CA1108552A - Extractive distillation recovery process - Google Patents

Extractive distillation recovery process

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Publication number
CA1108552A
CA1108552A CA303,600A CA303600A CA1108552A CA 1108552 A CA1108552 A CA 1108552A CA 303600 A CA303600 A CA 303600A CA 1108552 A CA1108552 A CA 1108552A
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CA
Canada
Prior art keywords
column
process according
water
products
steam
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA303,600A
Other languages
French (fr)
Inventor
Dieter W. Bruck
Harro Schlesmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bayer AG
Original Assignee
Bayer AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bayer AG filed Critical Bayer AG
Application granted granted Critical
Publication of CA1108552A publication Critical patent/CA1108552A/en
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D277/00—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings
    • C07D277/60—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings condensed with carbocyclic rings or ring systems
    • C07D277/62—Benzothiazoles
    • C07D277/68—Benzothiazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2
    • C07D277/70—Sulfur atoms
    • C07D277/72—2-Mercaptobenzothiazole
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/14—Fractional distillation or use of a fractionation or rectification column
    • B01D3/16—Fractionating columns in which vapour bubbles through liquid
    • B01D3/24—Fractionating columns in which vapour bubbles through liquid with sloping plates or elements mounted stepwise
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/34—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances
    • B01D3/38—Steam distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
    • C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
    • C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
    • C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
    • C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
    • C07C29/84—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation by extractive distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
    • C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
    • C07C37/70—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment
    • C07C37/74—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment by distillation
    • C07C37/76—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment by distillation by steam distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D235/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, condensed with other rings
    • C07D235/02—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, condensed with other rings condensed with carbocyclic rings or ring systems
    • C07D235/04—Benzimidazoles; Hydrogenated benzimidazoles
    • C07D235/24—Benzimidazoles; Hydrogenated benzimidazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2
    • C07D235/28—Sulfur atoms

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Extraction Or Liquid Replacement (AREA)
  • Heat Treatment Of Water, Waste Water Or Sewage (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)

Abstract

A PROCESS FOR RECOVERING STEAM-VOLATILE AND/OR WATER-SOLUBLE
ORGANIC PRODUCTS FROM MELTABLE RESIDUES OR SUSPENSIONS.

Abstract of the Disclosure A process for recovering steam-volatile and/or water-soluble organic and/or inorganic products from meltable residues or suspensions containing such products which comprises feeding the molten residue or suspension into a trickle plate column at a temperature of less than 250°C, extracting the said molten residue or suspension with steam and/or water condensate, condensing the mixture issuing at the top of the column, drawing off the remaining extracted melt or suspension and the descending aqueous phase at the bottom of the column and subsequent separation.

Description

~$~85~

The present invention relates to a process for recovering steam-volatile and/or water-soluble organic products from meltable residues or suspensions by extraction. More particularly, it relates to a process for the continuous separation of amines, alcohols, phenols, water-soluble organic and inorganic salts, such as, for example, common salt, the sodium salt of mercaptobenzthiazole (MBT) and mercaptobenzimidazole.
In many chemical reactions carried out industrially, a number of undesirable by-products, resins and/or salts are formed in addition to the desired end products.
In many cases, it is only possible to separate these residues in part from the unreacted starting materials and the end product. Thus, for example, the recovery of unreacted volatile starting materials by distil-lation in a thin-film evaporator will depend upon the viscosity of the residues. Non-volatile starting materials such as, for example salts of organic acids may usually be recovered only by highly expensive processes of extraction. If the residues contain inorganic salts, viscosity may only be obtained by using large proportions of the liquid starting materials even at high temperature.
The present invention now provides a process for recovering steam volatile or water-soluble, organic or inorganic products from meltable residues or suspensions containing these products by means of extraction, characterised in that extraction is carried out at a temperature below 250C
in such a way that the molten residue or the suspension is fed into a trickle plate column, extracted with steam or water condensate, the mixture issuing at the top of the column is condensed and the remaining extracted melt or suspension is drawn off together with the descending aqueous phase at the column bottom and separated.
In the process according to the present invention, compounds which form a homogeneous or heterogeneous azeotrope with water are designated as steam-volatile products. Salts of mineral and organic acids such as common _,_. -2-,~

