US2235589A

US2235589A - Process for extracting and recovering nicoting and other organic substances from tobacco

Info

Publication number: US2235589A
Application number: US219483A
Authority: US
Inventors: Rader Jennie Campbell
Original assignee: CHEMICAL EXTRACTION CORP
Current assignee: CHEMICAL EXTRACTION Corp
Priority date: 1938-07-15
Filing date: 1938-07-15
Publication date: 1941-03-18
Anticipated expiration: 1958-03-18

Description

l.. M. RADER 2,235,589

COTINE AND March 1S, 1941.

PROCESS FOR EXTRACTING AND RECOVERING NI OTHER ORLXNC SUBSTANCES FROM TOBACCO Filed July l5, 1958 Patented Mar. 18, 1941 vU NITED STATES PATENT OFFICE 'PROCESS FOR .EXTRACTING AND RECOVER- ING NICOTINE AND OTHER ORGANIC SUB- STNCES FROM TOBACCO tucky Application `iuly Vl5, 1938,'Seria1N0. 219,433

6 Claims.

The invention relates to the "processingfof tobacco and more particularly has reference 'to 'a method 'for removing or extracting various organic compounds therefrom.

Numerous processes have been developed .for the extraction of nicotine from tobacco. These have 'been 'designed A.primarily to produce a socalled denicotinized `tobacco or for the purpose of obtaining nicotine for lcommercial uses. I-IoW- ever, what ever may fbe their purpose, Vsuch extraction processes have resulted in costly products, and in so far as denicotinized tobacco is concerned an inferior one, Vdue to -their low extraction .yield of nicotine and Yalso their complicated procedure.

'.Chl'orophyll, .the green coloring matter yof plants, has also been extracted. However, 'no processes for obtaining it from tobacco were known to the inventor prior to the invention herein. This substance, chlorophyll, which is fextremely costly, has `been rendered so by the small amount of the 'same which occurs in plants, its relatively low extraction :yield and the 'complicated processes heretofore devised dor obtaining it.

Itis hence the imajor object of this yinvention to provide :a vmethod for extracting various organic compounds from tobacco.

An equally important object Aof the invention is the provision of a method for the extraction of heterocyli'c compounds from tobacco While pr'eparing or leaving the same in 4condition for the subsequent extraction of vrother compounds and substances.

.Another object Aof the invention `is to provide for the complete destruction of the cellular structure of .tobacco .in a process forextracting various organic compounds therefrom.

Still another object of the invention is, in a process for extracting lorganic compounds from tobacco, to destroy the "cellular structure Yof the tobacco under treatment `luy subjecting it to a vacuum and steam treatment.

Yet another object of the invention is to vdevise M a method. yfor extracting and recovering organic tobaccoafter `the addition of the ammonia which combines with'certa-in ofthe constituents remaining in the tobacco to yfor-m .ammoniafsalts and dissolving the freed compounds in a suitable hydrooarbon oil so as to permit. their recovery.

Still fa further object `of the invention 1s to provide an extraction process `for recovering organic. compounds from tobacco, wherein tobacco -1s A further object `of the invention is to provide a completely denicotinized tobacco and a imethod for producing the same. f

With these and other objects in view the invention-consists in the method to be hereinafter set forth and'claimed with the understanding that the steps thereof, the apparatus 'described for carrying them out, the reactants Vand solvents used as Well as their quantities may be 'widely variedby'those `sliilled'in the art vwithout departying from the spirit of the invention lor the scope of 'the claims appended hereto.

