Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D251/00—Heterocyclic compounds containing 1,3,5-triazine rings
  • C07D251/02—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings
  • C07D251/12—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
  • C07D251/26—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with only hetero atoms directly attached to ring carbon atoms
  • C07D251/30—Only oxygen atoms
  • C07D251/36—Only oxygen atoms having halogen atoms directly attached to ring nitrogen atoms

Definitions

• Dichloroisocyanurates are well-known materials which are widely used as a source of available chlorine in solid bleaching, sanitizing and detergent compositions.
• the sodium and potassium salts are the most widely used in laundering compositions because they are very soluble and easily removed by rinsing.
• the sodium dichloroisocyanurate compounds are known to exist in three forms, namely, the anhydrous form, the monohydrate (containing approximately 7.6% water of hydration by weight), and the dihydrate (containing approximately 141% water of hydration by weight). See Symes, US. Pat. Nos. 3,035,056 and 3,035,057.
• One prior art procedure for producing sodium dichloroisocyanurate dihydrate involves the chlorination of trisodiumi socyanurate with gaseous chlorine.
• the dihydrate solids produced by chlorination are separated from the bulk of the aqueous phase by wellknown methods for separating solids from liquids, and then dried to remove uncombined water to produce dry sodium dichloroisocyanurate.
• Dihydrates produced in this manner have bulk densities of approximately 35 pounds/cubic foot or 0.56 grams/cubic centimeter. These dihydrates are effective as a source of available chlorine when mixed with components of solid bleaching and detergent compositions having the same bulk density.
• Brown et al teach mixing a dichlorocyanurate (in acid or salt form) with a synergistic carrier agent mixture of sodium tripolyphosphate and sodium sulfate decahydrate. This mixture is heated and cooled to form a slurry or plastic mass, which is then dried at high temperatures, approximately 95C and pulverized to form a powdered product with a low bulk density whose water content can vary from 7 to 30%.
• the bulk density of the final product is dependent upon the amount of water employed for combining the carrier agent and the dichlorocyanurate.
• Moisture contents between and by weight form dense homogeneous products upon drying. As the moisture contents are increased up to 50% by weight, compositions of progressively decreasing bulk densities are produced upon drying.
• the range of the bulk densities for the compositions produced in this manner are from 0.439 to 0.802 grams/cubic centimeter.
• a storage-stable, free-flowing, thermal-decomposition resistant, low bulk density sodium dichloroisocyanurate dihydrate can be prepared from waterwet crystals of sodium dichloroisocyanurate dihydrate by contacting the water-wet dihydrate crystals with a water miscible organic solvent, then drying the solvent containing material at temperatures below about 48C to remove the contacting liquid and not the waters of hydration.
• a sodium dichloroisocyanurate dihydrate product is produced having a bulk density at least four times lighter than sodium dichloroisocyanurate dihydrate prepared in the conventional manner.
• low bulk density sodium dichloroisocyanurate dihydrate used to define the product of the invention means a sodium dichloroisocyanurate dihydrate having a bulk density of about 0.1 to about 0.3 grams/cubic centimeter.
• Sodium dichloroisocyanurate dihydrate may be produced by any conventional manner and used in the process of the invention.
• the dihydrate feed material may be in either dry or water-wet form.
• dry dihydrate it is advantageous to dissolve the dry crystals in water in order to dissolve the crystalline agglomerates.
• the solution containing the dissolved crystals is then evaporated and/or cooled, e.g. to below 12C, to reform the crystals.
• the reformed crystals are then separated from the aqueous solution, mixed with the contacting liquid, and dried.
• Precipitated sodium dichloroisocyanurate dihydrate produced by either conventional means or by dissolving crystalline agglomerates discussed above may be separated from the bulk of the aqueous reaction solution by any well-known means, such as by filtration, centrifugation, decantation or the like.
• the treatment with the contacting liquid is carried out by adding the organic solvent to the precipitate and contacting and mixing the precipitate with the organic solvent.
• the organic solvent should be added almost immediately to the separated precipitate to remove any residual reaction solution.
• Such contacting results in the formation of low bulk density crystals which are approximately 3 X microns in size. If the mother liquor is allowed to remain on the crystals during separation, the crystals will break and agglomerate, resulting in crystals of higher bulk densities that are about 6 X 30 microns in size. If the precipitate is allowed to dry, it will cake in such a manner that complete contact with the solvent will be impossible.
• the contacting liquid may be added completely at one time or added in small portions, each portion being drained completely before the next one is added. Generally, it is more efficient to employ two small portions of contacting liquid than one portion of the same total volume. When employing two or more portions of contacting liquid, the contacting liquid may be reused with fresh contacting liquid. Thorough mixing of the precipitate and contacting liquid is necessary if the full benefits of the invention are to be realized.
• the contacting liquid used for contacting the waterwet dihydrate crystals must be an organic solvent that is miscible with water.
• the boiling point of the solvent should be relatively low, that is less than about 48C, so that drying temperatures below about 48C will remove the solvent from the dihydrate but not the waters of hydration. If an organic solvent having a boiling point about 48C is desired, drying must be conducted under vacuum to assure drying at below 48C.
• the solvent should also be chemically inert in the presence of the dihydrate. Examples of organic solvents which may be employed in my invention are acetone, methanol, tetrahydrofuran, and acetonitrile.
• the dihydrate crystals After the dihydrate crystals have been thoroughly mixed with the contacting liquid, the dihydrate crystals are dried. Drying may be carried out by any known manner, such as by a warm air stream or in a vacuum oven.
• Drying temperatures below about 48C are employed, and preferably between 25 and 35C. Temperatures slightly above 48C may be employed if losses of minor amountsof water of hydration can be tolerated. Temperaturesabove about 66C are avoided in order to prevent the formation of the anhydrous salt. Drying temperatures are employed which will remove the organic solvent retained by the precipitate but which will not remove the sodium diehloroisocyanurate waters of hydration.
• the low bulk'density sodium diehloroisocyanurate crystals of the invention have an average size of 3 X 180 microns and a bulk density of about 0.1 to about 0.3 grams/cubic centimeter, preferably about 0.13 to about 0.25 grams/cubic centimeter. A particularly preferred bulk density is on the order of 0.13 grams/cubic centimeter.
• Upon heating, both waters of hydration are lost in one step at temperatures between 48 and 66C.
• These low bulk density crystals have the same excellent storage-stability and free-flowing properties as the conventionally prepared sodium diehloroisocyanurate dihydrate.
• the inventive crystals are also resistant to thermal decomposition, a property which is an especial advantage of the dihydrate material.
• EXAMPLE l-A Prior Art Preparation of Sodium Dichloroisocyanurate Dihydrate A by weight aqueous slurry of diehloroisocyanuric acid was prepared and fed into a reactor. A 50% sodium hydroxide solution was prepared and was simultaneously fed into the same reactor at a sufficient rate to maintain the pH at 6.8. The temperature of the reaction mixture was maintained between 20 and 25C by a water cooled heat exchanger. The resulting slurry containing precipitated sodium diehloroisocyanurate dihydrate was filtered through a medium porosity funnel to separate the salt from the aqueous medium. The separated salt was then gently dried at about 40C in a warm air stream for approximately 24 hours.
• the resultant product was a free-flowing, white crystalline sodium diehloroisocyanurate dihydrate material. Available chlorine was assayed at 55.2%, theoretical 55.4%. The dihydrates bulk density was 35 pounds/cubic foot (0.56 grams/cubic centimeter).
• EXAMPLE l-B Process of the Invention Sodium diehloroisocyanurate dihydrate was produced and recovered according to Example l except that no drying step was carried out. Immediately after filtration, the water-wet dihydrate crystals were thoroughly contacted and mixed with acetone. The acetone-wet salt product was then dried at about 30C in a warm air stream for approximately 24 hours. The resultant product was a fluffy, free-flowing, white crystalline product identified as sodium diehloroisocyanurate dihydrate material having an available chlorine assay of 55.2%; theoretical 55.4%. The dihydrate had a bulk density of 8.1 pounds/cubic foot (0.13 grams/cubic centimeter).
• a process for the production of a storage-stable, free-flowing, thermal-decomposition resistant, low bulk density sodium diehloroisocyanurate dihydrate which comprises contacting water-wet sodium dichloroisocyanurate dihydrate with a water miscible organic solvent, drying the solvent treated sodium diehloroisocyanurate at a temperature less than about 48C to remove the organic solvent and not the waters of hydration, and recovering a low bulk density, sodium dichloroisocyanurate dihydrate having a bulk density of about 0.1 to about 0.3 grams/cubic centimeter.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Detergent Compositions (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)

