors significantly affect these factors Have · The strength of the contact treatment of the olefin with acid is of course very significant. Lingering pages of just a few seconds or minutes can be applied when a load is passing through a vessel with effective contact treatment

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On the other hand, a dwell time as long as an hour or more can be in a reactor with liquid phase or in one working in the blessing stream Packed column through gas removal of inert substances in the vapor phase and recycling of liquid reaction mixture applied from near the bottom of the column to halfway or higher in the column will.

A temperature range from -1 to 10 ⁰ O is sufficient for propylene, although less polymer is formed as a by-product at lower temperatures. For substances that contain n-butylene, a temperature τοη -6.6 to 4 »4 ⁰ C is preferred.

The isobutylene and n-butylene absorption stages can be carried out in a known device for contact treatment, for example in mixing vessels, centrifugal contact devices, co-current columns or two or more reactors equipped with mechanical stirring and working in countercurrent. Venn it is desirable to achieve high • ine implementation of acid su Diallcyleulfaten% u, vieletufige contact treatments Gegenetrose be before * is sufficient.

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Although a large part of the inert constituents Ie. the liquid product of the absorber if it is desired, the inert components can, for example by Reduction of the pressure above the liquid product and release of the evolved gases.

Only about 10 to 25 # of the entire Olefins, which are used in the entire process, have to be added to the absorber with sulfuric acid-SIäialy- · Sator, produced in dea dialkyl sulfate ia high yield is carried out in order to carry out the activity Ce11en the catalytic converter again * If so desired There is "flour" olefin feed by the AbB erb er Work too. let in the available acid To convert bialkyl sulfate, for example in the! Separation of olefin of inerts, can, this done and the entire acid phase from this absorber is added directly to the alkylation. In this lall enough Ölefin charge will be one another absorber with sulfuric acid catalyst for the conversion of the olefins to dialkyl sulfate, with the following ! Drenmaiig from the alkylii ^ uig ^ ö ^ aj ^ ainigungen before feeding the dialfcyl sulfates for alkylation.

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When carrying out the reaction of the olefin with the sulfuric acid catalyst at the same time and extraction of the resulting alkyl sulfates with a hydrocarbon in the gMchen kettle, such as in a counter-flow column, certain savings can be achieved and excellent results light-catalytic conditions are obtained are respected, so that although alkylating acid catalyst can be used for reaction with olefin in the presence of isobutane, the acid in contact with isobutane and olefin is below catalytic efficiency.

Extraction of the reaction product in the n-butylene absorber

Low temperatures and short times are advantageous for the extraction of the reaction product in the η-butylene absorber. For example, a temperature range of -1 to 10 ⁰ O with a few minutes' residence time is sufficient. However, good results are obtained at ambient temperatures of 30 to 38 ° C. The conditions depend somewhat on the absorption product and the olefin used for the absorption step.

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The extraction stage can be carried out in a device of a known type, for example in Äischgefäesen, spin contact devices or countercurrent colons, for example in a rotating disk contact device. Less efficient extraction can be used to achieve the same results if a small fraction Clay water is added to the reaction product in the absorber, for example up to about 10 percent by weight.

The separation of the dialkyl sulfate from the

Säar «~ t3l- £ eaktlonai>: rodiikt and reu water can on »» Holy ways to be guided, as in the pending ffSA patent application Serial Ir. 428 604, filed m 21 * Jenaer 1965, is disclosed. Sun example can be the He »kt ion mixture i» absorber old of a great witch water runned, old to one tohlenwaeeeretoff, like Ieobutsm, extracted, or es a low-level hydrogen solution can be cooled down.

Sialkylsulfates are more easily extracted with a hydrogen carbonate than the Bauren alkylsulfets. So is the wtoechenewert, conditions in the extraction process "MMMf" through which not only the glycyl fatty acid and the acid alkyl sulfate are extracted, and if possible only acid-oil

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Reaction product and water in the refined exhausted SM.ureph.ase and all alkyl sulfates in the extract or in the organic phase. Such conditions are the use of one Solvent dosage of the order of magnitude of six moles per mole of alkyl sulfate or higher, Raffinate recycling, multi-stage countercurrent extraction and optimal feed rate for a given Extraction vessel. The raffinate or the exhausted one Acid of the extraction stage contains water, acidic Alkyl sulfate, dialkyl sulfate and the reaction product of acid and polymeric oil, which during the alkylation and absorption stages is formed * The extract contains the hydrocarbon solvent, Dialkyl sulphate and a smaller proportion of acidic alkyl sulphate.

