DE1467165A1 - Acid sodium aluminum ortophosphate complex compound - Google Patents

Description

Acid Sodium Aluminum Ortophosphate Complex

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The invention relates to a new acidic sodium aluminum orthophoephate complex compound of the formula

and a method for their production. It is proposed in particular for use as a leavening agent for dough.

Currently, three known compounds are referred to as acidic sodium aluminum orthophoephates. The compound of the formula NaAl ₃ H ₁₁₄ (PO ₁₁ ) 3.JiH ₃ O (described in U.S. Patent No. 2,550,490), commonly referred to by the name sodium aluminum phosphate or simply NAP, is currently available. the connection of this group that is of the greatest importance in trade. A more recent compound is the dehydrated form of NAP of the formula NaAl ₃ H ₁₁₁ (PO ^) ₃ (see, for example, US Pat. No. 2,957,750). The amorphous compound of the formula MaAl ₃ H ₁₁ (PO ₁ J) ₇ -S-SH ₂ O is described in U.S. Patent No. 2,995,421. These known acidic sodium aluminum orthophosphates are suitable, for example, as leavening agents for a number of baked goods, such as

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Melting cheese regulating additives and as fat-binding additives for meat.

The new compound is a finely divided, free-flowing, white substance that is present in individual particles. He is in a warm Wasaa completely soluble (however the dissolution process is irreversible, i.e. the substance can get out of the solution not be reprecipitated) and slowly settles with sodium bicarbonate in the presence of a low level of moisture around. The new aluminum acidic sodium orthophosphate is for it is particularly suitable for use in baking and is a particularly effective leavening agent for preserved doughs.

The new compound is preferably prepared by preparing a liquid reaction mixture with a stoichiometric ratio of Na: Al: P such as about 3: 2: 8 and then heating and stirring this reaction mixture to remove the excess water until it is dry forms crystalline product. Usually, sodium hydroxide or carbonate and a trivalent inorganic aluminum compound (e.g. AlpO, .3HpO) are added to the phosphoric acid (usually 75% or weaker) in the correct stoichiometric ratio while the acid is kept at a temperature between about room temperature and its boiling point. Preferably, the sodium reagent at 40 - added 120 ⁰ C - 60 ⁰ C and the trivalent aluminum compound at 90th Both additions can be made at the same time, the reaction temperature preferably being kept between about 80 and 100.degree. In any case, the rate of the reaction between the sodium or aluminum compounds and the phosphoric acid is increased by the elevated temperatures to a practically favorable value.

After adding sodium and aluminum to the aqueous phosphoric acid has formed the viscous, transparent, liquid reaction product, it must be dried

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to form the final crystalline product. The completely dried finished product shows a weight loss of about 15 Ί » when ignited, which corresponds to the constitution water. The Keaktionsge mixing is advantageously carried out at temperatures of about 45 IBO ⁰ C, preferably 80-120 ° C, dried. As the reaction vessel dries, it becomes progressively more viacos, becomes opaque and then finally begins to crystallize. The moist crystals are then dried to a constant weight, their chemical analysis then corresponds to the formula already given.

To produce the connection according to the invention can be both continuous and discontinuous Procedures were applied. A suitable discontinuous Ii : ües industrial process consists in dati one the Pour phosphoric acid into a large heated heating gel, dap is equipped with a wing agitator that Sodium and aluminum compounds are added and agitator activated (while ui <; temperature of the reaction vessel accordingly the process stage ^ r. changes) until a dry-white pro. ^ uKt forms. The reaction and drying times depend on the established method for the connection selected in the individual case (<i.e. whether it is continuous or carried out batchwise), of which initially contained in the acid and the sodium and aluminum compounds and that for the various Production stages from selected temperature. Usually the reaction time will not exceed 30 minutes. while drying require about 30 minutes to 3 hours can.