5:~2 salt, sodium sulphate, the sodium salt of mercaptobenzthiazole and mercapto-benzimidazole are designated as water-soluble inorganic or organic products.
The removal of the volatile and/or soluble fractions from the melt-able residues or suspensions by means of steam distillation and extraction with water, or the condensate of water and the volatile fraction is desig-nated as extraction in the process according to the present invention.
In the accompanying drawings, Figure 1 shows a detail from a trickle plate column, illustrating the arrangement of the separating units; and Figures 2a and 2b show two possible arrangements for using a trickle plate column in the process of the invention.
The separator shown in Figure 1 is a trickle plate column which may be employed in the process of the present invention and is characterised by having a multiple arrangement of separating units ~c) consisting of a conical distributor (a) and a collector ~b). The design of such a suitable laboratory trickle plate column is described in for example the catalogue published by the company Normag ~1976 edition, page 79). It is advantageous for the process according to the present invention for the gas mixture issuing at the head of the column to condense only after rectification, and for the condensate , .

draining at the foot of the rectifying column to be used for the extraction. If the residues contain inorganic salts, a higher degree of efficiency is obtained in the upper section of the extr~ction column as a result of this step according to the invention. With a smaller number of plates, quantitative conversion of the salts from the resinous into the aqueous phase is quite feasible.
Temperatures of from 70 to 150C and pressures of from 0.5 to 10 bar, preferably 100C nnd about 1 bar are gener~lly convenient as extraction temperatures and pressures but higher temperatures of up to 250C and pressures of up to 30 bar may also be used if this is necessitated, due to the high melting point of the residue to be worked up.
However, the melting point of the residue or the suspension is normally already reduced at the first extraction stage plate by extracting the organic and inorganic salts so that a lower temperature is thereby sufficient for extraction.
The lower extraction temperature is generally influenced by the viscosity, ~ the resin.
Resins which may be recovered in the process according to the present invention include, for example, those organic products which are formed as non-usable by-products during the production of, for example, sulphenic amides. The viscosity of these resins is important when selecting the extraction temperature and also the temperature in the apparatus separating the aqueous phase from the resinous phase.`Thus, for example, resins having a viscosity ~= 1 - 30 Le A 18 o60 - 4 -~8S52 Poise at between 90 and 75C, and also resins having a viscosity of up to 200 Poise may be extracted and separated by a suitable choice of the tempera-ture.
Quantitative conversion of the organic and inorganic salts into the aqueous phase drawn off at the foot of the column together with the re-sin, is obtained by suitable choice of the extraction stages (separating units in the trickle plate column). Whereas the resins may be baked after separating the phases, the organic acids may be recovered from the aqueous phase, for example by known precipitation processes.
A separating vessel whose temperature may be controlled is part-icularly convenient for separating the resinous phase from the aqueous phase.
However, other separating means such as, for example, centrifugal separators may be used.
The process according to the present invention is preferably carried out continuously.
A possible manner of carrying out the process according to the present invention is shown diagrammatically in Figure 2 and is described be-low.
The molten residue 1 is fed into, for example, from a trickle plate column 8. Steam 2 is simultaneously supplied at the bottom of the trickle plate column and extracts the steam volatile constituents from melt in the counter-flow. The gas mixture leaving the trickle plate column is then either condensed 3 (variation a) by flowing through a stripper 9 or is rectified (variation b) in a column 10. In this case, an enriched conden-sate may be drawn off as condensate 7 in variation b. In order to extract the organic and inorganic salts from the melt, either steam condensate 6 (variation a) or the condensate draining at the bottom of the rectification column 10 (variation b) is fed onto the top plate of the trickle plate column. The condensate draining at the bottom of the column 8 and contain-ing the salts is drawn off together with the remaining resin and is intro-~85~i2 duced into the separating vessel 11. After separating the phases, theaqueous and resinous phases may be removed continuously (via 5 and 4 respect-ively).
The proportions given in the following illustrative examples are parts by weight.
Example 1 The apparatus used corresponded to the embodiment shown dia-grammatically in Figure 2a.
650 parts of a melt of the average composition;
20.3 % of cyclohexylamine (CHA) 41.6 % of sodium salt of mercaptobenzthiazole (NaMBT) 31.4 % of resins which were formed by reacting NaMBT with CHA and chlorine at about 50 C;
viscosity at 80C about 15 Poise, 6.7 % of NaCl were fed each hour via the feed pipe 1 onto a trickle plate column having 20 separating units (plates) at a temperature of 130C.
On average, about 1956 parts of steam condensate at about 98C and 810 parts of steam at about 1.2 bar were simultaneously added each hour via the feed pipes 6 and 2 respectively.
The vapours leaving at the head of the trickle plate column were condensed after passing through a 50 cm high packed column 9 and, subsequently, removed via the pipe 3.
The resinous and aqueous phases draining at the foot of the -trickle plate column flowed into the separating vessel 11 which was cooled sufficiently for the resin to still just be drawn off in liquid form at a temperature of 80C, for improving separation of the phase.
At the beginning of the extraction process, water containing about
2 % of NaCl was placed in the separating bottle 11 to make it easier to start up the equipment.