If the acid in the secondary olefin absorber for propylene and / or. n-Butylene has an acidity of about 75 to 90 ° £ with a water content of 25 to 10 <fo , or the raffinate or spent acid from the extractor has a composition such that the equivalent sulfuric acid and water have an acidity above about 50 $ with having a water content of about 50 % or less can contain most of that contained in the acidic alkyl sulfate

Olefins 009836/2128

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Olefins are deposited from the absorption mixture by their contact treatment either in the vapor phase or in a liquid phase with a hydrocarbon solvent or extractant such as isobutane. When the olefin is separated from the acidic alkyl sulfate, the dialkyl sulfate present converts to acidic alkyl sulfate. If the acid equivalent is too strong in the raffinate, would be so if the used Alkylierungssäure that about 2-4 $> contains water, used as for absorption by check yields a raffinate with an equivalent acid for about 85 i "is the raffinate fo ines diluted with water or dilute acid to a concentration of acid equivalent of about 70 to 85 with a water content of 30 to 15 io prior to extraction or separation of the olefin with isobutane. The resulting dilute acid raffinate is used to dilute the relatively strong acid catalyst used for the alkylation when more dilute acid is desired for the absorption of n-butylene. The raffinate acid can also be used as the feed acid for the isobutylene dilute acid absorber.

The more dilute the raffinate acid is in the extraction stage, the higher the relative

solubility 009836/2128

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solubility of the polymer oil in hydrocarbon solvents. The polymeric oil contaminant in the absorber-extractor extract is highly unsaturated and readily reacts with strong sulfuric acid, such as freshly "charged sulfuric acid used for the alkylation step or acid catalyst used for the alkylation, of about 90% concentration" the polymeric Oil can then be removed from the absorbent extract by acid treatment prior to its addition to alkylation and, optionally, after removal of any excess of unreacted olefin. Good results are obtained by acid treatment of the polymeric oil in isobutane solution with used alkylating acid of about 90% concentration at a temperature of 3O ⁰ C and in a time of one hour. a temperature that does not exceed 4-16 ⁰ C, and a short time of the order of a few minutes are beneficial. a very short time as the Mixing with a pressure release nozzle appears to occur to be sufficient. In order to guarantee an essentially complete removal of the oil and also of the water present, an excess of acid can be used. If too great an excess of acid is used

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some dialkyl sulfate is dissolved in it and is lost from the extract · This is not too serious because the dialkyl sulfate eit a Hydrocarbon solvent can be back extracted from the separated acid phase. At work in a continuous system, the acid phase can also be added to the main extraction column. As an alternative to the acid treatment of the extract, the entire reaction product can be stored in the absorber before the Ex- ■ traction of the dialkyl sulfates are treated with acid, to remove the polymeric oil au.

Alkylation

In general, the conditions for the alkylation stage are known per se. The bulk of the feed acid, however, for the alkylation ale alkyl sulfates which have arisen in the recovery section is introduced, and only a / minor proportion of the acid is used as the fresh feed acid with the usual concentration of 98 to 99.5 i ". Because the alkyl sulfates are essentially anhydrous, there is a tendency for the system's catalyst to have less water when the acid recovery process is used

salary

009836/2128

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to have content and generally to work with excellent quality in the sense that a lower end-point alkylation is achieved with higher octane values. Of course, if desired, less drying of the feeds can be used and in such a case the water content of the catalyst system can be as high as in normal operations without acid recovery. The sulfuric acid in the alkylation system is usually maintained in the range of about 88 to 95 percent by removing exhausted acid from the system. In a ■ multiple reactor system, the acid with the lowest concentration is preferentially withdrawn and sent to an acid recovery system.