Briefly the invention comprehends a process for extracting `the heterocyclic constituents of tobacco, 'nicotine tand chlorophyll, Vfrom the same -while preparing or leaving the 'tobacco `in :a condition for further processing'to'obtain'orgianic and inorganic products. vOne vmanner Yof practically effecting this concept `is 'to draw a vacuum in the tobacco loaded l'container compartment of a suitable extractor mechanism. Steam is suddenly admitted into the compartment until the vacuum is half satisfied, after this gaseous ammonia is injected into the compartment. In most 'instances this will either wholly-destroy the vacuum or yraisea slight :pressure'in the compartment. A Vlight hydrocarbon'oil is now introduced, the tobacco 'having been subjected to violent agitation from a timeprior to the drawing yof the vacuum. After 'sucient agitation it will 'be yfound. thatall of `the nicotine and chlorophyll contained inthe tobacco have been freed therefrom and have been `taken up or dissolved in the oil while the ammoniavhas combined with some of the remainingconstituents of the tobacco to form ammonia salts with them, as for example salts of certain of .the polybasic acids such as oxalic, malic, and citric acids.

rrIo recover .the nicotine kand chlorophyll the entire/contents lof theextractor are dumped into a centrifuge and the oil is centrifuged off and sent to a clarifier. The tobacco in the centrifuge is then subjected to washing with clean or wash oil which is also centrifuged until the tobacco is in as dry a state as possible, the removed oil also being sent to the clarifier. After clarification both the original and the Wash oils are ready to have the nicotine Iand chlorophyll removed therefrom. Nicotine is extracted as a precipitated nicotine sulphate by the addition of sulphuric acid and Water to the oil While the chlorophyll is obtained, after the nicotine removal, by distillation of the oil and as a still deposit. Such distillation also recovers the oil employed in the process for reuse.

The invention also contemplates further treatment of the tobacco left in the centrifuge, which despite washing and centrifuging still contain some oil, so called center oil. removing this oil this denicotinized tobacco is placed in a second extractor where on the application of heat the oil is volatilized and sent to storage tank for reuse. There now remains an oil free denicotinized tobacco which may be used as such or which is in condition for further processing to recover all of the valuable constituents remaining therein. Where such recovery is carried out the extraction results in the complete destruction of the tobacco to cellulose.

In order to make the invention more clearly understood, there is shown in the accompanying drawing, means for carrying the same into practical effect without limiting the improvements in their useful applications to the particular constructions which, for the purpose of explanation have been made the subject of illustration.

In the drawing:

The figure shows a flow sheet for a plant designed to carry out the process of this invention.

Throughout the drawing similar reference numerals refer to like parts and elements shown on the flow sheet.

In carrying out the invention tobacco in the raw state, either shredded or ground or in the whole leaf or in stems is loaded onto conveyor I and by means of the elevator 2 is deposited into a storage bin 3 from whence it is introduced into one or more extractors 4.

The extractor or extractors 4 are connected through a pipe line 5 to a proper means for drawing a vacuum within the tobacco containing compartment thereof and also have connected thereto a pipe line 6 through which steam and then ammonia may be injected therein from any suitable sources of supply. In addition a pipe line 1, from an oil storage tank 8 leads into the extractors or extractor in order that oil from the storage tank may be introduced into each extractor in any well known manner.

Each extractor may be of any usual design. It is required however that the extractor or extractors be so constructed that a vacuum may be drawn in the tobacco containing compartment and also that they be able to withstand a slight pressure above atmospheric in the compartment. Further each extractor must be constructed so as toprovide for the violent agitation of the tobacco, as for example by rotation of the tobacco containing compartment and/or beating of the tobacco by paddles or blades mounted for rotation therein.

After an extractor 4 is loaded, violent agitation of the tobacco is usually begun, and a vacuum is drawn in the tobacco compartment through the vacuum line 5. This vacuum is maintained for To the end of tinued until upon analysis of the oil it is found that all of the nicotine displaced or freed from the tobacco has been dissolved in the oil. Instead of beginning agitation of the tobacco as soon as the extractor is loaded, if desired, this step in the process may be delayed until after the addition of the oil to the extractor.