It has been found that the compound according to the invention is similar to that already known in the prior art Sodium aluminum phosphate (HaAl ^ II,. (PO-) g. 4HpO), in the form individually present crystalline particles can be produced, which under the microscope have a characteristic Let the shape be recognized. None of the other known crystalline

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Acid sodium aluminum orthophosphate can be recognized so easily by examination under the microscope, since these form irregular, agglomerated particles. Even the compound according to the invention has a strong tendency to agglomerate during manufacture. If it is prepared from a solution containing a stoichiometric ratio of Na: Al: P such as 3: 2: 8 by conventional industrial processes, it agglomerates to form a product that is practically indistinguishable from the known substances with the naked eye lets distinguish. In the case of the new compound, this tendency to agglomeration can be eliminated if the product is precipitated from a solution (reaction mixture) which contains excess phosphoric acid. The sodium: aluminum ratio of this solution is preferably about 3: 2 while the amount of phosphoric acid is greater than that required to provide 8 gram atoms of phosphorus per 3 gram atoms of sodium and 2 gram atoms of aluminum. In the precipitation process, the solution is concentrated until a precipitate forms; this is quickly washed with water to remove the precipitated substance, the remaining crystalline product is quickly dried.

Fig. 1 is a photomicrograph of the new compound of the invention, prepared by precipitation from a solution old excess phosphoric acid. The particles are enlarged 220 times.

Figure 2 is a photomicrograph of NAP particles (HaAl ₅ H ₁₄ (PO ₄ ) Q ^ H ₂ O) made by essentially the same process as the fabric shown in Figure 1 ', at exactly the same magnification.

A comparison of Figures 1 and 2 shows that the particles of the new compound are single, square, transparent crystals, while the

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known nap crystals are slightly larger and hexagonal Have shape. In addition to what can be seen by the photomicrograph, it was found that both the particles of the new compound as well as those of the NAP compound are in the shape of flat plates "A". At microscopic Examination with a polarization grating can be observed that the crystals of the new compound are considerably more birefringent than the NAP crystals.

Although - as already mentioned - the tendency of sodium aluminum orthophosphates to agglomerate after the If the state of the art can prevent visual identification, they can all be done by various standard analytical methods can be easily characterized. The compound of the present invention is also easy to determine. Every acidic sodium aluminum orthophosphate has a certain reactivity, acidity, elemental analysis, X-ray diagram (with the exception of the amorphous substances according to the state of the art), etc.

Its X-ray powder diagrams are particularly useful in identifying the compounds of the present invention. From these diffraction diagrams it is clear that the new connection has a unique and distinctive crystal lattice. The diffraction patterns of the two were also known crystalline 'acidic sodium aluminum orthophosphates differ from that of the new compound, which proves that they have a different crystal lattice. The d-distances for the lines of greatest intensity are in the known sodium aluminum phosphate (NAP) at 2.99, 3.67 and 8.70 A, while

it is about 3.08, 3.94 for the compound according to the invention ο

and 8.35 A. A similar discrepancy is seen when comparing the main lines of dehydrated NAP, NaAl-Z-Ej, (PO,) q, with which the new compound can be seen. Table I shows the d-spacings and the relative line intensities of the X-ray powder diagrams from NAP, dehydrated NAP and the compound of the invention.

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_: H ₁₅ (P0 ₄ ) ₈ Table I. Dehydrated NAP " intensity intensity NAP d 40
100 d 100 d intensity O
A.
8.64
7.73 0
8.35 ο
A.
8.70 100

5.98
5.55 70
50 4.77 5 4.32 20th 4.13 10 3.94 100 3.67 10 3.56 5 3.45
3.31
3.21 50
10
10 3.08
2.99 100
5 2.78 50 2.73 5

7.50

10

4.74 4.25

3.67

3.21

3.08 2.99

2.82

2.77 2.73

2.43

2.38 2.22 2.14 2.02 1.91 1.83

5 5

100

40

15 75

30th

20 20

25th

5 5

15th

30th

30th

4.83

4.11

3.92 3.74

3.61 3.51

3.14

2.99 2.88

2.75 2.55 2.42

1.91 1.82

15th

15 50

30 30

10

25 5

20th

20th

3 3

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The relative intensities of Table I were determined from X-ray film diffraction patterns, using values from 0 for no lines to 100 for lines of highest intensity. The values have been corrected slightly, in order to compensate for the differences in image intensity that occurred in the films, which can be traced back to the usual minor discrepancies during exposure and development.

The following specific examples illustrate the preparation and properties of the compound according to the invention.