When the acid equivalent after removal of the oil is of the spent acid from the extractor 34 in the order of $ 80 or more, and preferably 90 i> or more, a part can of the acid advantageously the alkylation reactor 37 together with a strong Beschiekungesäure of about 99 , 5% concentration. In this sequence of operations, a method of oil removal that does not increase the water content of the acidic component becomes like a

absorption 009836/2128

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- 33 - T 878

Absorption, or salting out »preferred. The proportion of acid that is returned to the alkylation reactor 37 grows by removing at least part of the water as well as the oil. This is achieved, for example, by adding a desicator filler, by distillation at low temperature or by adding both oil and also water removing agents such as anhydrous sodium chloride or anhydrous sodium sulfate. if Both oil and water have been removed from the exhausted acid by the extractor 43, that passes Remaining material consists mainly of sulfuric acid or its equivalent, acidic compound Alkylsulfato Preferably there will be enough water removed so that no more than about 3 percent by weight based on sulfuric acid equivalent is present are. If this has been done and oil has been removed to a certain extent, then should fresh feed acid of about 98 to 99.5 lower concentration to the alkylation reactor in a proportion that offsets the losses, such as mechanical losses and losses through reduction, are given.

A large excess of isobutane is used in the alkylation, for example 60 to

80 C09836 / 2128

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- 34 - S 878

80 percent by volume of the hydrocarbons in the AI-kylierungsreaktionsreaktionsmisehung. A large amount of isobutane has to be recovered and reused be recycled in the alkylation process. It is also, as previously described, for the Recovery process and usable for the extraction or separation of isobutylene. Additionally the olefin fed to the alkylation step in the form of alkyl sulfates becomes common further fresh olefin added to the alkylation stage. If, for example, propylene is used for the absorption stage, it is advantageous in the Use alkylation stage butylenes.

It has been found that the exhausted acid or raffinate surprisingly contains little water, which is to say that the acid equivalent is very strong. For example, in a pilot plant approach in which propylene was reacted with catalyst acid used for alkylation, the raffinate from the extractor contained 2.5 $ water, 11.2 $> acid polymeric oil, 11.4 # diisopropyl sulfate and 74.9 # propyl acid sulfate. Fresh acid fed to the alkylation reactor was 97.5% concentration with $ 2.5 water. The alkylating acid of the system or

the 009836/2128

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the acid catalyst used for the alkylation, which was added to the propylene absorber, gave 91.0 # H ₂ SO, ¹ ^ ^{βηΐ1ι1β1ΐ 2} f7 # water and 7 »2 $ acid-oil complex on titration. Because the Diisopropylsulfat 53 $> ^H 2 ^S0 4 ^ä ^ ^{uivalen 't is fc-propyl} sulfate and the acid is equivalent to 70 # H ₂ SO-, had the raffinate a Säurefjuivalent of about 96 #, wherein the acidic propyl sulfate and the Diisopropylsulfat as Säureätiuivalente were considered. It appears that the content of diisopropyl sulfate and acidic propyl sulfate is due to the high acidity equivalent of 96 i » «. The same result is obtained when butylenes are added to the absorber. Sb is very desirable, the alkylsul-

fate to be extracted almost completely from the raffinate, because unextracted material, on the other hand, results in a loss of olefin or possible alkylate and acid High recoveries of the extracted alkyl sulfates can be achieved through further reactions of the raffinate with an olefin such as propylene or n-butylene in the same manner as for the n-butylene absorber has been described. In the case of such an absorption, your prepyl sulfate "remains" is converted to diisopropyl sulfate, which is easier is extracted as sauisss propyl sulfate. Further