In explanation of the extraction steps of the process, it would appear that the vacuum and steam treatment causes the complete destruction of the cellular structure of the tobacco as distinguished from the partial destruction, or disruption, or modification of the cells thereof. With the treatment just described, it would seem that the ammonia, When added, frees or displaces the entire nicotine and chlorophyll content of the tobacco from the plant after which action it chemically combines with certain of the constituents remaining in the tobacco by forming ammonia salts with them. The action occurring cn the addition of the ammonia proceeds with such rapidity that it may well be that the nicotine and the chlorophyll are freed either simultaneously or separately. In any event, that the nicotine and the chlorophyll are freed is borne out by the fact that no traces of them are found in the tobacco after such processing. 'Ihe freed nicotine and chlorophyll are dissolved by the oil and it is from this solution that these substances are recovered.

Where the process is practiced with a tobacco having a 4% nicotine content a vacuum of about 26 inches drawn on the extractor has been found to work very satisfactory. The size or degree of the vacuum is primarily determined upon the fact that after half of it is satisfied by steam there must be sufficient remaining space in the extractor to permit the introduction of ammonia gas, in slight excess of the theoretical amount needed to satisfy the nicotine content of the tobacco, without raising a pressure in the extractor which is much over normal. In the apparatus employed, where it is loaded with 500 pounds of tobacco having a 4% nicotine content the result of the injection of the steam and ammonia is to create a very slight pressure, less than a pound, in the extractor. This is usually the case in all instances resulting from following the general guide for determining the amount of the vacuum. Actually whether the tobacco compartment is under a vacuum or a pressure after the steam and ammonia treatment is immaterial to the successful practice of the invention. The pressure is maintained as low as possible as a practical mechanical matter.

A vacuum of 26 inches has been mentioned. This is based on the treatment of 500 pounds of tobacco having a 4% nicotine content in an extractor having a capacity of 87.132 cubic feet. It is important to note that the invention may be just as successfully practiced should a higher vacuum be drawn and for that matter .even a somewhat lower one.

fIhere has been found that in `determining the amount of ammonia needed to cause complete extraction of nicotine and chlorophyll it is necessary to consider only the nicotine content of elevator I2.

the tobacco. Also, complete extraction success has been had using 0.5 vpound cf ammonia, gas at N. T. P. per 100 pounds of tobacco with ,a nicotine content of 4% or in :other Words 0.5 pound yof ammonia for every 4 pounds'of nicotine is needed. :'Io lgive this inlcuhic feet of gas at N. T. P., 10.518 cuhic `feet ,of ammonia per 100 pounds or 52.59 cubic feet of ammonia per 500 pounds of 4% nicotine tobacco is necessary. In practice yammonia in slight excess of the theoretical amount needed to satisfy the nicotine coutent of the tobacco is employed. The figures given in the foregoing are working quantities and a'l-l include this excess.

As already mentioned a solvent is used for extracting the replaced nicotine and chlorophyll. Any light hydrocarbon oil similar to kerosene is employed :for this purpose. For example, deodorized kerosene and hydrogen-ated naphtha have heen found to work effectively. With a 4% nicotine tobacco 3 pounds of oil to 1 pound of tobacco are injected into the extractor. Where a tobacco with a lower nicotine content is pro-cessed a less amount of oil per pound of tobacco may te used although it should he noted that the only effect on the invention of the employment of oil in excess oi that needed is to increase the processing costs of the extracted products.

Violent agitation of ,thetobacco has been 1described. The purpose of this is to allow the steam, ammonia, and oil to he quickly distributed throughout the tobacco. Also it hastens the dissolving of the nicotine and the `chlorophyll hy lthe oil land generally speeds up the time cycle in plant operati-on. Agitation is continuous for from 15 minutes or even less to about 30 minutes. time is determined icy the amount of tobacco being treated, its nicotine content and the physicalV form and condition of the tobacco, :as for example its age and curing.