,~, On average, about 835 parts of distillate and 192 parts of resin from the separating vessel as well as 2389 parts of aqueous phase of the following average composition were drawn off hourly.
Distillate: 15.8 % of CHA
0.1 % of unknown 84.1 % of H20 Resins containing about: 0.2 % of NaMBT
0.5 % of NaCl Aqueous Phase: 1.8 % of NaCl 11.8 % of NaMBT + resins 86.4 % of H20 Example 2 An apparatus of the type shown diagrammatically in the embodiment in Figure 2b was used for this example.
1150 parts of a melt drawn from the bottom of a thin-film evapor-ator having the average composition:
8.8 % of CHA
33.0 % of NaMBT
33.7 % of resins which were formed by reacting NaMBT with CHA and chlorine at about 50C; viscosity at 80C about 15 Poise 24.5 % of NaCl was fed each hour via the feed pipe 1 on to a trickle plate column 8 having 15 separating units at a temperature of about 150C.
An average of 3000 parts of steam at a pressure of 6 bar was simultaneously added hourly at the bottom of the trickle plate column via the pipe 6.
The vapours leaving the column 8 flowed into a 2 m packed column 10 and were rectified at a reflux ratio of about 4. The operating pressure (pressure at the top of the column 10) was 5 bar, and the temperature at the column top was about 140C. The distillate was removed via the pipe 7. The ~855Z