Has 009836/2128

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the remaining raffinate after re-extraction of dialkyl sulfate has a lower acidity equivalent »which promotes the extraction of alkyl sulfate. In this method can 90 i> dee acid equivalent and an appropriate portion dee olefin recovered and the alkylation sugeführt · This recovery of other alkyl sulfates, by absorption with raffinate acid may be continued until the Aciditätsäquivalent so low wirdι that the resulting acidic material " is primarily acidic alkyl sulfate, treated with additional olefin whose concentration is approximately 70 i> is not more reactive at ambient temperatures to formation of secondary olefins. The reaction can also be continued by using more reactive olefins or olefin compounds for the conversion of the raffinate acid ₉ such as butylene, amylenes or their compounds. Lower temperatures promote equilibrium so that a high concentration of dialkyl sulfate can be obtained if so desired. If the raffinate BjLt of the given analysis has reacted again with propylene under conditions in which about 90% of acidic propyl sulfate are converted to diisopropyl-βulfate, the acidity equivalent is 67 * fa% with only water and acid

Propyl sulfate 009836/2129

- 37 - I 878

15S359S

Eropyl sulfate should be considered. The remaining 10 % of the raffinate with an acidity equivalent of $ 67. Removal of the dialkyl sulfate results in analysis of 11.1 $ water, 35.3 $ acid propyl sulfate, a trace of. Diisopropyl sulfate and 55.6 ^ acid-oil koi & plex. Finally, a raffinate is produced which consists essentially of water and an acid-oil complex with a reduced proportion of acidic alkyl sulfate. When this has been performed, the net displacement ^ smoke is of acid approximately 8 »25 g per 3785 cm ³ alkyl compound.

The reactions that affect the conversion of sulfuric acid to hono- and dialkyl sulfates, are such that the raffinate used in the reaction of the alkylating acid with a secondary Olefin is strong enough in acidity or sufficient acidic alkyl sulfate compared to dialkyl sulfate contains so that additional reaction old olefin takes place · Additional recovery of ron Acid and olefin can be produced by reaction of the raffinate with additional olefin and subsequent extraction of the dialkyl sulfate can be obtained Bs is advantageous, the dialkyl sulfate from the second Raffinate with a hydrocarbon solvent, such as isobutane, but also other suitable

nete 00S836 / 2128

~ Λβ - T 878

some means can be used for separation, like a dilution bit of water and salting out · Although a maximum amount of benefit by using a separate absorber »can be obtained for the treatment of the raffinate from the extraction stage, can be the goal of corrosive olefin recovery and acid from the raffinate can be obtained in part by supplying a portion of the raffinate therefrom B extractor to a multi-stage Gregens & romabsorptionssystem, preferably near the final stage where olefin reacts with acidic alkyl sulfate of the raffinate. the acidic phase from absorption is extracted as usual

example

In the following example, the data shown in Table I feed materials listed in the one shown Apparatus used

Table I.

Plus candy volume percentage 0.1 Leobutylene butylene
Be s chicklings st off Be echickunßs etoff 2.7 Propylene 6.6 34.6 propane 4.0 15.9 Isobutane 24.5 Isobutylene 17.0

009836/2128

n-butylenes

BATH ORIGINAL

- 39 - ϊ 878

(Continued τοη Table I)

Isobutylene Butylene Beechickungastoff Beechickungastoff

n-butylenes 33.4 32.4 n-butane 14.5 11.0 Pentenes 0.0 3.3

Geeaat amount 100.0 100.0

Ieobutylene is used as a feedstock in ice «proportion τοη 17.63 * 10J-em 'per lay in

Steam fora in the absorber U, which contains 65 bio 70 i » Behulfeleäure, introduced at 24 ⁰ C and with a strength tone 1056 g per om ² . The savre phase το »absorber 11, which contains essentially all of the isobutylene, is passed into an extractor in which 67 Ί · of the isobutylene are sucked out by the acid in the liquid phase at 63 ° with 1 moles of isobutane per mole of isobutylene. The isobutane is obtained from an alkylation with a diisobutanizing agent. The isobutane phase of the separator, which contains Ieobutylene and acidic Ieobutyl sulphate, is passed through the alkylation zone 37.The acidic phase of the extractor that is sucked out is cooled and cleaned with dilute acid down to the absorber.

led back. 009836/2128

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returned. The sulfuric acid alkylation catalyst with a titratable degree of acidity of 90 56 also becomes the absorber of 11 bit dilute acid in a proportion which is sufficient to increase the sulfuric acid content of the acid in the absorber at 65 to 70 $. The acid tends to be weakened by the water contained in the hydrocarbon feeds and also due to the loss of acid in the form of acidic isobutyl sulfate in the separator.