In any event the lagitation period 'is easily and quickly Iascertained by analysis of the solvent oil unt-il it is found that the nicotine lcontent of the oil equals the nicotine content of the tobacco undergoing processing, upon which, agitation is arrested. However, no harm willioe done to the tobacco should agitation continue longer than is actually necessary.

Aft-er suflcient agitation, the tobacco and oil is now dumped into a centrifuge 9 from tobacco bin I0 Where it has Iloeen conveyed from each extractor` 4 by means of the conveyor .IiI and Here the entire mass centrifuged at a very high speed to the en'd of removing from the tobacco as much of the solvent oil as is pos-sible. Oil removed lIcy this step in. the process is sent toa centrifugal separator or clarier I4, which will be presently mentioned. With the tobacco in the centrifuge in as dry a state as possible, 1 pound of clean or Wash oil per pound of tobacco is introduced therein from the storage tank 8 through the oil line II3, the entire centrifuging 'step just outlined I'oeing repeated and the wash oil being finally removed to the clarifier.

As mentioned th-e original oil used las a suivent and also the wash oil, both ,of which contain nicotine and chlorophyll, are passed through a clarifier I4. These oils are introduced therein by way of the oil line |15 which drains the centrifuge into an oil receiving tank 'I-6 from whence they are pumped Ithrough line Il to a surge bin I8 connected directly to the olarier I4. From the clarifier the oil is removed to a. mother liqucr tank I9 through exhaust line 2D .connected to the exhaust or outlet end of the clarifier. The l-cl-aricalti-on here as well as the centrifuging mentioned is done at very high speed. Its purpose is to remove tobacco dust and tobacco particles and also any pectin obtained from the tobacco, which might be in the oil.

Both oils, now :in the mother liquor tank are ready .tovhave the nicotine Iand chlorophyll removed from them. This is accomplished Iby feeding the oil through pipe line 2I into separating tanks 212 Where the nicotine is precipitated as nicotine sulphate hy the vaddition oi sulphuric acid and water to the oil from the aci-d tank 23 which is supplied by the acid egg 24. Generally sufficient acid is added to produce a 40% nicotine sulphate, the usual commercial grade.

fHoWever in practice it is sometimes found advisable vto extract a weaker sulphate and then subsequently concentrate it by adding pure nicotine thereto.

The separating or precipitate tanks can loe provided with agitators so that if desire-d the oil can loe agitated :during the addition of the acid and walter thereto. This is for the purpose yof thoroughly dispersing the acid and water through the oil.

The :oil kno-W remaining contains oniy chlorophyil in solution. This oil and the nicotine precipitate are removed from the lprecipitate tanks and are passed through line ,-215 to a clarifier 26. Here `on cl'airi-cat-ion the nicotine sulphate is removed as shown at A21 while the clarified oil is sent through line 2B to a recovery tank 29 which lis connected through a pipe line 30 to a recovery still 3|. The nicotine sulphate may be further processed for purificationk if Adesired or pure nicotine may be extracted therefrom 'in any well known manner.-

In the recovery still the oi-l is subjected to any usual distillation process so that it may be recovered for reuse. The puriied oil is then stored in storage tank 8,' connected to the still hy line 32, for this purpose. However, there remains in the still a crude chlorophyll Which of course is one of the compounds this invention is Idesigned to extract from the tobacco. y'Ihe crude chlorophyll is now remove-d from the still and isready for suitable refining.

Despite centrifuging after washing with clean oil there still remains in the tobacco in the centrifuge 9 a small amount of the Wash oil. This is the so called center oil. It is desired to obtain an oil free denicotinzed tobacco and to this end the treated tobacco in the centrifuge is transported to conveyor 33 where it is carried by elevator 34 to storage bin 35 for loading into one or more extractors 3i where the oil is removed by volatilization.