condensate draining from the packed column 10 was fed onto the trickle plate column as an extraction agent.
The resinous and aqueous phases draining at the bottom of the trickle plate column 8 were then fed into a cooled separating vessel (about 80C) which had been filled before beginning the experiment with 10 % common salt solution.
On average, about 383 parts of distillate and 369 parts of resin from the separating vessel and 3397 parts of aqueous phase of the following average composition were drawn off hourly:
Distillate: 26.4 % of C~IA
about 0.2 % of unknown 73.4 % of H20 Resins: <0.1 % of NaMBT
<0.01 % of NaCl Aqueous Phase: ~ 11.7 % of NaMBT + resins ~ 8.3 % of NaCl ~ 80.0 % of H20 Example 3 The apparatus used in Example 2 was used.
1100 parts of a melt having the average composition:
19.2 % of CHA
35.5 % of NaMBT
29.4 % of resins which were formed by reacting NaMBT with CHA and chlorine at about 50C;
viscosity at 80C about 15 Poise 15.9 % of NaCl was fed each hour via the feed pipe 1 on to the trickle plate column 8 at a temperature of about 130C. An average of 2615 parts of steam at 1.2 bar was added via the pipe 2.
At a head temperature of about 96C, a pressure of about 1 bar (measured at the condensor) and a reflux ratio of about 6, the following products were obtained on average:
Products Average Composition Distillate r~ 480 Parts 44 % CHA, 56 % H20 Resins: ~ 310 Parts NaMBT<0.2 %, NaCl<0.01 %
Aqueous Phase: ~ 2925 Parts about 14 % NaMBT + Resins, about 6 % NaCl about 80 % H2O
Example 4 The apparatus described in the Example 1 was employed but was modified by use of an additional separating vessel for separating the phases of the distillate. After placing water in this additional separating vessel and an approximately 10 % common salt solution in the separating vessel 11, about 2000 parts of a suspension of the average composition:
51 % of NaCl 20 % of sodium salt of mercaptobenzimidazole (NaMb) 19.7 % of isopropylphenol 9.3 % of resins (Elementary analysis: C = 56.7 %, H = 6.5 %, N = 10.3 %, O = 3 %, S = 23.5 %.
Viscosity 5 Poise at 80C) was fed hourly via feed pipe 1 onto the column 8 at a temperature of 80C.
About 4720 parts of steam at 1.2 bar was simultaneously added via the feed pipe 2. The vapours leaving the stripper 9 flowed after condensa-tion (temperature about 90C, pressure at the head of the column about 1 bar) into a separating vessel in which the isopropylphenol phase was separated from the aqueous phase. Although the isopropylphenol phase was drawn off as distillate, the aqueous phase flowed via the pipe 6 back into the trickle plate column again.
On average, about 397 parts of distillate and about 186 parts of resin from the separating vessel 11 and 6137 parts of aqueous phase of the following average composition were drawn off hourly:
Distillate: about 99.0 % of isopropylphenol about 1.0 % of H20 Resins containing about: 0.1 % of NaCl, 0.1 % NaMB
Aqueous Phase: about 16.6 % of NaCl 76.9 % of H20 6.5 % of NaMB + Resins Example 5 The modified apparatus according to Figure 2a and described in Example 4 was used. After placing water and a 10 % common salt solution in the separating vessel, about 1500 parts of a suspension of the average com-position:
51.6 % NaCl 20.2 % of NaMB-Salz 17.4 % of hexanol 1.4 % of H20 9.4 % of resins ~Elementary analysis: C = 56.7 %
H = 6.5 %, N = 10.3 %, O = 3 %, S = 23.5 %;
Viscosity 5 Poise at 80C
was fed hourly via the pipe 1 onto the colùmn 8 at a temperature of 80 C.
About 1850 parts of steam at 1.2 bar was simultaneously added via the pipe 2.
The vapours leaving the stripper 9 flowed after condensation (about 50C, pressure at column top about 1 bar) into a separating vessel in which the hexanol phase was separated from the aqueous phase. Although the hexanol phase was drawn off as distillate, the aqueous phase and about another 2.002 parts of hot water at 98C flowed back via the pipe 6 into the trickle plate column.
On average, about 281.7 parts of hexanol phase and about 134 parts of resin from the separating vessel 11 and about 4936 parts of aqueous phase of the following average composition were drawn off:

~ 855Z

Distillate: 92.5 % of hexanol 7-5 % of H20 Aqueous Phase: 15.7 % of NaCl 6.3 % of NaMB + Resins :-78-0 % of H20 :
.Resins: <0.1 % of NaCl, <0.1 % of NaMB.
, , ~
:

: ~

,`~ '' `: ': '~
~, : , J` "~ .

~'; ~ ''`,'`,' ~ . ` ,' :3 ~
. ',:

' : `

.~
~.

... . . . .. . -6. 3% of NaMB ~ resins 78. 0,~ of H20 Resins: ~ O. l,~ of NaCl ,~O. l,~ of N~IMB.