• 7 The gaseous effluent that is 16.29 · 10

oar per day, from the weak acid absorber 11 which is essentially free of isobutylene and contains essentially all propylene and all 11-butylenes which have been introduced into the dilute absorber is condensed and passed through the absorber 22 , which in the liquid phase feei -I ⁰ G and with a strength of 3520 g per

ρ
cm works. The used alkylation catalyst with 90 # titratable acidity is also fed to the absorber 22 at a rate of 4-5879137 g per day. The separated acidic phase, which contains dialkyl sulfates, is passed through a counter-flow extractor, which at 1O ⁰ G and ntt one

ο
Strength of 5280 g per cm works. Nine moles of isobutane

Per 009836/2128

BAD ORiGiNAL

per mole of dialkyl sulfate are also added to the countercurrent extractor directed.

The separated extract phase, which contains isobutane and dialkyl sulfates, becomes the alkylation zone 37 headed. The raffinate phase, the alkylation of impurities from acid-polymeric oil complex and contains water and alkyl sulfates withdrawn as exhausted acid in addition to the isobutylene from absorber 11 and the dialkyl sulfates

7 "3

from the B extractor 34 will be 66.69 · 10 * onr per day of butylene feed to alkylation zone 37. Isobutane charge and 4365.18 kg per day 99.0% white sulfuric acid are also passed to the ajylation zone 37.

The 4365.18 ^ g of 99.0 ^ iger acid run

addition to 22.75 g per 7.78. 10 * cm 'alkyl compound.

The production of the alky! Connection is 71 »8 .10 '

• z 7 3

oar per day, of which 4.10 · 10 are of isobutylene of the isobutylene loading material that was introduced into the absorber 11 with sehwacker acid.

7 ■?

has been presented, 12.01. 10 'cm ^ of propylene and

n-Butylenes, which in the absorber 22 act as the alkylation catalyst have been introduced, manufactured and 55.69. 10 'cm' from the butylene feed, which has been fed directly to the alkylation,

manufactured 009836/2128

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produced '. The debutanized JLLkylation product has an investigation octane number (Research Octane) τοη 96.7 in the pure state and of 108.2 with 3.0 car tetraethyl lead, and an engine oetane number of 94.0 in pure condition and 107.5 with 3 ear tetraethyl lead.

Patent claims

009836/2126

BATH ORIGINAL.

Claims (1)