For applying heat to the tobacco, in order to volatilize the oil, each extractor 36 is jacketed and has the jacket connected to a steam line 3l from a hot Water tank 38 which is also heated by steam. If desired steam may also be injected directly into the tobacco in the container compartment of the extractor, although this is not necessary. Also instead of heating the jackets with steam, boiling Water from the hot Water tank may be employed for this purpose, but this practice is not preferred.' The volatilized oil is taken oi from the extractors through line 39 and sent to a separator tank where any Water that may be in the oil is removed and discarded through the outlet line 4I and the oil itself is sent direct to the storage tank 8 through line 42. It will be found that this volatilization step leaves a completely oil free denicotinized tobacco. Since this oil is the remainder of the clean wash oil left in the tobacco it will not need to be recovered by distillation before it may-again be used.

There is during the carrying out of the entire process, and despite oil recovery, a mechanical loss of about 1% of the amount of the `original oil used. To keep this loss as low as possible all equipment is provided with fume proof gasket joints. For the purpose of filling the storage tanks, a supply line 43 connects the tank to any suitable source of oil supply so that fresh oil may be discharged into the tank.

There now remains an oil free denicotinized,

tobacco, which may be removed for use as such, or is ready for further processing in order to free other constituents therefrom. This latter step, which does not form part of this invention, may be accomplished by injectingl steam and/or boiling Water into the extractor While the tobacco is violently agitated.

The value of the process may be realized when it is considered that the remaining tobacco on analysis will be found to be completely denicotinized. From this fact a high extraction yield should be expected. `That such is the case is clearly illustrated when it is pointed out that over many recorded runs in a pilot or test plant consistently Well over 31/2% of nicotine has been recovered from a tobacco (Kentucky tobacco) averaging a total content of 4% of nicotine or in other terms a recovery yield of 871/2% of the total nicotine content of the tobacco which total content has been entirely extracted from the tobacco. The size of this yield Will be appreciated When it is considered that the runs were made with a pilot plant Where there are many mechanical losses. While relatively high recovery yields for nicotine have been recorded in the past it should be noted that for yield comparison they have been obtained by methods possessing the disadvantage of failing to extract all of the nicotine and invariably leave the tobacco With at least a 1% nicotine content.

Recovery yields from the pilot plant of approximately 95% have been obtained and With commercial practice of the invention over 98% of the nicotine should be recovered. It should be noted that an analysis of the solvent oil after precipitation and separation of the nicotine Will show but the barest of a trace of nicotine remaining therein. However, whatever recovery yield is obtained, it should be constantly kept in mind that the invention is designed to extract all of the nicotine from tobacco for the purpose of vobtaining an inexpensive product and for preparing the tobacco for the extraction of its other constituents if such latter is desired. 1

At the present time but comparatively little is known about chlorophyll. At least, so far as the inventor was aware no attempts had been made to extract it from tobacco. 'Ihe chlorophyll content of any plant is of course relatively small and in the case of tobacco is less than that of the nicotine. Moreover the chlorophyll content of tobacco will vary with the condition of the tobacco as for example its age, kind and length of curing, and drying and other like factors. Even with pilot plant operation it has been possible to remove all of the chlorophyll from the tobacco treated, as is the case of the nicotine. This compound is in effect a by-product of the main nicotine extraction process. In the pilot plant, operation 2 to 3 pounds of crude chlorophyll per 100 pounds of Kentucky tobacco, which as lpointed out willaverage a nicotine content of 4%, has -been obtained.

From the foregoing it will be appreciated that there has been invented a novel process for extracting nicotine and chlorophyll from tobacco and one which can be performed cheaply and simply. The low cost of the extracted products is of course caused by the simplicity of the process as well as its effectiveness which results in a high yield and leaves the tobacco in a condition for further processing, to the end of removing all of the valuable constituents remaining therein.

Also important to note is the fact that should any step of the process be carried out in excess, as for example regarding the elements of time and amount or quantity, no harm is caused to the tobacco nor is the extraction yield of the products to be recovered effected.