Le A l 9 o60 - 12

Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for recovering steam volatile or water-soluble, organic or inorganic products from meltable residues or suspensions containing these products by means of extraction, characterised in that extraction is carried out at a temperature below 250°C in such a way that the molten residue or the suspension is fed into a trickle plate column, extracted with steam or water condensate, the mixture issuing at the top of the column is con-densed and the remaining extracted melt or suspension is drawn off together with the descending aqueous phase at the column bottom and separated.
2. A process according to claim 1, characterised in that the molten residue contains suspended organic or inorganic water-soluble salts.
3. A process according to claim 1 or 2, characterised in that the water-soluble organic products are salts of sparingly soluble organic acids.
4. A process according to claim 1, characterised in that the steam volatile substances are alcohols, amines and phenols.
5. A process according to claim 1, 2 or 4, characterised in that the gas mixture issuing at the column top is condensed only after rectification and the condensate draining at the bottom of the rectification column is used for extraction.
6. A process according to claim 1, 2 or 4, characterised in that extract-ion is carried out at temperatures of from 70 to 250°C.
7. A process according to claim 1, 2 or 4, characterised in that extract-ion is carried out at pressures of from 0.5 to 30 bar.
8. A process according to claim 1, 2 or 4, characterised in that the process is carried out continuously.
CA303,600A 1977-05-20 1978-05-18 Extractive distillation recovery process Expired CA1108552A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19772722960 DE2722960A1 (en) 1977-05-20 1977-05-20 PROCESS FOR THE RECOVERY OF VAPORATIVE AND / OR WATER-SOLUBLE ORGANIC PRODUCTS FROM MELTABLE RESIDUES OR SUSPENSIONS
DEP2722960.3 1977-05-20

Publications (1)

Publication Number Publication Date
CA1108552A true CA1108552A (en) 1981-09-08

Family

ID=6009532

Family Applications (1)

Application Number Title Priority Date Filing Date
CA303,600A Expired CA1108552A (en) 1977-05-20 1978-05-18 Extractive distillation recovery process

Country Status (10)

Country Link
JP (1) JPS53142979A (en)
BE (1) BE867261A (en)
BR (1) BR7803173A (en)
CA (1) CA1108552A (en)
DE (1) DE2722960A1 (en)
ES (1) ES470032A1 (en)
FR (1) FR2390981A1 (en)
GB (1) GB1601637A (en)
IT (1) IT7849435A0 (en)
NL (1) NL7805450A (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4201628A (en) * 1977-10-07 1980-05-06 The Goodyear Tire & Rubber Company Separation apparatus
JPS60110715A (en) * 1983-11-18 1985-06-17 Hitachi Chem Co Ltd Production of selfcuring phenolic resin
GR1001403B (en) * 1993-01-14 1993-11-30 Georgios Foukakis Biological filter.
EP0607100B1 (en) * 1993-01-14 1998-06-03 FOUKAKIS, Georgios Filter for combustion fumes

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE297495C (en) * 1915-06-22 1917-04-23
US2444527A (en) * 1943-11-30 1948-07-06 Richard D Pomeroy Method for recovering organic acids from sour sewage sludge
US2455703A (en) * 1946-09-17 1948-12-07 Goodrich Co B F Process of purifying nuclear-chlorinated bis-phenols by steam distillation
FR1082921A (en) * 1952-06-19 1955-01-04 Motor-driven, cushion-shaped physiotherapeutic device
GB1182260A (en) * 1966-09-27 1970-02-25 William H Moss Res Ltd Separation of Phenolic Compounds from Reaction Mixtures.
JPS4942591A (en) * 1972-08-29 1974-04-22
DE2340566C2 (en) * 1973-08-10 1985-11-07 Peter, Siegfried, Prof.Dr., 8520 Erlangen Process for the separation of components from mixtures of substances with low vapor pressure with the aid of a compressed gas under supercritical conditions and another substance that influences the separation effect

Also Published As

Publication number Publication date
GB1601637A (en) 1981-11-04
FR2390981A1 (en) 1978-12-15
DE2722960A1 (en) 1978-12-07
BR7803173A (en) 1979-01-02
JPS53142979A (en) 1978-12-13
BE867261A (en) 1978-11-20
ES470032A1 (en) 1979-01-01
IT7849435A0 (en) 1978-05-18
NL7805450A (en) 1978-11-22

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