- 43 - T 878 Claims ι 1. Terfahren but alkylating an isoparaffine bit an olefin in the presence of an Sulfuric acid catalysts in an alkylation zone that contains a reaction mixture, the isoparaffin, olefin, alkyl sulfate and sulfuric acid contains, the effectiveness of said sulfuric acid is impaired by the accumulation of τοη alkylation impurities, and the Effectiveness of the sulfuric acid mentioned by contact treatment of at least part of the sulfur-acid catalyst, which has been separated from the reaction mixture mentioned, with olefin-forming s Alkyl sulfates is restored, the alkyl sulfate by said alkylation sone marked by Contact treatment of an olefin feed, the 009836/2128 isobutylene - 44 - T 878 Contains isobutylene and straight chain olefin, with sulfuric acid at a concentration of 50 Me 70 percent by weight sulfuric acid and 30 to 50 percent by weight water in a first absorption zone, Peeling off said first absorption bone a first absorption effluent as a hydrocarbon phase containing at least a portion of said straight-chain olefin, and one first absorption effluent as an acidic phase containing absorbed isobutylene, Contact treatment of at least a part of said first phase present as hydrocarbon st) ff phase Absorption discharge with the said Sulfuric acid catalyst in a second absorption zone, causing the formation of alkyl sulfates is effected, Withdrawal from said second absorption zone a second absorption flow as hydrocarbon substance phase and a second absorption effluent as acidic phase, the alkyl sulfates and alkylation impurities contains, Separation of the alkyl sulfates from the above-mentioned absorption effluent present as an acidic phase and the alkylation impurities and 009836/2128 - 45 - T 878 and passing in the thus separated alkyl sulfates to said alkylation zone. 2o method according to claim 1, characterized in, that said second absorption effluent, which is present as a hydrocarbon phase is passed to said alkylation zone. 3. The method according to claims 1 and 2, characterized in that said as acidic Phase present second absorption effluent in contact with a paraffinic hydrocarbon is brought, whereby the formation of a hydrocarbon extract phase, the dialkyl sulfates, including dibutyl sulfates, and one acidic raffinate phase, the alkylation impurities contains, is effected. 4. The method according to claim 3 »characterized in that that said paraffinic solvent contains isobutane and said hydrocarbon extract phase is passed to said alkylation zone. 5. Method according to one of the preceding Claims , 009836/2128 - 46 - T 878 Claims, characterized in that said first absorption effluent present as an acid phase is brought into contact with a paraffinic hydrocarbon in a draw-off zone, whereby an effluent of a hydrocarbon withdrawal zone containing isobutylene and an effluent of a acid discharge zone are formed and the said outflow of the acid discharge zone to the said first absorption zone is returned. 6. The method according to claim 5, characterized in that said paraffinic Contains hydrocarbon isobutane and said effluent from the hydrocarbon extraction zone to the called alkylation zone is passed. 7 * Method according to one of the preceding claims, characterized in that said Hydrocarbon phase of the second absorption effluent is brought into contact with the sulfuric acid catalyst, thereby extracting the dissolved AlkylationB impurities is effected. 8. The method according to any one of the preceding claims, characterized in that at least 009836/2128 - 47 - ϊ 878 1593595 a share of the acidic raffinate phase mentioned and the called first absorption sine is conducted 9 · The method according to one of the preceding claims, characterized in that »the β is at least a part of the acidic ones mentioned. Raffinate phase with water tu a Aciditätsi uiralent-τ on about 70 to 85 weight percent EUBO. Is thinned, and the diluted raffinate is brought into contact with a paraffinic hydrocarbon in an extraction zone "whereby the formation of an outflow from a hydrocarbon extraction zone which contains an olefin" and an outflow of an acidic extract with an acidity in the range of about 70 to 83 Proportion of weight H ₂ SO. is effected. 10. The method according to claim 9, characterized in that said paraffinic hydrocarbon contains isobutane and said effluent of the hydrocarbon extract zone is passed to said alkylation zone. 11. Do the driving. Claim 9 or 10, characterized in that at least part of the mentioned 009836/2128 BAD ORIGINAL ^ - 48 - T 878 said effluent of the acid extraction zone is subjected to hydrolysis, whereby formation of a Hydrolysis product containing alcohols "is effected, and the said alcohols from the said Hydrolysis product are separated. 12. Method according to one of the preceding Claims characterized in that an isoparaffin is alkylated with one based on olefin Material in the presence of a sulfuric acid catalyst in an alkylation reaction zone which is a Reaction mixture kept in the liquid phase with a hydrocarbon and an acidic emulsion contains of reactants, said catalyst contaminated with alkylation impurities becomes, the emulsion outflow, which is a part contains the reaction mixture mentioned, of the said reaction zone is withdrawn, and at least part of said emulsion effluent in an acidic phase, which contains alkylation impurities, and a hydrocarbon phase are separated is, a part of said acidic phase is passed to a multistage countercurrent absorber, in wherein said acidic phase is brought into contact with an olefin, whereby a reaction product educated 009836/2128 BATH ORIGINAL - 49 - T 878 Ϊ593599 is formed, and said reaction product with a hydrocarbon solvent is extracted, creating an acidic raffinate phase »the water and acidic alkyl sulfate, and a hydrocarbon phase are formed, and that advantageously a part of said acidic raffinate phase in the aforementioned multistage countercurrent absorption system is passed, whereby reaction of at least a part of said acidic alkyl sulfate is effected with said olefin with the formation of dialkyl sulfates. 009836/2128
BATH ORIGINAL • HfJ » SO L e r s e i t e