Example 1:

522.5 g of 75% orthophosphoric acid were placed in a "Hobart" mixed jar fitted with a "Glass CoI" heating jacket. A dry mixture of 80 g of soda ash and 78 g of hydrated clay was then slowly added to the orthophosphoric acid. When the addition was complete, the mixing vessel was heated so that the mixture was kept at a temperature of 65-75 ° C .; the paddle stirrer was switched on. The stirring and heating was about 2.5 3td. continued. It could be observed that the mixture reacted within this time and slowly changed from a viscous liquid to a dry crystalline state. After it had cooled, the mixture was ground until it passed a sieve with a mesh size of about 0.105 and dried in an oven at 55 ° for about 4 hours to a constant weight. The dried product showed irreversible but essentially complete solubility in H ₂ O. The X-ray Fulver diagram of the product is given in the first two columns of Table I above.

Essentially the same procedure was followed as in the example above, but with the addition of sodium

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(in the form of calcined soda) changed, so that reaction products were formed, the 2.00, 2.50, 3.50 and 4.00 gram atoms of sodium The X-ray powder diagrams showed each containing 2 grams of atoms of aluminum and 8 grams of atoms of phosphorus of the products which contained either more or less sodium than the theoretical amount, some lines of the new compounds, however, the intensity was noticeably reduced and / or new lines appeared. Deviations in the diffraction patterns could already be seen when the amount of sodium only deviated from the theoretical value by 0.25 gram atom. Apparently the deviation from the stoichiometric quantities led to the formation of mixtures, the NAP, the new compound, and probably contained an amorphous substance. As one would expect, the main lines of the NAP appeared when the amount of sodium is not the stoichiometrically required amount reached. In Table II are the d-spacings and intensities of the main lines of the X-ray powder diffraction patterns of the mixtures and the product, the Na: Al: P in the ratio of 3: 2: 8, with the lines appearing at 8.70, 3.61 and 2.99 being the three main lines for the NAP are.

relationship the Table II: (Na: Al: P) 2: 2: 8 2 »? ·· 2 Participants in the evaluation : 2: 8 d 50 30th : 8 3: 2: 8 3.5 8.70 50 70 40 8.35 50 70 100 40 3.9 * » 50 30th 100 3.67 50 70 40 3.08 35 20th 100 239

4: _2_: 8

0x0

The main lines of nap always occur when the sodium amount does not reach the theoretically calculated value. The diffraction patterns show that the 2: 2: 8 mixture in equal parts from NAP and the new connection

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consists. If the sodium content is even lower, the mixture will contain about 3: 2: 8 material. It has also been found that an increasing aluminum content of the reaction mixture easily leads to the formation of mixtures which _{contain the new compound and a compound of the formula Na 5} Al ₅ H ₁₂ (PO ₄ ) Q.5HgO

(described in the concurrent registration

our no. 9585; U.S. Application No. 172,865, filed February 13, 1962). On the other hand, increasing sodium content easily leads to the formation of mixtures of the new compound and a compound of the formula Na ₄ AIpH ₁₄ (PO ^) ₈ .IHpO (described in the concurrent

Registration our no. 9584; US filing

No. 172,852, filed February 13, 1962).

Example 2:

A mixture of 900 g of 75% H ₅ PO ₄ , 80 g and 58.5 g of alumina was placed in a 1000 ecm three-necked flask equipped with a stirrer, a thermometer and a reflux condenser. The mixture was then heated to reflux temperature until the solution became clear (a constant boiling temperature of 119 ° C. was reached under reflux). Then the reflux cooler away and evaporate the water until the temperature of the solution reached 140 ⁰ C. The mixture was then allowed to cool with stirring until the formation of a thick, opaque slurry was observed. This slurry was diluted threefold with HpO and then filtered through filter paper. The crystalline residue was scraped off the filter paper, washed with water and acetone and air dried. The analysis of the dried crystals showed 5.8 # Al, 26.9 # P and 7.9 in comparison to the theoretically calculated values of 5.95 # Al, 27.3 # P and 7.6 % Na. After heating, a weight loss of 15 # was found, which is theoretical. The refractive indices in oil were 1.502, 1.518 and 1.526. Fig. 1 shows a photomicrograph of this product.