Priority Applications (15)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23494696

Family Applications (1)

Country Status (14)

Cited By (2)

Families Citing this family (1)

Citations (4)

• 1973
  • 1973-07-13 US US378829A patent/US3888855A/en not_active Expired - Lifetime
• 1974
  • 1974-05-28 CA CA200,997A patent/CA1012969A/en not_active Expired
  • 1974-06-05 IT IT23652/74A patent/IT1014811B/it active
  • 1974-07-04 NL NL7409041A patent/NL7409041A/xx not_active Application Discontinuation
  • 1974-07-05 FR FR7423414A patent/FR2241551B1/fr not_active Expired
  • 1974-07-08 BR BR5593/74A patent/BR7405593D0/pt unknown
  • 1974-07-10 BE BE146448A patent/BE817516A/xx unknown
  • 1974-07-10 DE DE2433113A patent/DE2433113C3/de not_active Expired
  • 1974-07-11 JP JP49078795A patent/JPS5037792A/ja active Pending
  • 1974-07-11 CH CH960574A patent/CH605852A5/xx not_active IP Right Cessation
  • 1974-07-12 ZA ZA00744479A patent/ZA744479B/xx unknown
  • 1974-07-12 GB GB3087474A patent/GB1442503A/en not_active Expired
  • 1974-07-12 SE SE7409193A patent/SE420092B/xx unknown
  • 1974-07-13 ES ES428242A patent/ES428242A1/es not_active Expired

Patent Citations (4)

Also Published As

Similar Documents

Legal Events