While the preferred embodiment of the invention has been shown and described, it is to be understood that the invention is not confined to the specific method steps and the details of the construction of the apparatus for carrying out the method herein set forth, by Way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, Without departing from the spirit of the invention, or exceeding the scope of the appended claims.

There is claimed:

1. In a process for extracting nicotine and chlorophyll from tobacco the steps of, subjecting a processing compartment containing tobacco to a vacuum of about twenty-six inches Within the limit substantially as set forth, partially satisfying the vacuum with steam to an extent that by thereupon admitting suiicient gaseous ammonia at N. T. P. into the compartment to theoretically replace the nicotine content of the tobacco being processed the remaining vacuum will be satisfied, the tobacco at no time subjected to a temperature sufficient to destroy the chlorophyll.

2. In a process for extracting nicotine and chlorophyll from tobacco the steps of, subjecting a processing compartment containing tobacco to a vacuum of about twenty-six inches Within the limit substantially as set forth, partially satisfying the vacuum with steam to an extent that by thereupon admitting sufficient gaseous ammonia at N. T. P. into the compartment to theoretically 'replace the nicotine content of the tobacco being processed the remaining vacuum will besatisfied, such treatment of the tobacco freeing the nicotine and chlorophyll therefrom, and then injecting a solvent oil into the compartment to dissolve the freed compounds, the tobacco at no time subjected to a temperature sufficient to destroy the chlorophyll.

3. In a process for extracting nicotine and chlorophyll from tobacco the steps of, subjecting a processing compartment containing tobacco to a vacuum of about twenty-six inches within the limit substantially as set forth, partially satisfying the Vacuum with steam to an extent that by thereupon admitting sufficient gaseous arnmonia vat N. T. P. into the compartment to theoretically replace the nicotine content of the tobacco being processed the remaining vacuum will be satisfied, such treatment of the tobacco freeing the nicotine and chlorophyll therefrom, and then injecting a solvent oil into the compartment to dissolve the freed compounds, the tobacco being subjected to violent agitation during treatment, the tobacco at no time subjected to a temperature suicient to destroy the chlorophyll.

4. In a process for extracting nicotine and chlorophyll from tobacco the steps of, subjecting a processing compartment containing tobacco to a vacuum of about twenty-six inches Within the limit substantially as set forth, maintaining the tobacco under the vacuum drawn for a relatively short time, then partially satisfying the vacuum With steam to an extent that by thereupon admitting sufficient gaseous ammonia at N. 'I'. P. into the compartment to theoretically replace the nicotine content of the tobacco being processed the remaining vacuum Will be satisfied, the tobacco at no time subjected to a temperature sufl'icient to destroy the chlorophyll.

5. In a process for extracting nicotine and chlorophyll from tobacco the steps of, subjectingr a processing compartment containing tobacco to a vacuum of about twenty-six inches Within the limit substantially as set forth, maintaining the tobacco under the Vacuum drawn for approximately two minutes, then partially satisfying the vacuum with steam to an extent that by thereupon admitting sufficient gaseous ammonia at N. T. P. into the compartment to theoretically replace the nicotine content of the tobacco being processed the remaining vacuum Will be satisfied, the tobacco at no time subjected to a temperature sufcient to destroy the chlorophyll.

6. In a process for extracting nicotine and chlorophyll from tobacco freeing these compounds from tobacco by subjecting a processing compartment containing tobacco to a vacuum of about twenty-six inches Within the limit substantially as set forth, maintaining the vacuum for approximately two minutes, then partially satisfying the vacuum with steam to an extent that by thereupon admitting sumcient gaseous ammonia at N. T. P. into the compartment to theoretically replace the nicotine` content of the tobacco being processed the remaining vacuum Will be satised, and introducing a solvent hydrocarbon oil into the compartment to dissolve the freed nicotine and chlorophyll, the tobacco being violently agitated during this treatment and until all of the nicotine is in solution, and the tobacco at no time subjected to a temperature sufficient to destroy the chlorophyll.