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The compound according to the invention is suitable as an all-purpose leavening agent for cakes, biscuits and the like
the other acidic sodium aluminum orthophosphates do not impart any off-taste to the baked goods. Its "neutralization value", the usual quantitative indicator in the baked goods industry, is between about 98 and 105. The neutralization value is a measure of the weight of sodium -

bicarbonate, which are neutralized by exactly 100 parts by weight of a certain driving acid. Almost all of them so far
known driving acids have neutralization values of about 60-115.

In addition to its general use as a driving acid, the compound of the invention is particularly suitable for use in frozen preserved doughs. It is
It is known that canned dough, like canned pre-baked goods, has a much longer shelf life than the usual
Bakery products. This is due to the fact that the air
has no access to the closed container, which inhibits the development of bacteria. However, unlike the pre-baked canned goods, the doughs are usually preserved in such a way that a substantial amount of air is entrapped in the container. The containers are permeable to gas (the side walls are usually made of layered cardboard) so that the air can be removed after the ends are tightly sealed. This air will
removed by "subsequent" sealing "of the packaged dough, ie by heating the packaged dough in a" Diehtungsraum "at about 32 C until a reaction between the driving acid and the bicarbonate of soda components takes place, whereby in the sealed Container COp gas evolves, the enclosed air and
part of the COp gas escapes from the container at the beginning; However, if the dough has risen sufficiently, it closes the openings in the permeable wall so that the pressure in the container increases. If the right pressure during the
"Abdiohtung" is not achieved, air easily flows back into the container when the dough is then frozen »

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(at 1.5 - 3.5 ° C). The sealing conditions must be carefully regulated and the driving acid must be one Have responsiveness that creates the desired overpressure »approx. 0.35 - 1.05 atmospheric pressure during the sealing process. Otherwise the air cannot be expelled from the container or, if the acid reacts too quickly, the container may burst. To regulate the sealing process, a sealing time of 1 hour was generally assumed as a unit in the baking monitor industry.

Except for one or maybe two of the driving acids currently available, all of them either react too quickly or too slow and thus did not meet the strict requirements for sealing preserved doughs. In Table III below lists the seal pressures produced by the new joint and NAF will. The neutralization values agreed. For comparison, typical values for the sodium pyrophosphate leavening acid are also given (probably the only and undoubtedly the most important driving acid commonly used for airtight dough).

Tabel

Sealing prints at Dough 1 Sealing
pressure: 0.28 atm 32 ° C for Biseuit part «. Dough 3 atü NaAl ₅ H ₁₄ (P0 ₄ ) ₈ .
4H ₂ O 15 minutes. 0.49 atm dough 2 Sodium acid
Pyrophosphate atü Leavening acid 30 min. 0.77 atm Na ₅ Al ₂ ] H ₁₅ (PO ₄ J ₈ . , 35 atü 45 min. - 0 , 77 atü 60 min. _ 0 atü 0 , 05 atü 75 min. 0 atü O ₁ 0 , 28 atü O ₁ 0 , 56 atü I ₁ 1 , 05 atü

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Neither the amorphous compound of the formula NaAlJfI, -, (PO.) Γ.5-8HpO nor the dehydrated NAP are suitable Leavening agent components for airtight packaged dough. The inventive Compound is therefore the only neutral-tasting acidic aluminum orthophosphate that is suitable for frozen, Airtight packaged doughs are suitable. Baked goods made from dough containing the neutral-tasting leavening acid, have an improved taste.

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Claims (2)

Patent claims: Acid sodium aluminum ophosphate complex the formula) 2. A process for the preparation of a sodium _{aluminum phosphate of the formula Na 5} Al ₂ H ₁₅ (PO ^) O, characterized in that sodium hydroxide or sodium carbonate and a trivalent inorganic aluminum compound are reacted with aqueous phosphoric acid at a temperature between about room temperature and the boiling point of the acid and The sodium and aluminum compounds are used in stoichiometric ratios of about 3 sodium atoms for every two aluminum atoms and the phosphoric acid compound is used in at least an amount such that it is sufficient to react with all of the sodium and aluminum compounds, and the resulting viscous solution to between about 45 and 16O ⁰ C heated is carried out until complete reaction between sodium, aluminum and phosphoric acid. For STAUFFER CHEMICAL COMPANY Lawyer 909885/1282 Blank page